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n1das

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  1. I have played around with the companding option in my commercial radios I use on GMRS. I end up turning the compander off after a while because of the issues it causes. The companding feature does work as advertised to help clean up the audio SNR. The companded audio has a "processed" quality to it and I don't mind that. The problem is it requires ALL radios talking to each other to also be using companding in order to sound right. It's an all or nothing type deal. Radios that don't compress their transmitted audio will sound muffled and distorted when heard out of companded radios. The expander in the receiver expands audio that wasn't compressed originally and blows it apart and sounds like 'expletive'. The compander is best left disabled when you have a mix of radios that do and don't compand their audio. Motorola includes a low level expander (LLE) option in their top tier radios. When using LLE, the transmit audio is not compressed, only the received audio is expanded by a small amount. It gives the audio a very slightly "fuzzy" quality to it under some conditions. Overall if a radio has companding capability, the radio needs to include the option to disable the compander. The compander feature should be OFF by default. The Motorola Talkabout FRS bubble packs use companding. Motorola calls this feature "X-Pand". The compander is always enabled and with no option to disable it. With Motorola's VHF and UHF business radios, the Business Bubble Packs as I like to call them also compand audio on narrow bandwidth channels with no option to disable the compander. People who have complained about bad receive audio quality out of the Motorola Talkabout FRS bubble packs are really complaining about the effects of the compander on the received audio, especially when hearing radios that don't compress their transmit audio because they don't have companding. Motorola could greatly improve the Talkabout FRS bubble packs by simply adding the option to disable the compander. My wife (g/f at the time) and I had a pair of Motorola Talkabout 250 FRS bubble packs in the early days of FRS. The Talkabout 250 was one of the early 14-channel FRS bubble packs from Motorola. It was one of the first models to push their "X-Pand" audio companding feature. Motorola added X-Pand to all of their analog radios back then. Motorola's top tier radios have the ability to enable or disable companding on a per channel basis. With Motorola's FRS bubble packs and their business bubble packs, the compander is always enabled. The Talkabout 250 had LOUD audio for hearing them in noisy environments which I liked but the companded audio sounded like 'expletive'. The radios aggressively companded the audio by over-compressing the transmitted audio and over-expanding the received audio. The companded audio quality was so bad and to the point that basic functionality of the radio was impaired. The radio was almost unusable with radios that don't compand their audio. It was THAT bad. Reducing the expansion ratio in the expander part of the companding system would have helped a lot. Wikipedia article on companding: https://en.wikipedia.org/wiki/Companding
  2. It IS interesting and I don't know if it repeats on the same frequency hopset or not. I don't know the details of how it works. It would be interesting and cool to try but I don't feel like spending the $,$$$$.$$ for a DRX. I think the cable that comes with the DRX for connecting the two units together is 10 ft or 20 ft long. There is an optional 50 ft cable for it to get the two units further apart. The current DRX based on a pair of DLRs is a refresh of their older DRX unit which was based on a pair of legacy DTRs and with the same price tag. The legacy DTR410/550/650 models were discontinued in November 2018 when the DTR600/700 models were released. Cane Wireless needed to develop a DLR based DRX going forward. The DRX also needs to work with the Profile ID mode channels which the legacy DTRs can't do because they don't have the 4 digit PIN feature. From what I read about the DRX is that the digital audio delay between radios approximately doubles when talking through the DRX. Multiple DRXs on the same channel can be used to further extend coverage on a channel but Cane Wireless recommends against it because the audio delay increases and audio quality may decrease. This makes me wonder if analog audio passes between the two units making up a DRX repeater. The audio quality would decrease due to effects of double vocoding, etc.
  3. Cane Wireless sells a range extender / repeater for Motorola DTR and DLR radios. Cane Wireless DRX Range Extender for Motorola DTR/DLR radios: http://www.canewirelesspro.com/drx-repeater.html The DRX is not a repeater in the conventional sense like a GMRS repeater. The DRX range extender / repeater consists of a pair of DLR radios running custom firmware and connected together to behave as a repeater or range extender. Simply connecting a pair of stock DLRs or DTRs together will not work. The two DRX units that make up the repeater are placed physically apart from each other and connected together with a cable. The DRX (1 pair of units) repeats a single Public group, Private Group, or Profile ID group. IOW, it repeats 1 channel in a DTR or DLR radio. When dealing with multiple channels, one DRX (1 pair of units) is required for each channel to be repeated. Strategic placement of a pair of units making up a DRX is critical. The application for the DRX is to extend coverage inside large buildings or to fill in dead spots in coverage areas. It isn't something you would normally place at a mountaintop site, although it would be interesting to try. Placement of units requires there to be some overlap between the original coverage area and the desired extended coverage area. A typical application is to provide coverage through a firewall in a building blocking coverage and you would place a unit on each side of the wall. In tall buildings, the DRX could be used to extend floors of coverage inside the building. Cane Wireless also sells a weatherproof kit for the DRX: http://www.canewirelesspro.com/wdrx-weatherproof-kit.html
  4. I am curious if your newly bought DLRs are new enough to be expandable to 10 channels with the CPS. The DLR1060 has 6 channels by default but this can be expanded to 10 channels with the CPS as an unadvertised feature. I stumbled upon this like a few other people have when I was tinkering with my DLR programming. Then I checked the model information at the top of the main screen in the CPS and it said 10 channels supported. Duh. Should have checked that first. The 2 channel DLR1020 is not upgradeable. The 1020 and 1060 are identical radios except for the number of channels supported. The 1020 is the entry level DLR model. For anybody in the market for DLR radios, the DLR1060 is the DLR model to get. Early DLR1060s were not expandable to 10 channels and were stuck at 6 channels. Motorola later updated the firmware to add 10 channel capability but still markets the DLR1060 as a 6 channel radio. I'm not sure when the firmware change was made but I recall it was around 2017. The last 2 digits in the firmware version is .01 in the newer DLRs. The firmware in early DLR1060s that were limited to 6 channels ends in .00. 10 channel capability in the DLR1060 is supported in CPS versions R05.01 and newer. The latest CPS version is R08.02.
  5. The deep dive is hard to avoid because there is so much information to unpack. The DLR quick ref guide is a good read. I also recommend downloading the CPS and exploring the the programming there to learn your way around the radio. Pull up a default DLR radio template in the CPS and go from there. The CPS has help available for each feature.
