Radioguy7268

I'll take a stab at critiquing that Ebay sale (Everybody on the internet is an expert.) First off - the XPR8300 is a 1st generation DMR repeater. It's really 2 XPR mobiles in a box, along with some system specific hardware to keep the two timeslots sync'd up. The XPR8300 was kind of famous for burning up the Transmit side if you ran them at high power - and let the cooling fan run off the built-in thermostatic control. The 'trick' was to run them at lower power, and hack the fan to run continuously. At that point, they would live, but still had limits. In the Digital world, the units were limited by internal memory for some of the higher end DMR functions. They weren't going to play well in a higher end system, but they were suited well enough for single site systems. The XPR8400 was the improved version of that design, and seems to have held up much better than the 8300. Next up - you've got the eBay side of things. $300 + shipping would be a fair enough price - IF you needed DMR, and you knew that the repeater worked. But, it's an auction listing, and you don't know what the final sale price might be (or who you might be bidding against!) Then you look at the seller, and you see someone with a nearly zero feedback rating. That's taking a major chance on the seller. The guy might be OK, or he might be fly by night... you just don't know. The listing shows a nice clean workbench that's apparently new - along with a Bird Wattmeter, so it makes me think the guy has some skills - but also makes me think that he probably found a burned up XPR8300 and swapped the bricks (flipping the burned up transmit radio over to the receive side - then re-flashing the 'good' radio to move over to the transmit side). That can be done successfully - but you need to have some equipment to make sure everything's up to spec once you're done - and I don't see any type of a Service Monitor in the backgrounds of the pictures. If I was searching for a GMRS analog repeater in a box, there's probably better places to spend my money. If I lived near to the seller in Kentucky - I might take a trip over to see that XPR8300 in person and talk to the seller - and see if I could save $50 in shipping. I like the MTR2000 for GMRS. You can grab one of those in the 40 watt "low power" version for $600 or less if you're patient.

The real problem is - they don't realize that for similar prices, they can buy used commercial radios that have 10 times better specs.

I'll agree that plenty of people pick and choose the rules they like & disregard those they don't. I was wondering about your comment regarding the ID requirements (Around here, I always hear people ID'ing in English - even if they're speaking another language during their conversation) - but then I saw that you're in Puerto Rico. I'd guess there's a little bit of a special case there. I'd have serious doubts that the FCC would ever get around to trying to enforce that rule on the "isla del encanto". Add me to the list of those who would like to see the exact rule that prohibits Internet linking. I'm of the understanding that they're doing a bunch of linking down in Puerto Rico ever since Hurricane Maria.

If the radio's codeplug is password protected -- you're going to need to find out what the Password was from the last person who programmed them. I'd start with the buyer - but if he doesn't know it, you're in a tough spot. I would be trying to return them ASAP if the seller claims that "I got them that way". To be clear, I am assuming that you were able to load the Retevis program, and hook up cables to read the radio. If the program itself requires a Passcode to install/open it - you're going to need someone more familiar with their software & any workarounds.

For goodness sake, IF you're going to amplify a hand-held, you should do it with something that isn't putting out spurious birdies on 3 different frequency bands. That would be a service to the GMRS (and surrounding) spectral communities. Amplifiers are broadband noise generators. They're going to amplify whatever you put into them, including spurious signals that your $39 CCR is generating. Cheap amplifiers hooked up to a cheap portable are a recipe for disaster. Even a good amplifier hooked up to a CCR is going to be problematic. As others have mentioned - just use a 25 watt mobile with a decent antenna if you want to put out more power. You will spend less in the end, and have a MUCH better solution.

