Radioguy7268

Search up the Rodinia 2.3 chip used on some EVX & XPR Gen2 radios. That is a 12dB SiNaD reading I'm quoting for that -120 dBm - and it's easily achieved with those Rodinia receivers. Fully quiet at -120 dBm. I'll agree that real world factors play into this stuff. Noise floor is the killer in most urban environments. There's a ton of trash and hash out there in the real world. Nobody is designing a commercial system around the theoretical basement level of what receivers can do. Previous forum discussion on Receiver design

Yeah - the -120 dBm of the assumed average receiver is the true limiting factor. Google up EME (earth moon earth) contests - people using the moon to bounce/reflect signals. I've heard of people making it with 2 watts or less, but they're jacking up the receivers with all types of high end pre-amps and using CW. Voice would be problematic. There are real world receivers out there in UHF radios (Think DMR Digital Vertex EVX & Moto XPR's) that will go down to -125 without spending too much money (and still have decent selectivity). Those radio on a chip direct conversion receivers all the CCR folks love have some wild receive sensitivity, but they're also about as selective as a drunken politician spending someone else's tax dollars. The original Apollo comm's with the moon were all UHF with Yagi antennas. People still heard "One giant step for mankind" although how clear it was is debatable. Then again, those Flat Earther's would point to the limitations of UHF radio signals as proof that the landing did not take place on the actual moon. AI makes my eyes hurt.

I read about the rash of robberies happening to GMRS users, so I started using FRS instead. /s

Glass mount antennas suck for UHF. They are marginally better than using a portable inside a vehicle, and I do mean marginally. 800 & 900 MHz work better, but still not ideal. I'd tell you to look for other options before spending money on a glass mount. A 6" UHF hatpin can be mounted in plenty of locations where it's barely noticed. Shark fin antennas made by Stico & others mimic factory FM antennas for the entertainment radio.

I've got a concrete ready-mix company in the Mid Atlantic area with over 100 trucks using M1225 and PM400 radios in their fleet. They've been a customer since 1998, and they're still using some of the original radios that we sold to them. They go through palm mics & external speakers (which get clogged with concrete dust) but the radios sit in trucks that are parked outside all the time. They see temps from Zero to 90 every year. They get about as much use and abuse as any radio I've ever seen, and the M1225/PM400's are nearly bulletproof in my experience. The M1225 is Part 95 type accepted. The PM400 is not, but is just the updated version. Either one can be bought used all day long for prices similar to any of the CCR models listed above. Many sellers will program them for you.

There are 2 different radios being discussed here: The M1225 LS model was built by Motorola as a UHF Trunking radio that had the ability to program conventional channels in addition to LTR (Logic Trunked Radio) channels. There was no add-on board in that radio. The standard M1225 UHF mobile radio only did conventional channels out of the box. You could use an add-on Option Board (most made by Scholer-Johnson, but sold by others) to add LTR Trunking capability to the standard M1225. Removing the board (or just disconnecting the flex cable to the LTR board) would revert the radio back to conventional mode. The Scholer Johnson add-on board would be in the top left rear of the radio under the housing & secured with 3 nylon screws.

You would need to download and use RDAC (Remote Diagnostic and Control) program in order to see the internal repeater logs. The "logging" in CPS is software validation - nothing to do with operations. It just logs changes in the software & read/write operations. If you programmed the unit with CPS 2.0 & it was originally set up using CPS 16, you probably should have updated the repeater firmware prior to 'upgrading' to CPS 2.0 Assuming you read & saved the original log - go in and look at the Codeplug & Firmware info on the original codeplug, as well as the 'last programmed' date (which should be the last time it was set up prior to you touching it.) If you've got really old firmware in the box, that may be causing you some of your issues. A basic GMRS repeater does not need half the functions available in DMR. Keep it simple. Just add a new analog channel, then delete any previous channels, and program that new Analog channel with your basic channel info. Leave CWID and any other settings off for now. I'd be a little concerned if you had to 'blow the dust off' of a unit. That makes me think the machine was in use for a while without ever being touched or upgraded. The XPR's are a fine set & forget machine in typical single user campus type applications. They're not a high end repeater designed for mountain top use at RF dense locations for 24/7 operation. They are really just 2 basic XPR mobiles in a box with some special interfacing.