  6. They won't beat range with a 40W mobile and external mobile antenna but they will work surprisingly well. While I never got my DTR/DLR radios to set any range records, my range record stands at 12 miles, from Cocoa Beach Pier in Cocoa Beach FL to the steps leading down to Hightower Beach in Satellite Beach FL. A friend helped me test this. We also had our 4W Part 90 UHF portables on GMRS to compare to. (We are both GMRS licensed.) The 12 mile trip is along the FL coast and there is a bit of coastline in the way so it's not entirely line of sight. It worked on the DTRs and on GMRS. With GMRS, the received signal was noisy and we each had to find a hot spot and stay there in order to communicate. On the DTRs it was clear audio all the time, right up to the limit of coverage. The DTRs occasionally required moving around to find a better spot but this was less critical than on GMRS. We have done this test with DLR radios and results were the same. We also found that when the DTR/DLRs went away when finally out of coverage, GMRS portable coverage was already gone too. Overall the DTRs and DLRs worked a little better.
  7. The 4 digit Profile ID Number (PIN) feature is a new feature which started with the DLRs when they came out in 2015 and was continued with the new DTR600/700 models. The legacy DTRs don't have the PIN feature. The PIN modifies the talkgroup ID for the first 20 public groups so they no longer are public groups when the PIN is a nonzero value. The PIN feature also added Call All Available and Page All Available which are new features related to the PIN feature. The legacy DTRs don't have the PIN features. The 4 digit PIN provided a new way to easily secure your channels without needing the CPS. The default PIN is 0000 (off). The default channels in the DLRs are compatible with the default public groups in the legacy DTRs when the PIN is at the 0000 default. If you are using the PIN feature, you will have to set it back to 0000 to work with the legacy DTRs if all other settings are at their defaults. If you use the CPS, you can set up a mix of channels which use the PIN feature on some channels to secure them and have public groups on other channels identical to the legacy DTRs. Setting up a mix of channel types requires the CPS. The legacy DTR410/550/650 has public groups and private groups. The legacy DTRs call them talkgroups instead of channels. Channels in the legacy DTRs refers to the 10 frequency hopsets available to use. Hopset #1 (channel 1 in legacy DTR-speak) is the default. The DLRs and DTR600/700 refers to channels instead of talkgroups because that's what people are more familiar with (i.e., WTH is a talkgroup?). The end user sees them as channelized radios anyway. I tend to interchange the use of talkgroups and channels. Available channel types in the DLRs and DTR600/700 are Profile ID mode (PIN required), public group (no PIN), private group (no PIN), and 1 to 1 private call (no PIN). The default channel type is Profile ID mode. Available talkgroup types in the legacy DTRs are public group (no PIN), private group (no PIN), and 1 to 1 private call (no PIN). The default in the legacy DTRs is public group. DLRs are capable of private 1 to 1 calling like the DTRs but requires the CPS to set up and a channel has to be dedicated to it. Private 1 to 1 calling wastes a channel in the DLRs and is a PITA to set up. The DLRs have a 1 button Private Reply feature to enter a private 1 to 1 call after hearing a call from another radio. Private Reply is the default for the top button on the DLRs. The legacy DTRs and the DTR600/700 have a display and can dial up an individual radio to initiate a private 1 to 1 call and also have the 1 button Private Reply feature. The MOTOTALK platform that the DTRs and DLRs use is an ID based system where each radio has its own 11 digit private ID in hardware, similar to an electronic serial number (ESN). A radio in a public group will respond to any incoming private ID on that public group ID. With a private group, a radio only responds to incoming Private IDs that are members of the private group. This means that the private ID of every radio in a private group has to be programmed into every radio in the private group. With a private group, a radio only hears and talks to members of the private group. All other DTRs and DLRs in range and using the same frequency hopset are locked out of the group. The PITA with private groups is when adding or replacing radios in a private group, ALL radios in the group have to get reprogrammed to add the new private IDs. The DTRs have Over the Air (OTA) cloning ability to update a fleet of radios with new private IDs. The OTA cloning capability is useful for updating large fleets consisting of hundreds of radios. Private groups make the DTRs and DLRs very secure but they are a PITA from a programming and maintenance standpoint. Programming private groups into the DTRs and DLRs requires the CPS. With the legacy DTRs, programming private groups was the only way to secure them except for 1 to 1 private calling. The PIN feature addressed this issue in the DLRs and DTR600/700. The PIN feature in the DLRs and DTR600/700 made it easy to take DLRs and DTR600/700s at their factory default settings and set the PIN to secure them. The default channel type on all channels is Profile ID mode. When adding or replacing radios in a fleet, just set the PIN in the new radios to match what the fleet uses and you are done. Choose a favorite 4 digit PIN that's easy to remember and hard for others to guess. Don't using anything obvious like 1111 or 1234, etc. This is the easiest way to secure them if all radios are at the factory default settings except for setting the 4 digit PIN. The DLRs have OTA cloning capability to clone the PIN to a fleet of DLRs to secure them instead of having to manually set the PIN in each radio. The DLRs speak the channel name given that the radio doesn't have a channel knob or a display. You can customize the channel names with the CPS to make your own channel names if you want. "Channel One", "Channel Two" etc. are the default channel names. You can set up custom names like "Security", "Maintenance", "Loading Dock", etc. The name of individual radios can also be customized. You can create custom names like "Dave's DLR radio", "Lisa's DLR radio" etc. The custom radio name plays when the radio first powers up. The DLR quick reference guide is a worthwhile read. https://www.motorolasolutions.com/content/dam/msi/docs/products/two-way-radios/on-site-business-radios/dlr-application-briefs/DLR-Quick-Reference-Guide.pdf
  8. Thanks. I just made a few minor edits. Maybe the next thing for me to do is write up a DTR/DLR programming overview and explain a lot of the workings. Programming the DTRs and DLRs is often cryptic and befuddling to new users. No programming is needed to use DTRs and DLRs right out of the box at the factory default settings. Customization of features and settings requires the CPS. Some settings can be changed without requiring the CPS. Programming the legacy DTR410/550/650 is cryptic and the DLR programming cleaned up a lot of things and made it a little less cryptic. The DTR600/700 models program like the DLRs. I suspect the DTR600/700 models use the DLR's code base. I am not surprised Motorola adopted the DLR way of programming going forward. The DTR600/700 models are backward compatible with the legacy DTRs but it requires some understanding of the differences. When I owned DTR650s, DLR1060s, and DTR700s, I had them all working with each other on public and private talkgroups. The DLRs and DTR700s added a 4 digit Profile ID Number (PIN) feature which the legacy DTRs don't have. I had my DLRs and DTR700s working with each other on Profile ID mode channels. The PIN feature allows you to take DLRs right out the box and set a 4 digit PIN to secure all channels in them without requiring the CPS. With the legacy DTRs, the only way to secure them was to use the CPS to program private talkgroups into them. Motorola made it insanely easy for DLR users and DTR600/700 users to secure their channels in radios right out of the box without needing the CPS. A lot can be learned about them by downloading and installing the CPS and exploring the DTR and DLR programming. The CPS has default DTR and DLR templates to work from so you don't need to read a radio first to use the CPS and play around with the programming. The latest CPS version is R08.02 and programs all of the older models too. You don't need an older version of the CPS to program an older radio. Just use the latest version of the CPS.