Hopefully you've already read the thread on: "I just got my GMRS License and now I want my own repeater". Solar and high power repeaters don't play so well together if your budget is less than NASA. If you've got a high elevation site, you can talk to everywhere you can "see" at relatively low power. Higher power margins just help to overcome background noise and decrease fading. I'd tell you that 10 watts going into an actual 6 dB antenna is an ERP of 40 watts - and probably overkill if you're using 4 watt portables to talk back. If you really want to make a repeater work better - a better receiver is worth much more than transmit power. If you really do have the idea of "doing it once, and doing it right" you need to forget about Retevis for a mountaintop site, and you also need to forget about using tupperware. A NEMA style weatherized box can be placed outdoors, and will hold up well against the elements if you pay attention to properly sealing up any holes or bulkhead fittings. I've got outdoor sites that have held up for more than 15 years with a NEMA box on a pole - but I wasn't dealing with 8000+ ft elevations or extreme winds/icing. You can buy a high end used commercial repeater like an MTR2000 for about the same cost as a new Retevis RT97 - and you're getting 10 times the quality. Most reputable sellers will even program it for you - saving you the expense of cables and software.

... and as usual, the topic has been sidetracked, the OP has disappeared never to be seen again, and we're left arguing minutia of the meaning of poorly written rules that aren't enforced anyway. <sigh>.

GMRS would probably do what you want - and might be a really good fit, especially if you want to use hand held portables. GMRS runs on UHF frequencies - and you would not re-use your old VHF antenna(s) for GMRS. If you're more interested in just having mounted radios in your vehicles, then VHF might still be a good option. Pricing for VHF vs UHF/GMRS radios would be comparable. The cost of a Repeater for UHF/GMRS would probably double the overall cost of your system. I think that you should probably try to get some local help - someone who knows radios and could take a look at what you've got, and ask the right questions about what you want to accomplish, and give you some ideas of what might fit your budget. Someone else will probably bring it up - but GMRS licenses run "per family" - ie: One license covers one set of relatives. If it's a family farm, it's pretty simple. If you've got unrelated employees, then potentially you would need to license each of them individually. A VHF or UHF commercial/business License would not have those limitations, but it is more expensive to set up a License for that type of operation with the FCC. I've got a nephew with a family farm out in Indiana. He's running GMRS with a repeater up in the barn, and he gets a good 3-5 miles with portables - even further with his mobiles.

Without diving into the ins & outs of tuning a duplexer (I've got my doubts on a 20 watt loss being blamed on poor design) - I'll just go along with your split antenna system and say this: Good practice theory says that for UHF you should use at LEAST 10 feet of vertical separation between the Transmit and receive antennas. Horizontal separation would require at least 1000 feet for antennas on the same plane, which really isn't practical. The higher your transmit power level (or the worse your receiver's selectivity) the more vertical separation you'll need. I'd still put some type of bandpass cavity on the receive side to improve selectivity & filter out unwanted noise. Somewhere out on the internet there's a few charts showing the recommended vertical spacing for different frequencies. (As you go higher in MHz, the need for physical separation decreases as a function of wavelength.)

If we are talking about the "low profile" VHF antennas that screw on to a standard NMO mount - they're about the size of an Oil Filter. They might not be tall, but they're still presenting quite a wide profile. The Pulse/Larsen ones I'm familiar with also required on the vehicle tuning to achieve anything close to a 1:1 match, and you usually got frustrated around 1.5 and said it was close enough. The bandwidth when tuned wasn't more than 1 or 2 MHz above/below the tuned center freq. Hardly "wideband". I would probably recommend just using something like a standard 1/4 wave whip tuned to the frequency you're most interested in transmitting on - and then just live with the performance on the receive side. It will likely be good enough for 90% of what you're interested in listening to. If you need to work specific frequency bands outside the tune of the antenna, just carry a few different lengths to screw on in under 30 seconds. If you're worried about what the antenna might hit, consider something like the Stico super flexible mast. If you really want low profile in VHF - then use a Transit style antenna like the Sinclair Excalibur - but get your wallet out. Those run @ $250 & still require tuning - with a narrow bandwidth.

Radio Mobile is one of the best available online coverage calculators available - especially when you consider that it's Free to use (for amateurs). My only comments would be that you need to bump up the "Required Reliability" % to something North of 95% to better reflect actual coverage. Also, realize that it's mapping Talk Out coverage for the most part - not taking into account the difference between a mobile mounted radio or a portable (other than antenna gain & height). I usually set antenna gain at Zero for a portable, with a 1 meter antenna height. I find that gives me a more accurate representation of Real World talk back conditions with a decent portable.

