Radioguy7268

Microwaves were invented during Roman times - Emperor Nero cut off some dude's fingers & left him with only his thumbs. That same guy (Digitalis Minimus) went on to invent the UHF PL-259 connector, for hams who were 'all thumbs'. True story.

Double check your programming on both sides (repeater and mobile/portables). I'd think that it's more likely a fat-fingered typo than a problem with the antenna & line. It's either that, or you're describing a de-sense issue in a unique way... The suggestion of testing in simplex with another radio hooked up in place of the repeater is a real good test for basic troubleshooting. If a portable works just fine in simplex mode, then there's likely a problem with the repeater or duplexer. If you experience the same problem when testing with a portable - then you know you're looking at a coax/antenna issue.

Assuming you don't need to hire a climbing crew to install that new antenna & hardline, then yes, the price of a 2nd antenna & line is probably much less than a tuned transmit combiner & receive multicoupler system. Having two repeaters close in proximity and close in frequency can lead to some issues if you're just using compact (inexpensive flat pack notch) duplexers that have very little protection from adjacent signals. Meaning that if you try to use the 462 GMRS repeater at the same time as the 463 Part 90 machine, you could create some of your own interference. If you're not keying both machines at the same time, then you're probably good to go. If you want to have both repeaters keyed up at the same time, you'll either need to use better quality filtering (think high end $1500+ bandpass/band reject cavity duplexer per machine) or a quality transmitter combiner system. Not many 'hobby' type systems can cost justify a combiner.

You set Pin8 to PL/DPL - CSQ detect on the Repeater's RX (receiver) radio. This is how you make sure that only intended transmissions (from your group's properly programmed mobile/portable units) will be received on your repeater's 467.xxx frequency. The transmit radio is then being told to key up upon that receive decode action. There is no need for your Transmit radio to detect incoming PL/DPL. It's function is to transmit - but you should still generate a PL tone or DPL code for the Transmit output. Some people try to program the receive and transmit radios the same way - with the idea that they'll be able to swap them around more quickly once the transmit radio burns up. IMHO that's the wrong move. My take would be to program each radio for it's intended use, and set it up properly the first time. You can always save & store the codeplugs for later use to reprogram or re-purpose a unit via the Clone function. If you take the time to set things up properly - AND TURN DOWN THE TRANSMIT POWER - the repeater will live longer, users will be happier, and you will have more time to go about improving the system instead of thrashing around trying to figure out what broke this time. Repeater-builder.com is an excellent resource for anyone trying to build, setup, or program their own repeater.

Well, First you should make sure that is what you want to do. From what you've said, it's possible that you're looking for a multi-tone panel to separate user groups on your repeater by PL tone. Adding an external tone panel to your repeater is not quite at the level of simple, but it has been done, and there are panels (and cables) designed to work with the Vertex EVX-R70 repeaters (and it's cousin the Motorola XPR8400). There's probably some online instructions out there on Repeater-Builder or similar sites. I'd peg it as a project for intermediate with skills to advanced/experienced. The inexpensive way for someone with experience would be to buy a good used tone panel (I've seen used Trident Raider panels go for less than $50 with free shipping on eBay) and find some online pinouts for crafting your own cable. You would also need some equipment to set deviation levels and repeat audio, and you would need to reprogram the repeater to function as a base with an external control panel. Without knowing your skill set, patience, and equipment - it's kind of hard to give a recommendation. Trading out your repeater for another unit that already has a Multi-tone function built in (Kenwood TKR) might be an option.

You can certainly use an external controller & set it up like a community repeater with multiple PL or Tone groups. If that's what you want, there are other Repeater options out there with that feature built in, but a $75 or $100 used external controller will do the job. I doubt you would want to manually switch tone groups.

There are ways to do channel steering through the rear accessory connector - and programming the GPIO pins, but I don't think I've ever seen anyone doing it on the lower end repeaters. As you discovered, there is no real reason to do anything more than 1 channel for most of us. Other than that, it's just legacy from the original mobile radios that are inside the box - and someone decided that advertising a 16 channel repeater was more impressive than just a single channel.