  9. Below is general information on the Motorola DTR and DLR series 900MHz FHSS digital radios. I am a user of the DTRs and the DLRs and have become a serious fan of them because they are professional quality and work amazingly well. I own a small fleet of legacy DTR650 radios and a small fleet of DTR700 radios. I have also previously owned a small fleet of DLR1060 radios. DTR600/700: https://www.motorolasolutions.com/en_us/products/two-way-radios/commercial-business-two-way-radio-systems/on-site-business-radios/dtr-series.html DLR1020/DLR1060: https://www.motorolasolutions.com/en_us/products/two-way-radios/commercial-business-two-way-radio-systems/on-site-business-radios/dlr-series-digital-radio.html CPS download: https://www.motorolasolutions.com/en_us/products/two-way-radios/commercial-business-two-way-radio-systems/on-site-business-radios/dtr-series/dtr700.html#tabresource The Motorola Business Radio CPS is a free download from Motorola and programs all of their Business Radio models. CPS cable on Amazon: https://www.amazon.com/Motorola-HKKN4027A-Programming-Cable-Black/dp/B00EC2PV6A/ref=sr_1_1?dchild=1&keywords=motorola+HKKN4027A&qid=1613093281&sr=8-1 The same CPS cable is used for programming all of Motorola's business radios. The one exception is the legacy DTR410/550/650 models because they use a different CPS cable. No programming is needed to use these radios out of the box at the factory default settings. The DTRs and DLRs work with each other right out of the box at the factory default settings. Customization of settings and features requires the CPS. Some settings can be changed without the CPS. The fastest way to get some DTR and DLR radios talking to each other if they don't already do so is to reset all of them to the factory default settings and then go from there. You don't need the CPS or the cable to get started with the DTRs and DLRs. Motorola has made it insanely easy to get started with them. Motorola DTR550 case study: https://www.motorolasolutions.com/content/dam/msi/docs/business/_documents/case_studies/rutland_healthcare_case_study.pdf The Rutland Healthcare case study is a bit dated as the DTR550 was used. The legacy DTR410/550/650 models have been on the market since 2006 and were discontinued in November 2018, marking the end of a 12 year production run. Support for the DTR410/550/650 models end on November 30, 2023. The DTR600 and DTR700 are the replacement models for the legacy DTR410/550/650 models. DTR history: https://en.wikipedia.org/wiki/MOTO_Talk The DTRs and DLRs are a spinoff from Motorola's MOTOTALK feature in several NEXTEL iDEN phones years ago. NEXTEL called this feature Direct Talk and is not to be confused with the DirectConnect PTT feature which worked through NEXTEL's iDEN network. The DirectTalk feature works PTT simplex phone to phone on 900MHz and uses FHSS. The killer app for this feature is for PTT use between phones when network service is spotty or unavailable and phones are close enough to each other to communicate. NEXTEL phones were popular with contractors and other professionals at jobsites and there was nothing more frustrating than the DirectConnect PTT feature would not work because one or more phones had no network service and phones were still relatively close to each other. The off-network DirectTalk feature provided a solution. The DTRs and DLRs use the same FHSS system but were coded differently from the phones to be incompatible and supposedly was done on purpose. The DTRs and the DLRs are the modern day implementation of the MOTOTALK platform. The legacy DTR410/550/650 models shared a common design with a NEXTEL phone during development and were originally part of the same design project until they spit apart to become separate products. Users of the legacy DTR410/550/650 models will notice that they are very NEXTEL-like in their behavior. The DTRs are commercial radios and loaded with features for business radio users. However, they often are too much "radio" for the average retail business user. Retail users just want a small radio with no keypad and display and minimal features to keep it simple. The DLRs are Motorola's answer to that. DLR = Digital Lightweight Radio, according to Motorola. The DLRs have the features of the DTRs, minus a display and keypad and channel capacity but are compatible with the DTRs. The DLRs were released in the summer of 2015. The DLRs are incredibly easy to use. The DLRs appear to be marketed toward users of the UHF analog CLS series analog business radios that are very popular for retail use. The DLRs seem to make sense for the target market. Some people don't like the large round PTT button on the front of the radio because they are so accustomed to PTT being on the left side of the radio. The DLRs are smaller than most FRS bubble packs and the front button makes sense for the very small size and thin form factor. A DLR radio is comfortable to hold in either hand and a thumb press activates PTT. I found the round front PTT button makes perfect sense for such a small radio. Old retired NEXTEL phones with the off-network DirectTalk feature can be found very cheaply on eBay. The i355 is a good model to look for. There are several videos on YT demoing their use. Factory fresh new batteries are still available for them. I know that because the legacy DTRs use the same battery and I recently re-batteried my DTR650 fleet. The one gotcha with old NEXTEL phones is they need to have a SIM card in them that was previously activated on an iDEN network to activate the DirectTalk feature. The MOTOTALK platform is an ID-based system and each phone or DTR/DLR radio has its own unique 11-digit Private ID, sort of like an Electronic Serial Number (ESN). In the DTRs and DLRs, this is ID loaded by Motorola at the factory and is not changeable by the end user or with the CPS. For private talkgroups and private 1 to 1 calling, individual radios only know each other by their 11 digit Private ID. NEXTEL phones with the DirectTalk feature form the 11-digit Private ID from 1 plus the area code and phone number that was assigned to the phone when it was activated on the network. This is why an old NEXTEL phone must have a previously activated SIM card in it to enable the DirectTalk feature. DTR/DLR FHSS on 900MHz: The DTRs and DLRs use a hopset of 50 frequencies spread across the entire 902-928MHz band and spend no more than 90ms on any given freq in the hopset. The DTRs make about 11 hops per second. The digital modulation on a given freq in the hopset is according to an 8-level modulation scheme. The occupied BW on a given freq in the hopset is around 26 kHz. Motorola's VSELP vocoder is used. VSELP is what NEXTEL phones used. Per FCC 15.247, an FHSS device operating in the 902-928MHz band must use a minimum of 50 frequencies in the hopset and output power is limited to 1W (+30dBm). The legacy DTRs were FCC certified at 890mW (+29.5dBm). The DTR600/700 models were FCC certified at 830 mW (+29.2 dBm). The DLRs were FCC certified at 880mW (+29.4 dBm). The few tenths of a dB under the +30dBm legal limit is to account for measurement uncertainty and slight variation in power output from unit to unit and not exceed the 1W (+30dBm) legal limit. The power numbers in the FCC certs