Can you cite any instance where the FCC has actually fined anyone ANY dollar amount for using a Part 90 radio for GMRS? In fact, can you even locate an enforcement action where the FCC has admonished a user for using a Part 90 radio in GMRS? Just saying, because if you're going to wave around a $10,000 fine - you actually should show that the weapon has been used. At least once.

I believe that Montgomery County has 462.725 on the air as an "Emergency Service" repeater using the 141.3 travel tone. I'd assume that they monitor that channel - and if it was a constant carrier that was opening up all radios on Channel 22, the county themselves would be aware of it. I am in Central Montco near 476, and I just went and put both 467.725 and 462.725 into a radio attached to my roof mounted antenna to listen & see what I could hear, and I'm not receiving anything constant on either 462.725 or 467.725 on CSQ. I do get some sporadic and weak simplex analog voice on 462.725 that sounds like its related to construction work. I'd ask what type of radio you're hearing this on - and what's your situation? (in car portable, mobile with roof mounted antenna, base radio, etc.) The fact that you refer to it as "Channel 22" makes me think you might be suffering from front end overload on a cheap portable. There's a ton of radio traffic on the Route 476 widening project right now.

The model you want will start with P94ZRC90 The P1225 came as either a 2 channel or 16 channel model (plus a 16ch keypad version with display). Software can be a stumbling block if you're not friendly with someone who has a copy. It used to be available for anyone who had a MOL (Motorola Online) subscription. I've got a boatload of the P1225's. PM me and I'll hook you up.

How long is the run? How flexible do you need the cable to be? (do you have tight spaces/tight turns?) What's your budget? Generally - what's termed "hard line" - Coax with a solid jacket (often called Heliax) - is going to have the best performance specs, the highest cost, and be more rigid. Braided coax (like LMR400/600) is more flexible, a little less expensive, and brings it's own issues.

I've sold at least 3 phone patch enabled repeaters within the past 4 years, and I'm 30 minutes away from Route 95 in the busy Northeast Metro corridor. In-building coverage is usually the issue, as well as the cost to equip 5-10 people with 'casual' but important phone service that might require less than 4 or 5 calls in a month. Compare the ongoing cost of 10 phones at a bare-bones $35 per month + a BDA system to provide in-building coverage, and suddenly 10-15k for a simple phone patch repeater makes all the sense in the world.

WRAK968 - send me a PM if you're interested in a used (but good) housing for an XPR7550e.

Motorola does an ALT process (Accelerated Life Test) where they automate certain functions like turning the radio on & off repeated times quite rapidly, changing channels, pressing the PTT button, along with repeated drops from a 4ft height onto a hard surface. This is supposed to simulate 5 years of typical use within a short testing time frame. https://www.youtube.com/watch?v=Y_ScXS4mrvY This isn't exclusive to Motorola - other manufacturers have similar testing procedures. Any radio with Mil-Spec ratings probably went through similar testing. I am not disputing your experience (and a replacement XPR housing from Motorola is quite expensive!), but I am saying that the radio is designed to survive a typical drop - and I've got stories of units that dropped 30 ft. down an elevator shaft onto concrete and survived. I even have one story about an old SP10 plastic chassis radio that went through an asphalt plant, emerged looking like a bent black banana, but still would transmit & receive! I've also seen some units that appeared to be almost brand new on the outside, but were totally crushed inside - and the customer swore they didn't run over it with a dump truck.

Yes, the XPR7550e has some great performance. There's also a plethora of programmable audio options, and you can purchase (or not) a bunch of minor EID's that will enable things like Face-down mute, Enhanced Noise Cancellation (SINC+) Receive Audio Leveling, and Bluetooth. One point about your testing - be real careful just swapping around antennas just because they fit the connector. I think if you do a back to back test with the standard EVX ATU-16D antenna, you'll find an improvement over the PMAE4048 Motorola antenna. I think if you measure the length, you'll see that the Vertex "Standard" (Pun intended) antenna is a bit shorter. I've also noticed that the aftermarket Vertex antennas available by the dozen on Ebay seem to have issues with breaking apart internally due to over-torquing.

