Radioguy7268

It's worth repeating. If you're running a compact "flat pack" duplexer - and you're pumping out over 20 watts, there's a real good chance that your system's measured desense is 1.5 to 2 dB. Seems like a small amount, right? However, if you can improve your receiver performance by 3dB -you have effectively doubled the area of coverage that your portables can talk back in from. One of my first Ah-Ha! moments in 2-way radio was when an old timer took me out to a tower site where a customer on the repeater system was complaining about poor coverage with their hand-held portables. When we got on site, he spent a bunch of time setting up his test equipment and taking measurements. He already knew what he was going to do, but he took the time to educate me. He showed me the performance of the system as it was and showed me the measured desense. He let me listen in to "weak" portables that were operating on the edge of the system. The customer had been sold a brand new high power 100 watt "high performance" repeater, but was running it all through an existing flat pack 6 cavity notch duplexer. They spent their money on more POWER, not on the duplexer - they already had one of those. Long story short, after showing me the system performance as it was - he turned the power down to 10 watts. Suddenly, the units "on the edge" were coming in much more clearly, and users that had not been able to get in at all were now using the system, but still were scratchy. He then added a tuned bandpass cavity between the duplexer and the repeater's receiver, and WOW, now they ALL sounded good. Then he went back and showed me what zero desense looked like. Couldn't even see a difference in the noise floor when the transmitter was keyed up locally. Now the repeater had good ears - an ability to listen that matched it's ability to talk out. Balance.

Yes, it is bad. You'll probably create massive desense in the receiver, and do nothing to create robust repeater coverage. Want to improve repeater coverage? Improve receiver performance. 9 times out of 10, that's where the system is lacking. Horsepower makes all the headlines, but there's more to the story when it comes to real world performance.

... and some sellers will include basic programming for free w/ purchase. The trouble is that most used radios in the $30 to $40 range will not include fresh batteries, and with Vertex, you need to make sure that you have a battery that will match up with the charger.

You would also have to realize that in order to bump up your transmit power by just 3dB - you would need to double the transmit power up to 36 watts. How high did you plan to go? Is the transmit power where your system is lacking? The old GMRS rules specifically ruled out using external power amps. Not so sure that the newer revision still does. You also need to realize that most cheap amps will amplify noise as well as signal across a broad range. In short - if you're throwing off some spurious birdies - the amplifier is going to increase those spurs as well as your desired frequency. It's not going to make you popular with your frequency neighbors. As BoxCar said - invest in a higher power mobile if you truly need more power. Or just get a better antenna. Or better coax. You're probably losing 1 or 2 dB just in your cheap coax - not to mention any poor connectors or adapters you might be using.

Count me as not being a fan of Bridgecomm. It's just two mobiles in a box. They used to use Maxon mobiles, not sure if they still do. My direct experience with Bridgecomm was getting called in to troubleshoot a Hotel's repeater. Unit had been in service less than 3 months, and the original seller had walked away from it, telling the Hotel that they were on their own. The trouble described was that the repeater was "intermittent". When I arrived, I quickly diagnosed that while the repeater was functional, it was having trouble with the receiver. If I kept a strong -85 dBm signal generated directly into the front of the receiver, it worked well, but once the signal level dropped below that, the repeater would drop. Much further diagnosis led to this only happening with DPL - regular Tone PL codes carried through to -110 dBm. There was also about 3dBm of desense in the unit, so a receive signal on the edge of opening the repeater would quickly lose out once the transmitter kicked in, leading to the repeater cycling back and forth, and the customer's complaint of an intermittent operation. Phone calls to the company for tech support were quickly answered, firmware upgrades were emailed, problem persisted. The duplexer was eliminated, the trouble still continued. Bridgecomm technical support suggested re-programming the customer's entire fleet to eliminate DPL. When we asked if Bridgecomm would be paying for the cost to reprogram the fleet - crickets. After 3 weeks of back and forth, the repeater was returned to Bridgecomm for a partial refund and the customer purchased a new (at that time) Motorola XPR8400 repeater, and the problem disappeared. No portables were reprogrammed. I suppose I could have just played nice and reprogrammed the entire fleet to Tone PL, but I didn't like the internal desense - which would have still been present even on Tone PL. To me, that's just poor design. An acceptable level of desense in a repeater is Zero. That's been my only direct experience with the brand. I don't know if they've greatly improved since.

