Radioguy7268

I'll grant you that I haven't actually seen one of the KG-1000G mobiles come across my bench yet. I also haven't seen a technical manual showing the circuitry. I've heard a few claims online that it has a Super Het front end - but color me suspicious. When the receiver is covering nearly all bands from DC to daylight - you can be pretty sure it's not a selective front end.

I don't really care much where a product is made. As has been said here before - CCR has simply become a shorthand for any "Radio on a Chip" design that uses the RDA1846 or a similar chip. Those radios claim to do some spectacular things, and in a way, they do. However, they don't do it very well in the Real world. The one we all live in. One where there are other radio transmitters on nearby channels. I'd much rather start with a radio that has good front end filtering and effective sensitivity combined with selectivity - than to have an FM broadcast receiver, or a flashlight. Especially if I'm building a Repeater. As for buying stuff of Ebay - yes, you do need to be more careful. However, if I bought something off Ebay that wasn't working - I'd send it back & get a refund. Ebay makes that pretty easy. Just because someone calls out a radio for being well marketed garbage doesn't mean they're a Snob, or anti-Asian. It doesn't mean they're stuck in the Stone Age or admiring the glow from vacuum tubes. It just means they've seen this movie before, and they know how it ends. Take my advice, or don't. BuyTwoWayRadios.com is marketing something. I'm giving some free advice.

Given the poor receiver selectivity of most of the CCR import radios -- I'd be really hesitant to use a Wouxun as a Repeater radio. Especially since you could buy two quality used mobile radios and do the same thing - at probably half the cost. Simply put - there's a lot of better options available to anyone who wants to run a repeater.

... and Tone would be referring to the PL (Private Line) Tone - usually expressed in Hertz (Hz).

I would NOT buy a CDM radio off eBay unless I totally trusted the seller - and/or knew exactly what I was getting. The CDM mobiles came in a few different models (Lo Band, VHF/UHF 220 Mhz) - one of which was the "LS" UHF LTR Trunking version - which was later updated into the "LS+". I believe that the LS+ was even capable of operating on Passport Networked LTR Trunking systems. There's been lots of people who have flashed the LS and LS+ models over to conventional firmware - and screwed things up. Other people have done it successfully. Which one are you dealing with? Best site I've found for in-depth CDM reference online has been the Waris page of W9CR - https://wiki.w9cr.net/index.php/Waris You can also get an education by looking over at Repeater-Builder.com or at Batlabs.

I'd be looking at the equipment used also - on both sides, in addition to a full Preventive Maintenance check as suggested above - on both systems. PL tones that are "drifting" (not holding steady to the actual tone frequency) can cause what you're describing. There's alignment that needs to take place between the transmitters and the receivers - ie: a transmitter that isn't steady is going to have trouble with talking into a repeater receiver that is too "tight" and doesn't allow for any leeway to either side of the desired tone. A receiver that is too loose is going to have the trouble you're describing - it's going to open up even when the actual PL is outside the normal "window" of desired operation. If you want to get deep into the Tone PL theory - Repeater-builder has a bunch of good write-ups on PL and DPL/DCS : http://www.repeater-builder.com/tech-info/ctcss/ctcss-overview.html The good news is, most of this was all worked out 40+ years ago, and if you're using quality equipment, it's mostly built-in. Zetron has a pretty good write up of all the details for "tuning" for proper PL decoding in the back of their Model 38 manual - copies of that manual are available online. The only times I ever spent time tuning for PL was when I was using an External Tone Panel to decode user tones.

Kenwood's dealer site has a pretty good set of training videos under "Kenwood University", but if you're not able to access that, I'm not aware of any other training type videos. Even the official training videos are more of a high level overview, rather than drilling into specifics of particular setups. I've always been a Learn by Doing type of person - but it does help me get up to speed quicker when I've got a working template to go off of. Perhaps someone with NXDN experience could share a working codeplug for one of their systems as an example?

I'd agree that trying to set up the software and program a CDM radio can be a daunting task for someone new to radios. Heck, I remember getting a call from a guy with 40+ years radio experience because he couldn't figure out the "Personality assignment to zone" feature Motorola tossed in at the bottom of the CDM programming tree (it's not a bug - it's a FEATURE!). I'm glad you found your way to used-radios.com The stuff they sell is pretty decent at prices comparable to what you might see on Ebay - but as you found out, they'll also do the programming, which can save you some money and some hassles if you really just wanted to buy a radio you can count on right away. Older Kenwood software can have some of the same issues running on newer Operating systems, but in general the Kenwood stuff is easier to acquire and use. If there is a plus, the CDM has some pretty good audio quality - and their reliability is also good. Most of the times I've seen a CDM with problems, it was because somebody was hacking around with the software. You probably won't regret your purchase once you're using the radio and making clear contacts.

