Radioguy7268

The Nextel 3rd generation (last generation?) phones had a built in FHSS 900 MHz "off network" radio they called Direct Talk. It is NOT compatible with the DTR/DLR series of Motorola radios, even though it's the same technology. Not sure what in the protocol was different, but I'd imagine it's beyond a simple secret hopset number, or else that info would have leaked out to the public by now. There were a few Nextel phones like the i375s which had an external antenna and were ruggedized. Those seemed to be the units with better range on 900 MHz Direct Talk, but I never did a side by side range test with DTR series vs. the Nextel models.

If it is Fire/EMS voice paging (with tones) - then I would be betting that some nearby Volunteer has put up a budget cross-band repeater to send out their county dispatch/tones on an FRS channel. Do you ever hear voice replies on that same channel? Or, does it seem to all be one-way traffic?

Wow - what tangled answers to a simple question. YES! You can use the EVX-5400 for GMRS! It's a nice little radio. The software does not require a wideband entitlement key like Motorola CPS. You just use the Export or "international" version of the Vertex software. If the radio was previously written with the Narrowband only software, you will need to "unlock" the radio with a special Vertex software module called the "Wideband Recovery Tool" version 1.03 If you're trying to recover newer Vertex radios like the EVX series - you're going to need Version 1.03 of the Wideband Recovery Tool. That isn't easy to find online, and you also pretty much need to invest in the FIF-12 programming box/cable setup from Vertex to make that work with newer radios. The FIF-12 runs about $150 to $200 new. I could unlock it for you for about $25 if it's a one time service. Any other Vertex or local LMR radio dealer could probably perform the service for you also at a similar price. There are also 2 different versions of the EVX-5400 radios. Older models had a 8 character display, the newer versions had a 16 character display. The CE-151 export software should be used with the newer (and more common) 16 character displays for Wideband operation.

Have you ever used that same software to read another Kenwood radio? Has the programming cable ever been used to read/write? Not sure why you can't type in the box, but beyond the "where did you get the software?" question - you've got a radio that you can't read or write to without a password. I wouldn't throw the seller under the bus right away, but if the radio was sold on Ebay as "used" - and it's got a password that prevents the radio from being programmed, then it's up to the seller to provide a password and fix the problem or refund your money. If it was sold under "Parts, not working" then it's your problem.

If you think it is illegal, then don't do it. If you are saying that since All-Star is based on *asterisk (which is an IP based PBX) it fails because it's using telephony to connect repeaters - then please tell us how many people have been cited by the FCC for using "ilegal" All-Star. I think you will find the number of citations is Zero or less. By the way, nice first post.

The best way to know your cable loss is to measure it. Not always practical when you're stringing 150 ft or more of hardline directly from the spool onto a tower, but for most of the GMRS mortals, it's in a coil with terminations installed prior to us heaving it up onto a pole/tower/rooftop. If you know the input power, and can measure the output at the other end before it is hoisted and connected to the antenna, then you can calculate/know your own losses easily enough. I say that because while the manufacturers do tend to post numbers grounded in reality, the various distributors can get a little creative when it comes to their claims. Rounding up, rounding down, convenient lapses in stated lengths (oops, it was 1.5 dB per 50 ft, not 100 ft.) can all make a difference. I've seen some knockoff brand RG400 jumper cable assemblies that had nearly 3 dB of loss in a 5 ft. jumper. It should have been less than 1 dB even including the connectors.

You are correct about the outer pins - they can be pretty much ignored, and the center 16 pins will follow the standard Moto conventions of Radius mobiles. Be aware that the CDM radios will not fit in the stock GR300 housing - the control heads are too big. I've seen people just screw in a mobile mount at the top of the GR300 housing for a cludged look. Also, you really should wire in ignition sense for the CDM mobiles - as they will not automatically restart with loss/restoration of power otherwise. Not a big deal if the repeater is on your desk, but a PITA if the repeater is at a remote tower site. One final consideration for the GM300's - consider finding yourself an old-timer "Elmer" who might already have all the cables/software/knowledge for programming the GR300. Even if you pay him $50 for the trouble or buy him lunch, it's still cheaper than buying a set of used CDM's. Most commercial shops won't touch a 25+ year old repeater for anything other than a trade-in, but the guys who work there probably have the tools and knowledge to do the job if you get on their good side.

CDM's can work - but there's a learning curve with the CDM models. You also need to be real cautious with buying those off Ebay - as there are a ton of CDM radios that have been hacked and cracked. Things like LS+ trunking models that have been flashed over to conventional.... or LS models that only do 16 channels in conventional mode, and can't do MDC. Personally - I'd tinker around with DOSBox for a GM300. The trick that worked for me was setting the "CPU Emulation" to act like a 386. The rest seemed pretty much standard. I have been able to program anything from Radius M300, M120's, SM50's or GM300's.