I remember hearing an old timer story about the one time they got fined from the FCC - because they had a Part 22 transmitter that was BELOW the wattage specified on the license. The FCC had warned them, and they didn't take it seriously because... well, nobody ever heard of a fine for being below your allowed power. That story came about because we were brainstorming around at a dinner meeting during the early days of narrowbanding and refarming, and some of us saw the same opportunity for more available talkpaths in Part 22 if you did some creative channel splitting and re-use of offset frequencies. The old timer warned us that in Part 22, things didn't need to make sense but you did need to follow the letter of the law. Again, that was 20+ years ago and a different era with the FCC and enforcement actions.

During that FCC Auction 20+ years ago, I attended an FCC Seminar down in DC & got to sit in with a bunch of people talking with FCC staff attorneys regarding the Auction process. One of the things we learned was that the FCC was only allowed to auction spectrum if there was more than one competing application for the allocation. That was the reason the attorneys always suggested that people checked the "all" button on their application, as they wanted to make sure that every market had a potential competing application. You did not need to bid on all the markets you expressed interest in, but without a competing application, the auction process could not legally proceed. Not sure if it still works that way, or if the FCC convinced the legislature to amend the auction rules. You would think that the concept should be to put the spectrum to use - rather than to just maximize Federal revenue. Google 1997 PCS auction defaults if you want to read up on some FCC comedy.

More than 20 years ago, I got involved in an FCC Auction & made an honest effort to get some VHF channels in my economic area. The economic area I was interested in went for over $2.5 million for what amounted to about 8 possible channel pairs. Part 22 channels from back in the IMTS days were gold. Most of them around my area are being used for linked DMR wide area systems. There's even still some wide area Paging on the old VHF Part 22 channels. Not sure how much availability there would be if the FCC protected incumbent operations.

Yeah, but the desense issue is huge with a compact duplexer. Even when properly tuned, if you over-power the transmit side, you are still introducing a weak but competing signal on the receive side that WILL reduce the talk-back range of your portables. Worst of all, your own equipment is what's producing the interference, and you probably paid more money to get all that interference!

Or, spend $800 to $1000 and get a purpose built repeater with a decent receiver front end that won't desense, and cooling fans to boot. Public Service announcement: your "50 watts" won't perform any better than a properly configured 10 watt repeater when you are talking back in with 5 watt portables. Especially if you're talking through a cheap compact duplexer that's probably rated at 65 or 70 dB isolation (and that's when it's properly tuned).

I've still got my Navajo codebook from Windtalkers.

In a SHTF / Post apocalyptic scenario the bad guys you are trying to protect your family from are going to be keenly interested to know who is trying to move valuable items. Value can be subjective, but a couple of yahoos getting on their GMRS radios and talking in code is more likely to draw attention than to deflect it. I don't think I ever said that trying to protect your family was a bad intention, but the people with truly bad intentions are not going to care how good your GMRS code ettiquete is. You have fun though - and by all means, keep us informed of your progress and the best code words to use. Things have been dead over here on mygrms forums lately.

If you think using codes will "protect" you - then have at it. If you're really looking at things from a SHTF perspective, analog radios are problematic to begin with, especially if you're in a single frequency/channelized domain. If I have bad intentions, I really don't need to know specifically what you're talking about, I can pretty much determine how many different people I hear talking, and I can easily triangulate your signal to figure out where you are.

Is it possible that you are misreading the cable, and it's really "RG8/U 95 foam" ??

Sounds like it's some type of oddball 95 ohm coax. What's the application? I sure wouldn't use it for any GMRS applications (which almost always requires 50 ohm cable). Could you even source proper connectors for it? Old coax is more likely to be the cause of problems than the solution, at least in my experience.

Those compact "flat pack" duplexers are not really designed for 50 watt applications. I also didn't quite catch who was tuning those duplexers. I've seen some sold on Ebay that are horribly tuned, and others that have been tuned quite well. I would not blindly trust that a CCD (CheapChineseDuplexer?) is actually tuned to the frequencies requested when it was ordered. I would also tell you that the amount of isolation between transmit and receive doesn't really allow you to run 50 watts through one of those flat packs (even when it's properly tuned) without some level of desense. In short - a portion of your transmit signal is going to leak over to the receive side and cause you interference - AKA desense, reducing the performance of your own repeater. And finally - the point I always get back to. Every rookie out there wants to get a full 50 watts, because more power is always more better - right? Well, think about what you're doing. You may get a full 50 watts heading into your duplexer, and if you're lucky, 30 or 35 watts heading out of the duplexer & up to your high gain antenna. But, what are you talking to? Hand held portables at 4 or 5 watts? How far can they talk back in? You just reduced their talk-back performance by leaking some transmit power over to the receive side, probably killing 2 or 3 dB of receiver sensitivity. Now that 4 watt portable is effectively talking in with the same effectiveness as a 2 watt portable, because you're reducing the receive side performance all so you can crank 50 watts into the duplexer. Back the power down to 20 watts, still have ERP to spare, and suddenly your 4 watt portable gets back into the system a bunch better, repeater coverage is balanced between transmit and receive, and as an added bonus, parts live longer due to reduced power. Turn down the power. Improve your system performance.

