Radioguy7268

The wording I have seen from the FCC doesn't prohibit business use - but it does say something about "Coordinating Licensee's activities". I've seen plenty of Family Farms using GMRS. A Mall that's using a non-identified Repeater on GMRS frequencies is probably NOT a "grandfathered" activity. From what I recall, those entities that received GMRS authorizations back in the day were things like AAA traffic assistance, REACT groups, and Town Watch organizations. Have you done a search of the FCC's website in your local area for that Frequency? If they're legit, you should find a license on the frequency, even if it's held in some other entity's name (Like an operating company for the Mall). In your particular scenario, I'd be tempted to put one of my repeaters on the 462.xxx output frequency and match their PL/DPL. Then I'd start ID'ing with Morse Code every 15 minutes (with PL!) If they're a legit user, you should get a phone call pretty quickly. If they're not legit, they'll go away soon enough. Hopefully they would get a real License on an IG business band frequency.... but there's probably a reason they didn't do that to start with.

The R1225 UHF repeater came in 2 versions. A Low Power model starting with model # M04GRC***** and a Higher power version model starting with M44GRC***** The lower power version will do 1-10 watts - and do it with nearly a 100% duty cycle. Those units have a smaller heat sink on the back of the transceiver, and rarely had problems with burning up, even with heavy use. Many people used those for on-site use with Portable radios, or for driving a power amplifier to achieve higher wattage power outputs with a higher degree of reliability in high duty cycle applications. The high power versions were rated as being 50% duty cycle at 40 watts, and 100% duty cycle at "mid power" settings of 20-25 watts. Those units commonly burned up - especially if someone tried to run them at 40 watts with anything approaching 5 minute conversation times. The higher power models did have a much more substantial heat sink on them, but you still needed to have good airflow if you wanted to run them at even 25 watts for any period of time. I've seen those units burned up even when run at the lower power levels that were advertised as 100%. Motorola should never have sold the higher power version at any level above 25 watts, and they should have said even then that it was a 50% duty cycle IMHO. I would be VERY careful buying a GR1225 off Ebay if I didn't know the seller or the source of the unit. Make sure it works and transmits with advertised power! Make sure the seller accepts a return if it doesn't. The amplifiers can be repaired, but its done wrong as often as it's done right. The cost to repair a burned up unit at the local radio shop would probably equal or exceed what you paid for it.

Some operators would choose to ID every 15 minutes with no breaks as a way to advertise their "presence" on a channel. If you were trying to locate a repeater to use in your area, picking the ID off of the one you hear the best could serve as a way to put you in touch with the owner of the machine. Not everyone posts their info on MyGMRS. Also, if you're going to invest the time and money to put up a genuine high elevation repeater with good coverage area, having a constant ID would serve as a way to Mark your Territory, letting others know that you're already on that channel. Also, having a unit throwing out an ID constantly can serve a "heartbeat function", letting the owner know that there's power to the site and the transmitter is still able to transmit. Those are just 3 of the reasons I can think of, there's probably more.

In fairness, I'm going to be base-lining the units to meet advertised factory specs. I don't want these to be some type of "Super" units that have been tweaked beyond what the typical buyer would find in a used unit online. They'll be tested to perform to spec, and guaranteed to be fine examples of what's available out there in the Part 90 world of used radios. They will all have up to date Firmware, and I'll be using standard CPS software with 25 kHz Wideband entitlements. I hope to finish things up this weekend, and I'll ship them out to mbrun early next week.

Any good discussion on radio grounding and surge protection should point you to the Motorola R56 guide as required reading. I believe the latest version is over 700 pages. Copies of previous versions are available online with a quick Google search.

Where did you read that DMR was allowed on MURS? I've been of the understanding that MURS is analog only. Is this part of the Part 95 "short digital bursts" for GPS location data like what was allowed in GMRS ? I could be wrong - so feel free to enlighten me. I never sit up at night reading the FCC rules anymore. I've been under the impression that MURS still allowed some analog Wideband on just 2 channels - but not DMR. Also - is the Anytone D-578UV a Part 95 Certified radio? Is it Part 90?

I'd be willing to send you 2 of my Vertex VX-261 radios to try out. They're available online used all the time for under $100 (often under $50). I've always considered them to be a much better value than the Baofeng's. I'd be curious how they'd hold up side by side against the Wouxun. PM me with your details. There's a good chance I'd have another set of higher end units to try out if you're willing to do some extra testing.

How is the radio grounded? I'm thinking there's some flex in the vehicle as it goes into gear, and you've got a weak ground connection. Sheet metal screws through the carpet doesn't seem to be the typical mount any longer. Plastic consoles and such, combined with a magnetic mount (or similar isolated non-roof mount) antenna can cause those types of problems.

Zetron doesn't want to talk much if you're not a dealer, but I'm pretty sure they're not making the Model 37 Repeaterman anymore. Best outlet I've got for pre-made Zetron cables is MRE1032 on eBay. He will do custom cables if you can provide a pinout. If you want to do your own try taking a look here: http://www.repeater-builder.com/zetron/pdfs/zetron-37-manual.pdf

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.