reflect what was measured from the individual sample submitted to the accredited test lab for cert testing. My DTRs: I own a small fleet of legacy DTR650 radios and a small fleet of DTR700 radios. The DTR650 has been around since 2006 and was discontinued in November 2018 when the DTR600/700 models were released. The DTR600 and DTR700 models are the replacement for the legacy DTR 410/550/650 models. The DTR600/700 programs a little differently from the legacy DTRs but are fully backward compatible. I have also owned a small fleet of DLR1060 radios which also work with the DTRs. I later sold my DLRs to a friend for his business as I traded up to the DTR700 and kept my DTR650 fleet. At first he wasn't sure what he was going to use them for except maybe as rental radios for his customers but now he and his employees use them all the time around the office and at jobsites. The DTRs are my professional quality digital replacement for GMRS/FRS for local on-site simplex type use with family and friends. I never got them to set any range records but they work amazingly well and are capable of outperforming conventional Part 90/95 UHF portables on simplex. They totally blow FRS away. Where they beat other radios is when working inside buildings. Where they blow all others away is when aboard cruise ships. People who have used them on cruise ships report having full ship coverage on all decks compared to a pair of 4W UHF commercial portables on GMRS simplex which had trouble penetrating more than about 2 decks. Like when inside buildings, the ship is much more open at 900MHz compared to 462/467MHz (GMRS/FRS) and VHF MURS. The ship represents a compartmentalized metal enclosure with many reflections created. The many reflections inside the ship actually helps at 900MHz and the FHSS operation causes the individual hot spots and dead spots to hop around as the frequency hops. The FHSS operation effectively stirs the modes so to speak as the frequency hops. A coworker once asked me why not just use FRS? My answer was that I have already been doing that since FRS was created in 1996 and longer than that as a GMRS licensee (KAE9013) since 1992 and using good quality commercial gear. I want an all digital solution that is higher quality and more professional than FRS. The fact that they are completely scanner proof and can be made very secure via private talkgroups and private 1 to 1 calling comes as a bonus. While technically not encrypted, they can be made very secure. They are not monitorable on any consumer grade receiver (i.e., scanner) so don't even bother trying. I have also been bit by the digital radio bug as a ham (N1DAS) and want to use digital radios. I still have GMRS/FRS and MURS as a backup and for interoperability with non-DTR/DLR users but they are no longer my default go-to modes local on-site simplex use with family and friends. Aside from occasional light use of FRS with my young nephews when they come to visit, I hardly use GMRS/FRS at all anymore. I love these radios for local on-site simplex type use. My wife loves using them too when we are out shopping or doing whatever. She is not a ham but totally gets it when it comes to having radios to stay in touch. She has told me that she specifically DOES NOT want to use an FRS bubble pack radio. She much prefers using the DTR radios and wants to use only the good stuff (LOL) when we chitchat on the radio.
  10. No programming is needed to use the DTRs and DLRs with each other right out of the box at the factory default settings. Customization of features and settings requires the Motorola Business Radio CPS and is a free download from Motorola. Some features and settings on each model can be changed without requiring the CPS. The CPS cable is around $35 on Amazon. The same CPS and cable programs all of Motorola's business radios (RDV/RDU series, RM series, RMM series, etc.). The one exception is the legacy DTR410/550/650 models use a different CPS cable. You can download and install the CPS and play around with it and explore the DTR/DLR features and settings. The latest version of the CPS is R08.02 and programs all of the older models. You don't need a particular version of the CPS to program an older radio. Just use the latest CPS version. The Motorola Business Radio CPS can be downloaded from here: https://www.motorolasolutions.com/en_us/products/two-way-radios/commercial-business-two-way-radio-systems/on-site-business-radios/dtr-series/dtr700.html#tabresource There is no "pairing" of DTRs/DLRs like there is with Bluetooth devices. They pair up with each other on the fly with each PTT press. They do have to first be on the same frequency hopset and talkgroup ID in order to work with each other. A transmitting DTR/DLR listens for an acknowledgement from a receiving DTR/DLR radio during the NEXTEL-like PTT "chirp" talk permit tone to sync up to allow transmission to continue. When in range, transmission simply continues. When out of range, transmission stops after the PTT chirp and emits a warning beep indicating the call failed. The beep is a soft "do-do-doot" sound on the DLRs and DTR600/700. A DTR600/700 will also display a Call Failed message. The legacy DTR410/550/650 models will scream at you like an old NEXTEL phone and display a User not Available message. The end result is you will always know that you are in range and your transmission was heard and acknowledged by another radio. This makes it easy for range testing because you don't need two people for "Can you hear me now?" testing. You can leave one radio on the dining room table at home and then take the other radio with you and go for a drive and press PTT to see where you get connect hits. I have found people tend to use these radios right out of the box at the factory default settings, like FRS bubble packs. I have customized the programming in my DTRs but I purposely kept the factory default public talkgroups in my programming to listen to and talk to defaulted radios. I have private groups in my programming to keep my DTRs private when I want that. I have monitored activity on the default public groups in my travels when passing through major retail areas. The local Costco Wholesale near me uses DLR radios at the factory defaults and I can hear them when I'm in range. They are amazing radios.
  11. It IS a great idea! The Retevis 900MHz models caught my attention because I'm a DTR owner and have also owned DLRs too. The DTRs spend 90ms on each frequency in the hopset, or about 11 hops per second.
  12. Interesting. This link shows a different radio, with the 200 MOQ: https://www.retevis.com/Retevis-900MHz-License-Free-Two-Way-Radio/ This radio caught my attention given that I'm a DTR radio owner and use them a LOT. The DTRs are my professional quality digital replacement for GMRS/FRS and MURS for local on-site simplex type use with family and friends. My wife loves using them too when we are out shopping or doing whatever. The Motorola DTRs work amazingly well and are capable of outperforming conventional UHF Part 90/95 portables on simplex. They totally blow FRS away. Being all digital and completely scanner proof comes as a bonus. Rich, as a side note, is this 900MHz ISM forum a new forum just created on the site? If so, GREAT!