There were 2 versions of the R1225 made. The "High Power" version did 25 (low) or 40+ watts (high). Don't run an R1225 on high if you want it to live. They're famous for burning up. The high power versions are pretty easy to distinguish because they've got a pretty large set of cooling fins as compared to a typical MaxTrac or GM300 mobile. Model number M44GRC90C2AA. The lower power versions would run from 1-10 watts. They had a smaller set of cooling fins - similar to a typical Radius mobile. Model # M04GRC90J2AA If you have the 1225 CPS Software, and the proper equipment, you can tweak the radio's output power for the high/low settings, but I wouldn't recommend going below 23 watts or so on the High power version. Trying to put it down to 15 watts is asking for trouble. Repeater-builder is a great resource for Motorola repeaters. http://www.repeater-builder.com/motorola/gr1225/gr1225-overview.html

50 watts is probably overkill if you're talking about just covering 400 acres in a valley - and you're planning to talk back into the repeater with 4 or 5 watt portables. Less power is more forgiving if you're planning to use solar. You'll be able to get away with smaller panels, fewer batteries. A trailer setup sounds like a good way to do a temporary site, and have the ability to move it around to find your sweet spot - a combination of sun/coverage. If you're trying to cover a smaller area using portables, I like the idea of a Unity gain antenna. Especially if you're not up on the top of the ridge. Top of the ridge would probably give you the biggest bang for the buck for total coverage area, but you might over-shoot your desired area of coverage down in the valley. As far as equipment - do you want new? or used? Quality new repeaters from Motorola or Kenwood are pretty tough to come by in today's semiconductor shortage world. Used is still available. CCR's are still available. Do you plan to put everything together yourself, or are you looking for a local provider who can do all the work? Final note, the price difference in licensing between GMRS and a 10 year Business/Commercial license is negligible compared to the overall cost of equipment. GMRS might be good for what you want to do, but a Business/Commercial license covers more potential users, and has more available channels - with Frequency Coordination. That doesn't guarantee you exclusivity, but in a rural area, there's a pretty good chance you'll have a business frequency that's not being used the next town over, and not having to share space with FRS equipped hikers/hunters. A Business/Commercial License would also allow you to run Digital and enable Privacy/encryption - which you can't really do in GMRS. Good luck with it.

If you can stick with CPS 16, then you're much better off to stick with using that. As for the CPS software's 3 year subscription - that allows you to access and download new versions of CPS for the next 3 years. Generally, there's a new update every 6 months or so - along with Firmware updates. CPS Software, once downloaded, is yours to use. There's no stop date built in, other than the fact that newer radios with newer software will not be able to be read/manipulated with your older, outdated software at the end of 3 years. The problem for subscriptions has more to do with Motorola's new SUM or Software Update Management - which is really more towards the Firmware side of things. New radios come from the Factory with a 5 year Essential Services/SUM included - so 5 years worth of Firmware updates are included along with the Warranty on brand new radios - which is kind of important if you're trying to keep an entire fleet operating with features like enhanced GPS, Cap Max trunking, or Indoor Location. After that initial 5 years of "free" is up, you would not be able to do Firmware updates to keep the radio current with the latest releases of features - unless you pony up to get a new SUM subscription - which will run in 3 year terms. Confused yet? Motorola's vision is that they're really a Software and Services company - and they're no longer satisfied to sell equipment which might last 5, 10, or 15 years - and only make a profit on that one-time sale of equipment. They want to generate a revenue stream that is continuous, and try to tie the operation of features and services to the equipment. I don't think most hobby folks are going to want to play in that arena, but I've been wrong before.

Never say Never - but for most practical purposes, yes. Once you use CPS 2.0 to write a codeplug into a radio - you're pretty much locked into it going forward, unless you're into hacking and cracking, and using illicitly obtained software that voids your warranty. For a hobby based user, there is no practical purpose to using CPS 2.0. If you're already using CPS 16 build 828 - stay there. Firmware R 02.09.0001 is the most recent version that will still work with CPS 16. Most of the newer CPS 2.0 Firmware updates require you to have an active SUM (Subscriber Update Management) - which generally means if your radio is more than 3 years old - you need to purchase a SUM License just to upgrade firmware. Not really worth it IMHO.

Ordering new equipment right now is an exercise in patience. Beyond the painfully slow interface of shop.motorolasolutions.com, you're entering into a time delayed backlog of immense proportions. You would also get a new unit that requires CPS 2.0 for programming. Do yourself a favor, grab a slightly used XPR7550e for half the price and half the hassles - and then you can use CPS 16 build 828 (which is the last CPS version before CPS 2.0 was introduced.)