In that price range, I'd recommend a used XPR6550 - hands down. You can buy them in good shape and working for less than $100 with charger on everyone's favorite auction sites. A decent new battery (prefer the Motorola OEM Impres batteries that would last 3-4 years) would run you less than $70. Audio quality is excellent, spec's are very good, and they'll do DMR digital - useful if you're a Ham, or just want to scan other stuff. If you don't like to deal with Motorola software - then go for a used EVX or VX portable by Vertex. Look for an EVX-539 for a Digital capable keypad radio - or the VX-459 if you want an analog radio with keypad. Other Vertex models don't have keypads - which aren't really necessary for GMRS and I've snatched up VX-231 or 261's at less than $20 each in good shape. Vertex parts, batteries, and software are cheap and available. Their radios have decent specs and quality, and they're good performers with a low entry price. If you're still not satisfied - look for a Kenwood portable. I'm not a Kenwood expert, and someone else could probably give you some better specific model advice, but in my experience - Kenwood has excellent audio & build quality and they're easy enough to work on. Parts and software are also cheap and available. ANY of those 3 are better choices than a new CCR.

I've got a couple of extra 7550 cables - PM me with your address. Free to a good home. Just pay it forward.

If I'm understanding what you're describing, it probably looks similar to this 3 channel unit: http://www.csgnets.com/wp-content/uploads/2015/03/UHF-CAVITY-TRANSMITTER-COMBINER-3-CHL-125W.jpg Each of those combiners would take up a little less than half of a full sized rack - so if you had two stacked, there's very little space left for much else. I haven't used one of those style combiners, so I can't vouch for their specs. They're supposed to be less loss than a typical close spaced ferrite combiner. Yeah, start up a new thread on your setup. That's impressive for what you started with vs. what you've managed to put in there.

A 4 port combiner technically has 4 ports. How you get 8 'technical inputs' from a 4 port combiner confuses me. Please post a part number, picture or description that explains the 4 port/8 input combiner reference. The only way that makes sense to me is if you're planning on 4 DMR repeaters - which we know isn't legal for GMRS. You're usually going to see much more than a 3dB loss in a 4 frequency combiner system. The lowest loss combiners that I'm aware of are the TX/RX T-pass racks, but their lowest loss ratings are when you're combining frequencies that are spaced more than 1 MHz apart. Combining tight frequency spacings like GMRS repeater transmit pairs onto a single transmit antenna would lead to very high losses - and would likely require something like a "hybrid" combiner - with losses more on the order of 8+ dB per channel. I've seen 4 cavity ferrite/hybrid combiners that required 100 watt repeaters just to get a 10 watt output up the coax leading to the antenna. Those setups were nice if you had a cold mountaintop site to heat up, but played hell on the air conditioning requirements for a cinder block shack in the summer time.

I would NOT recommend doing that on GMRS. While it's technically feasible - "creating" your own new repeater channels by offsetting your transmit center from the existing "main" channel is definitely outside the letter of the law - and would infringe on the repeaters on either side of your new split. I do agree with Gman's point about just putting up a Private repeater on standard LMR channels if that's what you want. I doubt there's that much spectrum congestion in Ohio. Run a UHF FB6 "Private carrier" - and just waive everyone's annual user fees if that's what you feel like doing. I'm not aware of any requirement for a Private Carrier to run as a for profit entity. The FCC has never asked to audit my books to make sure I'm making money. The only downside I see to that would be there's no option for 25 kHz analog wideband, but it opens up a bunch of other options - like Trunking, DMR, encryption, etc. As far as someone charging for use on GMRS - if he's doing it as a non-profit just to "cover the bills" then he'd probably be glad to see you take over with a larger coverage and save him the hassles. If he's actually doing it for profit (and the way you make it sound - I'm confused how he would get so many willing customers paying high enough fees on GMRS to make a profit) - then yeah, he might be upset. But what's his recourse? Complain to the FCC? Tell people NOT to go use the Free system with more coverage area? What's he going to threaten them with?

What's not to like? It's even got a "FUN" button! Seriously - if you want a scanner, it's probably not a bad choice.

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.