  13. The MOQ is 200 units. MOQ = Minimum Order Quantity. I don't think many people are willing to spend $12k for 200 of them. From studying the Retevis specs and given that I own a small fleet of Motorola DTR650 and a small fleet of DTR700 radios and are very familiar with them including their specs, I can only conclude that the Retevis 900MHz model is VAPORWARE. Many of Retevis' specs are for conventional analog and DMR radios and are N/A for a 900MHz FHSS digital radio. The specs appear to be a copy/paste from multiple sources, including from some of Motorola's marketing literature for the DTRs. I have yet to find an FCC ID for the Retevis model. Epic FAIL, IMHO. Motorola is very tight lipped about the DTRs and I highly doubt Motorola has opened the protocol up to the world. Maybe Retevis has one in the works as a reverse engineered version of Motorola's DTR radios or maybe Retevis has done their own thing to try to compete with the DTRs.
  14. Exactly what mbrun said. This is exactly how I approach it and I am licensed in both services. Ham Tech+ licensed (N1DAS) since 2/1984 and GMRS licensed (KAE9013) since 12/1992. My GMRS callsign resembles an old Class A CB callsign and predates the ULS. I was GMRS licensed before the creation of FRS in 1996 and the invasion of the bubble packs which followed.
  15. You can find the legacy DTRs very cheap on eBay but their condition is a big "?". The DLRs and DTR600/700 are still expensive on the used market. The DLRs are packed with the features of the DTRs, minus a display and some channel capacity and larger removable antenna. Don't be fooled by what appears to be very basic radio. It is packed with hidden features that work with the DTR's features. It is set up to be as basic as you can get like you said. Some people have commented that they don't like the large round PTT button on the front of the radio because they are so accustomed to a PTT button on the side of a radio. I found the large PTT button on the radio makes perfect sense because the radio is so small. A thumb press using either hand is all it takes and the radio is comfortable to hold. The PTT button of the front is different from what people are used to but it makes perfect sense for such a small radio. Battery life on a charge is in excess of 15 hours (5/5/90 duty cycle), similar to the DTR600/700 models. Another option is a pair of old NEXTEL Motorola i355 handsets. These iDEN handsets and a few other models have an off-network phone to phone feature which NEXTEL called Direct Talk. This is different from the NEXTEL DirectConnect PTT feature which used NEXTEL's iDEN network. The Direct Talk (DT) feature allows 2 or more phones to communicate simplex on 900MHz when in range of each other. It was useful for contractors at jobsites where one or more of their NEXTEL phones had no network service, which was common when working in a basement of a building. The DT feature offered a solution to this problem when phones had no service but were in simplex range of each other. The DTRs and DLRs are a spinoff from this feature. The DTRs and DLRs use the exact same FHSS system but differ in software only. The DTRs and DLRs are incompatible with the off-network DT feature and supposedly was done on purpose. The legacy DTRs and one particular iDEN handset (i325 or i325is, IIRC) were originally one and the same at the start of their design but at some point they split away and became separate products but still shared a common design. I suspect the software incompatibility came when more DTR-specific features were added to the DTRs. The Direct Talk (DT) user interface is a primitive version of the DTRs. MOTOTALK was the original silly Motorola name for this system. https://en.wikipedia.org/wiki/MOTO_Talk You can find i355 and other Direct Talk capable iDEN phones dirt cheap on eBay. I recently re-batteried my DTR650 fleet so I know replacement batteries are readily available for them. The one gotcha with these is they need to have a SIM card which has previously been activated on an iDEN network (NEXTEL) in order to enable the DT feature. The DTRs and DLRs have an 11 digit private ID in each radio that was assigned at the factory by Motorola and is not changeable by the end user or with the CPS. The ID functions as a hardware electronic serial number (ESN). The DTRs and DLRs use an ID-based system for private groups and 1 to 1 private calling. The radios only know each other by their 11 digit private ID. The DT features in the iDEN phones create this ID from 1 plus the area code and phone number in the SIM card that was assigned by the iDEN carrier (NEXTEL). If used phones have a SIM in them that was previously activated by an iDEN carrier then you are good to go. There are plenty of YouTube videos describing and demoing the Direct Talk feature. My wife (g/f at the time) and I had a pair of i355 phones back in the day and we played with the DT feature and that's when I first learned of the DTRs.
  16. Yeah the DTRs are not cheap. The DLRs are a little cheaper but not by much. Motorola has no plans to obsolete them anytime soon, part of why I'm not worried about them not working with non-Moto radios. The DTRs have developed a cult-like following over the years. Count me in! LOL. Use in hotels and schools are where they are popular. Some healthcare facilities are using them. Check out the Rutland VT case study. The Rutland Hospital case study is a bit dated as DTR550s were used. The DTR600/700 models are the replacement models. https://www.motorolasolutions.com/content/dam/msi/docs/business/_documents/case_studies/rutland_healthcare_case_study.pdf The DLRs were developed for retail business users as a digital upgrade or replacement for the very popular CLS series UHF business radios. The DTRs are loaded with features but often represent too much radio for the average business radio user in a retail environment. The DLRs are Motorola's answer to that. DLR = Digital Lightweight Radio, according to Motorola. The DLRs are smaller than most FRS bubble packs and makes them great "stealth" radios. The DLR's RF performance is identical to the DTRs. The DLRs make sense for the target market. The local Costco Wholesale near me is using DLR radios and I can hear them on the factory default public talkgroups when I'm in range. https://www.motorolasolutions.com/en_us/products/two-way-radios/commercial-business-two-way-radio-systems/on-site-business-radios/dlr-series-digital-radio.html The DTRs and DLRs all work with each other right out of the box at the factory default settings. No programming is needed to get them talking to each other. Customization of features and settings requires the Motorola Business Radio CPS, a free download from Motorola. The CPS cable is about $35 on Amazon. Many people appear to be using them right out of the box at the factory default settings like FRS bubble packs. I have programmed mine to set up private talkgroups to secure my fleet. I also kept the default public groups in the programming so they can still work with DTRs and DLRs at the factory default settings.