You cannot use Chirp for programming an NX-1300. You need to use the Kenwood KPG-D6NK software, which should be a free download. However, you can't use the software until you purchase a $100+ License Key which will be specific to a single PC. Once you have purchased the Key, you will need to Authenticate the software on the exact PC that you plan to use. I have not yet used the Kenwood NX-1300 on GMRS, but I believe that the standard License will be Narrowband only. There's a process to go through in order to allow Wideband to be enabled. The NX-1300 is either Analog, Analog + DMR, or Analog + NXDN. Make sure you've got the correct radio firmware for what you're trying to do. You can enable different Digital modes by purchasing a License and enabling the correct firmware. Having a sample codeplug to work from should help you to figure out the Kenwood setup. It's a fairly simple frequency table setup for most of the Analog information. Digital becomes a bit more complicated. You will need to load any Voice Files into the radio before you can assign those to any channel locations or button functions. Kenwood offers some training videos online through their Kenwood University online. Those are Dealer Training videos on the MyTools site. Not sure if there's any access available to anyone who is not a dealer, but I'd start by asking the place where you bought the software to point you in the right direction. Good luck with it.

Just a clarification. Un-related parties would need to have separate licenses, but a family business could certainly operate all under one License/Call Sign if all parties are close relatives - ie: Father/son business, family farm, etc. I mention this because I know of a few relatives who operate a family farm and use GMRS for their operations. 100% legit with just one Licensed call sign. As mbrun mentioned above, the loss prevention team is likely operating FRS radios at 2 watts, which probably works for them, and they don't have a clue that anyone operating on GMRS could step all over them. If that isn't happening, it's kind of like the proverbial tree falling in the forest.

60 ft is difficult without a building/tower/structure to lean on - or some guy wires. I've done some 40 ft. utility poles with 10 ft. mast, and I can tell you they do sway and move in the breeze, even with just a simple fiberglass omni, but they work. Forget the fiberglass telescoping fishing poles. More than 10 ft. of unsupported pipe/mast is asking for trouble. You might get away with it for a week, a month, a year, but you won't last through the first decent storm. If you plan to use mostly portables - you will probably need to 'de-tune' the receive side sensitivity by a few dB in Radio Mobile to reflect real world conditions of fade, foliage, and poor portable positioning. I haven't seen too many hobby type repeater systems at 50 or 60 ft. that would receive a portable reliably at 30 miles. I usually figure portable coverage will be about 50 - 60% of what a high powered mobile would be. You might be able to key the system, but you'll always know when someone is working a portable at the fringes. I believe the standard receive side sensitivity for Radio Mobile is set @ .45 uV - which is right around -114 dBm. That's a weak signal, but most decent receivers can operate below that level, you just won't have full quieting. I'd want a Portable coverage map that represents something closer to -110dB for modeling on-street coverage, which would be @ .70 uV

The XPR8400 is decent, but it is nothing more than two XPR mobiles in a box. The transmit brick has an extra set of fins attached to aid in cooling, but I wouldn't call it 100% duty cycle at high power. I wouldn't even call it 100% duty cycle at 25 watts, but I wouldn't be scared to run one for GMRS at 25 watts for 2 or 3 hours of transmit time per day. If you're looking for something smaller that will truly run 100% duty cycle at high power with digital capabilities, check out the SLR5700. I have yet to replace one of those because it burned up. If you want something for GMRS that's similar in price to the XPR8400 and is truly 100% duty cycle - check out the analog MTR2000.

9dBi is really 6.5 dBd of actual gain. 6 dB is nothing to sneeze at - but for the "what am I going to get by moving up the antenna?" question - the best thing to do is model your system. Radio Mobile is the go-to for an online tool that's actual useful and doesn't take more than 30 minutes to figure out the basics. Radio Mobile online coverage map Once you've mapped out your proposed initial system, you can toy around with it to see what you're going to be able to cover given certain heights and gain. If you make the areas where you need it to work at 25 or 30 foot, and there's no appreciable coverage gained by moving to 50 ft, then you know it's probably not worth the trouble. If you're still not covering where you want at 50 ft - then start moving upward until you see the coverage you desire. Hint - 5 or 10 ft. height difference usually doesn't do that much. I've found their coverage predictions to be fairly accurate if you push the desired reliability to 99% and use realistic figures for your wattage & losses. The antenna height should usually be figured as half the total length for a vertical omni.

My understanding is that the DRX units use cabling between the two units for TX/RX isolation - not for coverage. They supply you with a 20 ft. cable - not a 200 ft. cable. They offer an optional 50 ft. cable if the 20 ft. cable doesn't allow enough separation. From the installation instructions: Theoretically, you could probably find a spot where the receiver location of the DRX would allow you to "get in" - but the TX back might not reach you. I'd think that those instances would be very rare in the real world.