SMR's were the original business band analog trunking systems in the 1980's. You probably need to do a deep dive if you plan to try to build out something using 800/900 MHz freq's. Most of those original SMR's were bought out by Nextel (which implemented a digital cellular-like technology known as iDEN, and operated under an FCC waiver as an eSMR - enhanced SMR). Almost all of those old SMR freq's now belong to Tmobile. There's some limited Licensing opportunities in 800 MHz for smaller businesses, but it's a pretty steep learning curve to figure out what's available in your area, and what it might cost you to get up and running.

Nothing stops an individual from being in the 'wireless' business, and renting repeater airtime (or even airtime without a repeater!) to Part 90 eligibles (which is pretty much anybody except the Federal Government). You don't need to open your books, you don't need to claim a profit, and you don't need to prove much of anything to anyone, other than proving you can pay the Licensing and Coordination fees up front. Although, you would need to file a Construction Notice and certify that you're up and operating on the frequency(s) within a year of the License grant.

I was coming into this & expecting to tell you to use the LS version software, but seems you've already got that. Makes me wonder if the radios are actually standard M1225's with an LS housing snapped on ? Can you compare the model number to the radio that does read/write? I've also heard of some folks snipping the mic jack leads to keep people from messing around with 'their' programming. Take a minute or two and check that out if you bought the setup already programmed by someone else. You should also check the mic jack connection to make sure they are clean and not corroded. If the repeater was sitting without a palm mic plugged in the jack, it's possible that it's just dirty and not making a good connection.

I should also mention that if you have really old XPR8300 firmware, setting up your channel in Dynamic Mixed Mode will NOT allow for CWID to go out at all via the repeater. Set up a single channel as analog only - remove/delete any DMM channel, and CWID should work. If you plan to use it for GMRS, you probably shouldn't be using mixed mode. If you truly want to use DMM, you shouldn't be using a first generation XPR8300. Those had limited feature sets and limited memory. The later XPR8400 was the improved version.

Those settings will work, but you need to have the unit set as a repeater. If you use an external controller, you're probably setting it up as a Base, and allowing for external control of the repeat function. I'd strip PL for CWID transmit.

Motorola also makes the DLR version of 900 MHz license free radios. You may find some newer ones sold under the 'curve' designation. DTR's are expensive for what they are. Even the older DTR650 radios still carry a price tag when sold as used, working units. What's your budget? There are also some folks using older Nextel units on just the "direct talk" feature - and they're usually cheap since they no longer work with any cellular providers. Look for something like an i355, but realize there is zero support and zero cross-communication with anything outside of another Nextel unit.

The transmit light should come on. That's normal operation for a repeater that's being keyed with a hand mic. If you have a receiver (portable) listening on the 462.675 - then put it in Monitor (disable the PL tone). If your repeater is transmitting on that frequency, you will hear it. Even if the repeater has a bad amplifier, or the duplexer is totally hooked up wrong, you'll still hear the output if you're in the same room with a portable listening on 462.675 If you can't get that - then you are NOT transmitting on 462.675. There's a limit to the amount of help you're going to get online. At some point, you need to be able to troubleshoot step by step & figure out what you have, and what you don't have. Throwing darts at a virtual dartboard for tech help is not the answer.

According to that picture - your repeater is set to 467.675 Receive - but with a tone of 77.0 Hz. I believe you said your portable had a tone of 127.3 ?? The repeater needs to have the same PL tones as the portables. Your transmit appears to be set to CSQ (no tone at all) with a frequency of 462.675. If the portable radio you are using is set up with a PL on the receive, you would not hear the repeater. (You should still see a 'busy' LED when the carrier comes up on channel). It appears your frequencies are correct - but you need to match your tones on your portables and your repeater. If you can key the repeater with a local mic plugged in - the repeater will just be transmitting on the base of 462.675

If you have the programming software & can read the repeater, then you have pulled the codeplug already. If the information programmed into the repeater is what you requested at purchase - and your portables are programmed in the reverse (Portable transmits on 467.675 & receives on 462.675 with a matching tone of 127.3) then the programming would appear to be correct. Double check frequencies in the portable. I will assume that your two portables will communicate with each other on a common simplex channel (ie: 462.675 for both transmit & receive). If that's all true, then I'll say it once more - call the seller & see what they advise.