  17. I am a user of the DTRs and the DLRs and a serious fan of them. I own a small fleet of legacy DTR650 radios and a small fleet of DTR700 radios. The DTR650 has been around since 2006 and was discontinued in November 2018 when the DTR600/700 models were released. The DTR600 and DTR700 models are the replacement for the legacy DTR 410/550/650 models. The DTR600/700 programs a little differently from the legacy DTRs but are fully backward compatible. I have also owned a small fleet of DLR1060 radios which also work with the DTRs. I later sold my DLRs to a friend for his business. At first he wasn't sure what he was going to use them for except maybe as rental radios for his customers but now he and his employees use them all the time around the office and at jobsites. The DTRs are my professional quality digital replacement for GMRS/FRS for local on-site simplex type use with family and friends. I never got them to set any range records but they work amazingly well and are capable of outperforming conventional Part 90/95 UHF portables on simplex. Where they beat other radios is when working inside buildings. Where they blow all others away is when aboard cruise ships. People who have used them on cruise ships report having full ship coverage on all decks compared to a pair of 4W UHF portables on GMRS simplex which had trouble penetrating more than about 2 decks. The many reflections inside the cruise ship actually helps and the FHSS operation effectively stirs the modes as the frequency hops. The DTRs and DLRs use a hopset of 50 frequencies spread across the entire 902-928MHz band and spend no more than 90ms on any given freq in the hopset. The DTRs make about 11 hops per second. The digital modulation on a given freq in the hopset is according to an 8-level modulation scheme. The occupied BW on a given freq in the hopset is around 26 kHz. Motorola's VSELP vocoder is used. Per FCC 15.247, an FHSS device operating in the 902-928MHz band must use a minimum of 50 frequencies in the hopset and output power is limited to 1W (+30dBm). The legacy DTRs were FCC certified at 890mW (+29.5dBm). The DTR600/700 models were FCC certified at 830 mW (+29.2 dBm). The DLRs were FCC certified at 880mW (+29.4 dBm). The few tenths of a dB under the +30dBm legal limit is to account for measurement uncertainty and slight variation in power output from unit to unit and not exceed the 1W (+30dBm) legal limit. The power numbers in the FCC certs reflect what was measured from the individual sample submitted to the accredited test lab for cert testing. A coworker once asked me why not just use FRS? My answer was that I have already been doing that since FRS was created in 1996 and longer than that as a GMRS licensee (KAE9013) since 1992 and using good quality commercial gear. I want an all digital solution that is higher quality and more professional than FRS. The fact that they are completely scanner proof and can be made very secure via private talkgroups and private 1 to 1 calling comes as a bonus. I still have GMRS/FRS and MURS but they are no longer my default go-to mode local on-site simplex use with family and friends. Aside from occasional light use of FRS with my young nephews when they come to visit, I hardly use GMRS/FRS at all anymore. I have a small fleet of DTRs because they won't work with any non-Moto FHSS radios. I have them ready to hand out to friends and family members. I'm OK with them not working with non-Moto FHSS radios because I didn't get them to work with any other radios. No other manufacturer currently has a 900MHz FHSS radio that can hold a candle to the Motorola DTRs and DLRs. Retevis has dangled a 900MHz license-free model but it appears to be vaporware from what I can tell.
  18. Uhhh...NO. QT is Kenwood's Quiet Tone, aka CTCSS/PL. (analog tone) DQT is Kenwood's Digital Quiet Tone, aka DCS/DPL. (digital code) DN445 is what you need to encode on transmit. DCS 445 normal is often listed as D445N. T-DCS DN445 should work. The N (normal) and I (inverted) refer to the polarity of the DCS waveform. This is my favorite technical reference for DCS: http://onfreq.com/syntorx/dcs.html Other DCS information: http://www.repeater-builder.com/tech-info/ctcss/ctcss-overview.html https://mmi-comm.tripod.com/dcs.html For the current ETSI Standard TS 103 236 Continuous Tone Controlled Signalling System (CTCSS) and Digitally Coded Squelch Signalling (DCSS) document, check out the ETSI Standards search page and search for ETSI TS 103 236.
  19. What kb2ztx said. I have an N connector Bird 43 meter and love it. I have 2 UHF slugs for it and a couple of others. I like to have more than one slug handy for a particular band to serve as a sanity check if there's ever any question about the results and to check that a slug is not damaged (BTDT before). With a Bird 43 Thru-Line meter, there is no need for a "SWR meter." When tuning an antenna, your goal is to minimize the reflected power reading as much as possible. You simply measure the reflected power directly with the Bird 43 while tuning to minimize the reflected power. SWR is easily calculated from the forward and reflected power measured on the Bird 43 if you really want to know SWR.
  20. I keep wondering why the radio manufacturers keep using the SO-239 connector on mobile radios. Maybe because they've always done it that way. I absolutely HATE the SO-239 and PL-259 connectors. They are spec'd as UHF connectors but they are not 50 ohms at UHF, probably around 45 ohms. Mechanically, they suck too. They also do not provide a full 360 degree termination for the cable shield. I would not use one of these connectors above about 30MHz. They are far more trouble than they are worth. On a 440 ham repeater homebrewed from Icom UHF Part 90 mobiles, I did a little surgery on the transmit mobile and got rid of the SO-239 connector. I replaced the SO-239 with a length of RG142U coax coming out of the mobile with an N connector on the other end. The tricky part was getting a full 360 degree shield connection to the circuit board inside and to the radio's heatsink casting. The first thing I do on mobiles now is I put an N female to PL-259 adapter on the SO-239 connector on the mobile and then deal with nothing but N connectors the rest of the way.
  21. Motorola MSF5000, MSR2000*, MTR2000, XPR8300General Electric Mastr-II*, Mastr-IIIKenwood TKR-820 repeaterKenwood TKR-850 repeaterKenwood NEXEDGE NXR-800 (nice 5W 1U package for driving an external PA)Kenwood NEXEDGE NXR-810Vertex VX7000 series * = Depends on exact model, not all have Part 95.
  22. The OP says the radio is a BF-F8HP. That is a 3rd gen Baofeng UV-5R. Transmitting with it in the USA is legal ONLY on the 2m and 440 ham bands by licensed hams.