No problems here - your answer did include some helpful information. It's just that anyone reading through the responses would wonder why a GMRS forum wasn't leading with a GMRS solution to a GMRS question! I'd also say that 4-5 watts UHF GMRS portables would be the equal or better compared to 2 watts MURS in most real world scenarios requiring signal penetration in and out of buildings and vehicles. Plus, if you start with some decent UHF GMRS portables, you've got the option to program them to a repeater. There's simply no option for MURS bubble pack radios to work on a VHF repeater.

Guy comes to myGMRS.com - asks about a GMRS solution, and the first 2 answers he gets suggest MURS & CB? C'mon folks. This is why people get frustrated with asking for advice online. YES! GMRS is a good solution for what you're looking to do. You might be able to get 1 mile or so out of UHF handheld portables - but a simple GMRS repeater at roof level will probably get you between 2 and 5 miles without even trying. Now - you're going to need to do some reading and educate yourself to a certain level if you want to do this on your own. Otherwise, open up your wallet & call the local two-way radio shop, and purchase their parts & experience. https://forums.mygmrs.com/topic/1402-you-just-got-your-gmrs-license-now-you-want-your-own-repeater/

Part 90 software only difficult to obtain if you're trying to get it both cheap AND legal. If you don't mind spending the money, Kenwood is easy to get from any Dealer, and Motorola isn't always cheap or easy, but if you can spend the time to set up an MOL account (Motorola On Line) it's easy enough to obtain. Otherwise, Ebay has about 100 listings on any given day for copied software burned onto discs - and there are sites out there on the interwebs that offer free downloads - although it's not always current/up to date versions & it's nearly guaranteed to be stolen/unlicensed.

The only Part 90 radios that I'm aware of that used Sideband was some Aerotron stuff in the '80's that worked on certain odd narrowband splinter frequencies in the VHF band. SEA (Datamarine) took that same tact and used ACSB for the 220 MHz band in the late 90's. I'm not aware of any manufacturer who tried any AM Sideband for UHF frequencies with Part 90 equipment. I played around a little with the SEA stuff and thought it was decent for what it was. They used a pilot tone in the middle of each narrow channel to try to keep everything centered on frequency. I remember that certain voices (higher pitched young women) would drop out certain sounds - I specifically remember that "Six" and "Seven" would cause problems. Put a middle aged male with a raspy voice on the mic, and it came through loud and clear with every test count. Ran our techs around in circles until we figured out what was going on - the higher pitched voices were running right in the middle of the notch for the pilot tone!

Without trying to go too far off track - what I've got (as an example for the OP) is the RMN5127A mic. It's got the 4 way navigation key - but no display. Those run @ $100+ (new) as an add-on option to the XPR mobile. You would probably also need an optional Mic cord extension to remote mount the radio under a seat & not need to stretch the std. mic cord, or just have a convenient place to plug/unplug the mic cord if you want a "hideaway" option. What I've got looks like the attached photo: There's another member on here - Cory, who has the HHC mic option for the XPR5550e.

The Motorola XPR5550 & 5550"e" version both have a Handheld mic option with the capability to switch channels from the mic and use DTMF for control. You can remote the transceiver and run an extension cable for the mic. It's also got voice announcement, so you don't need to look at the large (color) display for 95% of normal functions. It's not a Part 95 radio though, it's Part 90 commercial, and will also work on DMR. A brand new unit will run you 3 to 4 times what a Midland would cost. Used units are more reasonable, especially for the older Non-e XPR550. In fact, I've got one of the XPR5550 models with the advanced mic option that I previously used on GMRS. Color display, voice announcement, and only driven on Sundays. Guaranteed working. PM me if interested.