I would be asking the seller for some help. It sure sounds as though the repeater has not been programmed to your frequencies. If you key up on a base mic attached to the repeater, you should definitely hear it on a nearby portable set to CSQ (Carrier squelch) - even if the antenna/duplexer is totally wrong. Even if PL tones are incorrect, you should still be seeing carrier activity on the LED's. Pulling a codeplug is probably the easiest way to figure out what's going on, and less trouble than boxing it up & shipping it back & forth. Ask the seller for assistance.

What is the EXACT frequency for the repeater's receive?

What frequencies are the portables programmed to? Even if the tones are incorrect, a transmission on the repeater's receive frequency should show as an active 'RX' light on the repeater when keying the portable. If you're not even getting that, then something is drastically wrong. The VXR7000 is fairly straight forward, and I'll assume the repeater (and duplexer) were tuned to the frequencies you specified at time of sale. Do you have the ability to pull a codeplug for the repeater?

You're not going to be able to buy the software for that from Motorola. That radio is about 30 years outside the Factory support window. There's a few different places online where you can find Radius mobile RSS available for free download, but you'll need to run something like DosBox to emulate a really slow old 386 PC processor. Hamfiles is where I'd probably start looking for the software. You should probably also get familiar with the Repeater-builder.com Radius and Maxtrac Mobile page

You are correct - and this specific problem is probably worse with GMRS than 'coordinated' Part 90 systems. However, the Linking issue can make the problem much worse over a much larger area. This exact issue would be part of the reason why people should read the "You just got your license, now you want to put up a repeater?" sticky - and then understand why overlapping coverage is usually less than ideal, and should be avoided. Still, there's a difference between me putting up a machine that I know might be lacking in coverage and still making best attempts to monitor before transmitting (up to and including monitoring the output freq. at my repeater site, in order to disable my repeater when a co-channel user is on the air), and me putting up a linked machine that by default says I don't care about your conversation, mine is somehow more important. If there are linked networks that are monitoring somehow, I'd still be interested to hear about it.

For anyone advocating for the use of AllStar or similar Linked repeaters, I've got just one question that sidesteps all the issues regarding networking and "wireline" definitions: How are you monitoring all those remote links for local non-linked traffic prior to keying up all repeaters in your network? What are you doing to avoid stepping on active local conversations that are not happening on your linked network, but are already taking place on non-linked repeaters? Monitoring for traffic prior to transmitting is one of those bedrock assumptions in the shared service frequencies - at least in any conversation I've had with FCC types. If your linked network routinely tramples on someone else's active conversation, I don't think the FCC would care if you're using microwave, Internet, or the Public Switched Telephone Network for wireline links.

If it was already written with CPS 2.0 - then there's no going back. (Well, there are ways, but nobody wants to send a rookie down that path!) Good news is, if they already did the updates & got it to 2.0, then there's little harm in using CPS 2.0 to make the changes you desire. You will need to activate that EID for the software in order to write a wideband frequency back into the codeplug. Hopefully someone already walked you through that part. You have a much better repeater than a Bridgecomm in my opinion, and I wouldn't get too worried about writing to it with CPS 2.0 The troubles come if you take something with really old original firmware & try to write it with the latest/greatest. Sounds like Used-Radios already did the work to get you up to date.

The XPR8300 is very first generation for the TRBO series repeaters. It's really just 2 XPR mobiles in a box, with some specialized hardware connecting them, and specific firmware loaded into the mobiles to allow them to act as a repeater. The XPR8400 was the 'improved' 2nd generation unit with more memory, more features, and a better cooling fan configuration. There is no option for an analog 'courtesy tone' in the standard XPR8300 configuration. You can get that courtesy beep if you add on an external control panel. Assuming that you have CPS 2.0 from Motorola with the Wideband EID - I would not bother to mess with the repeater other than pulling a codeplug & storing that copy for future reference if you might ever need it. It might be a good idea to also grab the MotoTrbo "Tuner" software & use that to read & store the tuning settings for the repeater just in case. There is absolutely no advantage to 'upgrading' the XPR8300 to CPS 2.0 If you have a working machine, and it does what you need, I'd really think twice before trying to touch it with anything above CPS 16. There are wideband enabled versions of CPS 16 'in the wild' that would allow you to make the CWID changes & hangtime that you're asking about.