  23. What's your HAM callsign? You're aware that's a 70 cm HAM repeater, right? (not GMRS)
  24. DCS is transmitted at a rate of 134.4 bits/s. The DCS waveform directly modulates the FM carrier, with a logic 1 represented by a positive carrier shift and a logic 0 represented by a negative carrier shift. The FM deviation is about the same as CTCSS/PL. The DCS waveform's edge rates are carefully controlled to limit harmonic content to avoid generating audible harmonics. A DCS word consists of a 23 bit cyclic Golay code with 12 bit codeword (23,12) formed from the 12 least significant bits. The 11 most significant bits are error correcting code bits generated by the Golay algorithm from the 12 codeword bits. The 12 bit codeword consists of a fixed Octal 4 (100 binary) plus the 3 Octal digits that you can program. A DCS word plays out backwards over the air due to the least significant bit being transmitted first. A DCS word is sent repeatedly as a continuous low baud rate data stream. DCS/DPL has a specific turn-off code or reverse burst at the end of a transmission which resembles a 134.4Hz sine wave. In radio systems with a mix of CTCSS/PL and DCS/DPL usage, it is recommended to avoid using a CTCSS/PL tone of 136.5Hz due to the DCS/DPL kerchunk problem caused by the 134.4Hz DCS reverse burst. The time required to reliably decode DCS is slightly longer than CTCSS and is about 350ms or less. CTCSS typically decodes in about 250ms or less. When decoding DCS on very weak signals, the DCS decode threshold can be as much as 2 dB worse than CTCSS. From an end user perspective, these differences are way down in the noise (LOL) and it's hard to tell any difference. The average end user probably won't notice any difference in DCS/DPL vs. CTCSS/PL performance. DCS has its own set of issues to deal with. The long high and low bit times of the NRZ data can cause problems with baseline wander and cause decode problems. Distortion in the transmitted DCS waveform itself can cause decoding problems in the receiver. DCS is also sensitive to frequency errors in the transmitter and receiver. A signal transmitted with DCS received a few kHz off-frequency in the receiver impresses a DC offset on the recovered DCS waveform which causes the decoder to see a step function instead of the DCS data. This causes very slow decoding or failure to decode. Good low frequency response down to about 3 Hz in the modulator in the transmitter and in the discriminator output in the receiver are necessary for reliable DCS operation. IIRC phase modulated systems have trouble with DCS. True FM modulated systems tend to work better. Motorola trademarked the Digital Private Line (DPL) name. Other manufacturers have to call it something else. Digital Coded Squelch (DCS) is the generic name. You'll see mixed usage of the two names as I have used them above. If it's not a Motorola radio, it's not DPL. It's DCS instead even though it's exactly the same thing as DPL. Motorola originally implemented 83 DPL codes and manufacturers have expanded the set of codes to 104 codes. Motorola's 83 DPL codes have been implemented by all manufacturers but not all manufacturers have implemented the full set of 104 codes. Motorola's original set of 83 DPL codes have been fully vetted and are known to work well. Some of the extra codes making up the set of 104 codes may not work as well. YMMV. I've also heard DPL sometimes referred to as "Definitely Prevents Losers". LOL. I successfully thwarted a GMRS repeater jammer years ago with DCS/DPL so the jammer couldn't key my repeater. The jammer didn't have a clue about DCS/DPL nor did he have DCS/DPL capability in his antiquated equipment and only had CTCSS/PL. The jammer eventually gave up. This trick won't work anymore given that practically all manufacturers now offer DCS capability in their radios. DCS information: https://wiki.radioreference.com/index.php/DCS http://onfreq.com/syntorx/dcs.html http://www.repeater-builder.com/tech-info/ctcss/ctcss-overview.html
  25. The errors in the specs for the Retevis 900MHz radio isn't just a simple mistake or two. Many of the specs are incorrect and N/A for a FHSS radio. Here's some fact checking....blue text is mine. Overview on Retevis' website: Licensed by the Federal Communications Commission (FCC) and Industry Canada to operate in the license-free 900 MHz ISM (Industrial, Scientific and Medical) band. Okayyyy..... Designed for business operations, the DTR Series radio will free your time from regulatory paperwork and licensing applications and saving radio licensing fees. Are we talking about a Motorola DTR 900MHz FHSS digital radio or a Retevis 900MHz FHSS radio? The statement looks like a copy and paste from Motorola's documentation. Features: 1. 900MHz FHSS license free radio 2. Digital and analog compatible Support DMR digital and analog two communication modes to ensure that the original analog products smooth transition to digital products to meet different communication needs FALSE. Can't be both of these at the same time. An FHSS radio is not compatible at all with a conventional analog or digital radio. An FHSS radio won't use DMR either. 3. Digital signaling function Rich calling modes that support DMR protocol, including single call, group call and all call; supports remote inhibit function and other applications FALSE. It won't be using DMR if it's an FHSS radio. 4. Interference free, private communications Leverage Frequency Hopping Spread Spectrum (FHSS) technology for more reliable and private communication when compared to standard analog radios. This is TRUE! 5. High sound quality This digital two-way radio uses advanced AMBE +2TM voice processing technology to achieve higher quality PARTIALLY TRUE. The digital audio from a Motorola DTR radio and other digital radios is high quality. The AMBE+2 vocoder is for a DMR conventional radio, not for an FHSS digital radio. The Motorola DTRs use Motorola's VSELP vocoder. VSELP was used in Motorola ASTRO digital radios before P25 Phase 1 which uses the IMBE vocoder. VSELP was also used by iDEN phones on NEXTEL and other iDEN networks. 6. Prominent functional keys Programmable button can be used to quickly access call features like Call All/Page All, to talk to radios without searching through your channel list. The Call All/Page All refers to the Call All Available and Page All Available features in the Motorola DTR600/700 radios and Motorola DLR1020/1060 radios. The legacy DTR410/550/650 models (now discontinued) don't have the Call All/Page All features. 