QFT! Talk with a frequency Coordinator, tell them that you want to put up your own Private Carrier system for "Part 90 eligibles" and license your DMR system as FB6 repeaters. Yes, it will cost you more than $35 up front, but now you have the keys to your DMR kingdom, and you can DMR to your heart's content, because every user on your FB6/M06 system now runs under your fancy Private Carrier license. You can (but don't have to) even collect user fees for the use of your system.

Lscott is correct. The handhelds will only transmit half the time - saving battery life on a portable. However, on the repeater side, both time slots are keyed up - even if only one time slot is actually active.

What are you using to measure the power output? Do you know it's an accurate measurement? Do you have a way to measure frequency stability and frequency center if you start changing power levels? What do you wish to accomplish by raising the power, other than to reach the "maximum allowed"? Raising the power on a smaller repeater generally increases the heat being generated, and reduces the duty cycle of the repeater. Many smaller repeaters were advertised as being 50% or even 100% duty cycle at high power, but in reality they don't last when you run them at full power for more than a few minutes at a time. I won't get started on the overkill concept of using a 50 watt repeater to talk to 5 watt portables. Sometimes less is more. I'd rather have 5 watts ERP at 100 ft. above average terrain than 50 watts at 10 ft. Not exactly the answer you were asking for, but hopefully something to think about.

The "best" is one that works well & fits your budget. Are you looking to work simplex to local portables? Mobiles? Or, do you just want to communicate through distant (or local) repeater(s)? If it's through a repeater, do you want to work multiple repeaters in different compass directions? Or, just one specific repeater? How far away are the repeaters you want to work? Any issues of terrain? 75 miles in Kansas is a probably a different solution than 25 miles in the foothills of Colorado. The answers to those questions would likely change the suggestions you are going to get, and you might want to put up a budget range or limit to define the dollars you'd intend to spend. I've seen people work a repeater with a paperclip for an antenna. I've also seen guys working earth-moon-earth contests. Those are probably the 2 extremes you could fall between.

I'm close enough to know where (and what!) the Qmart is, and trust me, they are not the only local users on 151.625. I've got a license for that frequency & use it in my VHF rental fleet. My biggest problem on that channel is a bunch of paving contractors who use it as an unlicensed "chat channel" while they're driving between jobs. Judging by what I've heard & how far apart they've been, they're using at least 25 to 40 watt mobile radios on what's supposed to be a low power channel. Not quite sure why you would willingly admit to operating unlicensed on a freq, but if you're looking for a blessing I doubt you're going to find it. However, in reality you are not the first and probably won't be the last to violate the rules in VHF.

To be clear, Motorola XPR radios do not have a "promiscuous" mode to listen in to DMR timeslot activity without regard to color code or timeslot. You can listen in analog mode, and then when you press monitor, you hear all activity on the frequency - but listening to encoded DMR digital in analog carrier mode is akin to listening to a buzzsaw. It is not pleasant, and it's not going to give you decoded voice on an XPR.

Motorola P/N is: HVN9025 Professional Radio CPS which runs under Windows 95, 98, XP, 7 - not so sure on Win10. Originally 32 bit, but the later versions would do 64 bit. R06.12.05 (released @ December 2011) is the one to look for as it is the last one that allows wide or narrow selection on a per-channel basis (it also fixed a number of problems including the 64 bit Windows USB problems, and it can be found "out there". Revision R06.12.09 was the very last one, however it is narrowband only unless you have the wideband entitlement key. There's also a ton of firmware flashes available (and probably needed for really old first generation units). There's also lots to know if you picked up an eBay refugee that was flashed/converted from an early LS trunking model. The go to bookmark for anything Waris (Pro Series mobile CDM & HT750/1250) is: W9CR.net