My understanding of the newest wiz-bang AT&T provided FirstNet LTE is that there's simply NO provision for radio to radio simplex in the Voice over LTE protocol. All conversations must go through the network backbone. I believe their concept is that since they're building a "hardened" backbone, it's not supposed to go down. There are other Public Safety systems that want to force every conversation through a repeater because it makes central control and recording of all calls possible. It also means that a "lost" radio can't be used if it's killed/stunned on the network. If you allow the radios to run simplex, who knows where it might migrate to? Not how I would run a multi-million dollar public safety system, but then again, nobody is tossing me the keys and asking me to run one.

Look in the "Radio Wide Configuration" - Make sure that the CWID option is enabled in the General Option tab, then switch over to the: CWID Signaling tab Once you're in the CWID tab - make sure that CWID Operation is set to "Only with repeater activity" - then set your time interval (10 or 15 minutes) - and I'd recommend using PL strip along with the "Interruptible by PTT" setting. Good luck with it. R1225's are famous for burning up the PA if they're run on full/high power settings - even when you don't think you're close to the advertised 50% duty cycle. I'd recommend making sure that the fins and fan are clean & setting the unit to low power with 25 watts or less out of the repeater. Use an external amplifier if you really think that you NEED 50 watts out of the transmitter (you probably don't.)

I would agree. Allowing any type of automated GPS updates will kill channel capacity even if you've got just 5 or 10 high power units reporting GPS location every 30 seconds. I haven't looked deeply enough at the rules - but is the FCC requiring units to monitor the channel prior to transmitting their "brief" data burst? Automated location updates on repeater channels would be a disaster. I can see a point to allowing units to update automatically once every 10 to 15 minutes - or alternatively, tagging on to the beginning or end of a voice transmission like a PTT ID.

I do most of my CDM programming nowadays with a cheap USB cable. I've got the RIB box, but it's really only necessary when you're trying to do a Flash update for firmware. There are plenty of other "gotcha's" involved with programming though - and I'll agree that a real RIB with a genuine Serial port is your safest starting point. The audio quality on the CDM's is good - but I like them much more for wideband than narrow. The 12.5 narrowband always seemed to be lacking for volume - even if you jacked around with the gain control, audio compression and compandering. The newer XPR units seem to have better 12.5 analog audio - right out of the box.

A CDM radio is not Part 95 Type Certified. The CDM radios (and the matching HT portable series) are Part 90 Commercial. I'm of the mindset that Part 90 meets and exceeds all standards for Part 95, and it appears that the FCC agrees: https://transition.fcc.gov/oet/ea/presentations/files/nov17/54-Part-95-Misc-Eqpt-Filing-r1-TH.pdf So if you don't want to use Part 90 equipment, that's up to you. You're never going to find an example of the FCC fining someone for using Part 90 equipment, and you've got their own words above that basically say that their intent is NOT to prohibit users from operating with Part 90 equipment on GMRS. I'd use a CDM radio for a base - but like Steve says above, you want to get the "mid power" version if you want to operate at lower power levels. There's a ton of information on the CDM series over at repeater-builder.com . Beware of Ebay refugees if you're looking at CDM radios. There's a bunch of hacks that people used to take the LS trunking models and flash them into Conventional configurations. Done right, there's nothing wrong with using one of those - but done wrong, you're just buying a headache.

Except the person you're talking to on 462.xxx simplex is still going to hear you if you're using a repeater to talk to someone else when transmitting on the high side of 467.xxx (PL mask or not, you're still on that repeater's output frequency.) There's no "extra" channel capacity - unless you're on the very fringe of a repeater's coverage area, and counting on the FM Capture effect of your stronger local Simplex signal over-riding the weaker signal of the distant repeater. Even then, any other user in your local area is going to be either listening to you, or waiting for you to be done before they can effectively use the channel for their conversation. You might segment people into talkgroups via PL based fleets or subfleets, but you don't gain any channel capacity. In short, I agree with the 22 channel comment.

Turn the radio over (smirk). But seriously, yes. That's what you do - but then you unscrew the front control head - turn the display right side up, and screw it back on. It was designed to do that. Alternatively, you can hook up an external speaker & put that anywhere that's convenient.

Yeah, the big advantage is having one radio that acts like 2 (portable on the belt, mobile once you're clicked into the MVA dock). When the radios are "subscriber" based, meaning that there's a fee associated with having an ID on the system - or if certain radios get enabled with certain features/talkgroups - that's when it's a lot easier to just have Trooper A plug his portable into Vehicle X when he's driving that. Or do the same when he switches over to Vehicle Z. That way, no matter what he's driving - when he keys up, he's still showing as Trooper A on everyone else's radio.

I don't have any personal experience with using one. I've seen a few. Pricing for new runs north of $1000 - and you still need to get it installed. What are you looking to do with one? For GMRS use - I'd tell you that you can buy a decent 40 watt mobile for a bunch less than buying a new MVA docking station. They also take up more dash/console space than a remote mount mobile.