7. Supports the use of repeater PARTIALLY true. FHSS radios such as the Motorola DTRs are simplex only and occupy the entire 902-928MHz band when they transmit. There is a repeater available for them ($1500) but it does not function like a conventional repeater. It consists of a pair of DTR radios running custom firmware and a controller to behave as a repeater. Each DTR radio uses a different frequency hopset. DTR radios talking on one hopset can talk to DTR radios on the other hopset using the repeater, and vice versa. It is one way operation at a time. The repeater has to be carefully placed to extend coverage areas. It is usually located where there is some overlap between an existing coverage area and the desired extended coverage area. The application for this is to extend coverage areas inside large buildings. Some on-site business systems use the 900MHz band, including the Motorola DTR 900MHz FHSS frequency hopping spread spectrum handheld radios, which operate at 1watt ERP transmit power on the 902-928MHz ISM band using frequency hopping digital voice. Current examples include the Motorola DTR600 and DTR700 radios, These radios operate with 50kHz channel spacing and 8-level FSK digital FHSS. 902.525MHz to 927.475MHz coverage. Mostly true. This statement reads like marketing literature. An FHSS device operating in the 902-928MHz band is required by FCC 15.247 to use a minimum hopset of 50 frequencies and with a maximum output power of 1 W (+30 dBm). The Motorola DTRs operate at 830mW (+29.2 dBm) to 890mW (+29.5 dBm). The measurement of transmitter output power is a conducted measurement made at the antenna connector. Output power is not specified in terms of ERP or EIRP. The 50kHz channel spacing refers to individual frequencies in adjacent hopsets, NOT individual frequencies within a given hopset. The Motorola DTRs have 10 hopsets available, consisting of 50 individual frequencies, spaced 500 kHz apart. The 902-928MHz band has 26MHz of spectrum and gives 52 frequencies spaced 500kHz apart. The first and last frequency is not used due to being at the band edges so that leaves 50 frequencies available in a hopset. Frequencies in adjacent hopsets are offset by 50kHz. The spec'd 902.525MHz to 927.475MHz coverage is correct for the Motorola DTRs. The mention of the 8-level FSK digital modulation for the FHSS operation is correct for the Motorola DTRs and refers to the modulation used on each hopping frequency. The occupied bandwidth of the 8-level FSK modulation on a given hopping frequency is wider than what a narrowband receiver will accept, even if you were to stop the FHSS and have the transmitter sit on a single frequency. Technical specs on Retevis' website: A mixture of DTR, DMR, and analog specs (LOL). At least they got the DTR freq range right! Main technological specification Frequency range​ 902.525 - 927.475 MHz​ Channel Capacity​ 30/50CH (up to 200)​ Channel Spacing​ 25KHz/12.5KHz​ Operating Temperature​ -25℃~+60℃​ Operating Voltage​ DC 3.7V​ Antenna Impedance​ 50Ω​ Microphone Impedance​ 2.2KΩ​ Battery​ 1800mAh​ Dimension​ 128×54×32mm (No including antenna)​ Weight​ 223g​ Freq range: Correct for the Motorola DTRs. Channel capacity: Channels in the Motorola DTRs refer the number of public talkgroups or Profile ID talkgroups that can be programmed. The "up to 200" refers to the maximum number of private contacts that can be programmed for setting up private talkgroups and for private 1 to 1 calling. This is NOT the RF channel capacity like in a conventional radio. Channel spacing: Incorrect. This is the channel spacing for conventional analog and digital radios in wide and narrow bandwidths and is N/A for an FHSS radio. Transmission Output power​ 1W​ FM modulation​ 25/16K¢F3E 12.5K/8K¢F3E​ 4FSK digital modulation​ 12.5KHz for data:7K60FXD 12.5KHz for data and voice :7K60FXE​ Vocoder type​ AMBE++or SELP​ Digital Protocol​ ETSI-TS102 361-1,-2,​ Harmonic​ ≥70dB​ Signal-to-noise Radio(wide/narrow)​ 25K≤-45 dB 12.5≤-40 dB​ Rated audio Distortion​ ≥5%​ Frequency Stability​ ±2.5ppm​ Max Frequency Stability​ 12.5K≤-40dB​ Output power: Correct. FM modulation: Incorrect and refers to conventional and analog radios. N/A for FHSS digital radios. 4FSK digital modulation: Incorrect. Refers to DMR digital modulation for conventional radios. N/A for FHSS and the Motorola DTRs which use an 8-level FSK modulation scheme on each frequency in a hopset. Vocoder type: Incorrect. AMBE++ is used by DMR. SELP = ? The Motorola DTRs use Motorola's VSELP vocoder. Digital Protocol: Incorrect. The ETSI standard listed is for DMR. N/A for FHSS analog or digital. SNR (wide/narrow): Incorrect and N/A for FHSS. The spec is for conventional radios. Reception Sensitivity (12dB SINAD)​ Analog 25K≤-121dB 12.5K≤-119dB​ Digital 0.3μV/BER5%​ Signal-to-noise Radio​ 25K≥45 dB 12.5K≥40dB​ Adjacent channel selectivity​ 25K≥65 dB 12.5K≥60dB​ Intermediation (Wide/ narrow)​ 25K≥60 dB 12.5K≥55dB​ Spurious Response Rejection​ ≥65 dB​ Audio power​ 1W​ Audio distortion​ <5%​ Frequency Stability​ ±2.5ppm​ Battery life under 5-5-90duty​ 14.8 hours(with 1600mAh Li-ion battery)​ 20.9 hours(with 1600mAh Li-ion battery)​ Sensitivity: Incorrect. The spec listed is for conventional wide/narrow operation. N/A for FHSS. SNR: Incorrect. The spec listed is for conventional wide/narrow operation. N/A for FHSS. Adjacent channel selectivity: Incorrect. The spec listed is for conventional wide/narrow operation. N/A for FHSS. Intermodulation (intermediation LOL): Incorrect. The spec listed is for conventional wide/narrow operation. N/A for FHSS. Spurious Response rejection: N/A for FHSS. The Bottom line: EPIC FAIL. Too many glaring mistakes with specs which are N/A and incompatible with FHSS operation. I have to call BS here and say this radio is Vaporware. There were some analog 900MHz FHSS radios made by TriSquare a number of years ago. These were the eXRS radios and were marketed as an alternative to FRS. They operated on 900MHz and used FHSS. The similarities with the Motorola DTR radios ended there. The eXRS radios were analog and used a hopset of 50 frequencies per FCC 15.247. They spent 400ms on each frequency in the hopset, the maximum accumulated dwell time allowed per FCC 15.247. This meant they hopped very slowly and you could sort of monitor them with a scanner if it was fast enough and only scanning the specific freqs in the hopset. Using a divide and conquer approach by employing multiple scanners with each scanner covering a portion of the hopset worked better. You would hear the audio ping pong between multiple scanners but at least you could sort of monitor the eXRS radios. The eXRS radios were notorious for synchronization problems and took a long time to re-sync if synchronization was lost. The bottom line is these radios were total JUNK and the company is out of business. OTOH, the Motorola DTRs are professional quality and 100% digital and packed with features and work amazingly well. The DTRs spend no more than 90ms on any given hopping frequency, which works out to around 11 hops/second. The fact that the DTRs are completely scanner proof comes as a bonus. I have been on the 902-928 band on 33 cm ham repeaters. The Motorola DTRs operate perfectly fine and coexist with everything else transmitting in the 902-928MHz band. The FHSS operation allows them to peacefully coexist with everything else in the band without interference. Unlike conventional radios they are VERY difficult to jam due to the FHSS operation.
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