Cane wireless makes an FHSS repeater setup for DTR radios - http://www.canewirelesspro.com/drx-repeater.html I've never sold one or played around with one, but looks like about a $3000 solution. Need to buy two of their boxes, and separate them with at least a 20 ft length of ethernet cable connecting the two boxes. It appears to be bidirectional to me. One DRX radio receives a particular talkgroup/code - then the 2nd DRX radio re-transmits on a different group. It appears that you would need to have a portable DTR that's set up to scan talkgroups in order to talk back & forth.

I'd also be checking your antenna feedline for continuity. What you described with the ability to transmit, but not receive, could potentially be caused if you have a VERY slight gap between the coax and the connector - effectively creating your own iso-tee. That's why people ring out their connectors when they're done installing them. With your adapters on each end, that possibility becomes a bit more likely.

How did the other user have their radio set up to respond to you? Normal function on a repeater channel is that the portable would listen on 462.xxx, but transmit on 467.xxx If you go to Simplex, your portable is now transmitting and receiving on 462.xxx Unless the other user switched their radio to simplex also - they would still be transmitting on 467.xxx and of course your portable that's listening on 462.xxx would not hear them. As Sshannon mentioned above - there aren't many scenarios where an antenna line would be passing transmit, but blocking receive. I'd put money on the distant user still transmitting on the high side of the split at 467.xxx

You can try this one: 135K4414K073AWGG

There are companies that aggressively search for "open" areas lacking coverage that also have the ability to have a tower placed there. Those companies are responsible for 90%+ of all new tower site builds. They have lawyers at their disposal, zoning specialists, and years of experience building out sites. They also have relationships with wireless carriers, and know that they're likely going to have 1 or more carriers as tenants on the site before the first shovel hits the ground. That's the kind of business plan you should have before you go spending hundreds of thousands (or more) to put up a tower.

I would be curious to know what component of a notch duplexer failed. Unless something cracked or corroded, there's just not much to go wrong inside a tuned cavity.

It's nearly impossible to troubleshoot a system you've never seen from a thousand miles away, but please explain what you did to "tune the repeater closer to the correct freq." ?? There's not much tuning that I'm aware of with a Bridgecom repeater. Were you trying to bring the repeater closer to frequency center on transmit? Just how far had it drifted?? If the setup worked fine (repeater + duplexer) with one antenna system, and then you changed out to another antenna system - it would certainly seem that your new antenna system is suspect. However, I'm curious why you would have needed to "tune the repeater closer to the correct freq." if your range testing with the old antenna system was producing stellar results. What connectors are you using on the LMR400 cable? Was that cable new or used? How hard would it be to swap out the cable? What condition are the duplexer jumper cables in? Heliax is "better" than LMR400 - but for a 35-40 ft run, it should be marginal - especially when new. That Harvest antenna probably has an SO-239 UHF connector, and the DB404 would have had a Type N. Type N is "better" - but again it's not a night & day difference maker. What connections are on your duplexer? Do you have a surge protector or lightning arrestor in the mix? For all the internet stories about duplexers going bad just sitting there, I haven't really ever seen it in the real world. Unless an elephant stepped on it, Zeus hit it with a lightning bolt, or Mike's Magic Golden screwdriver tried to field tune it, then it just kept on working. What I have seen is cheap cables with tin plated connectors deteriorating within a few years and causing all kinds of headaches that get attributed to a bad duplexer.

The most simple way to troubleshoot a repeater is to start with the basics. If you can, follow OffroaderX's suggestion and set up a simplex mobile radio (or temporarily reprogram the repeater as a simplex base - disable the repeat function). Connect the "base" radio directly to the antenna - forget about the duplexer for now. Get a helper to take a radio out to the current 5 mile edge of the system range. Test the transmit function to a distant mobile. You should get the same range (assuming power level is the same as the repeater). If your range increases - need to look at the duplexer and cabling. Now test receive function from that distant mobile. You should be able to receive from a similar distance as you could transmit to. If your receive range improves from what you saw with the repeater - you need to take a look at the duplexer and cabling. I have seen more bad cables than I've seen bad duplexers. Your story about the system working well with the other previous antenna makes me wonder if you were using the same duplexer and cables for that setup. Have you measured VSWR for the antenna system? Do you have the ability to sweep the antenna? That Harvest antenna is tunable - was it set for GMRS when you ordered it? What frequency was it supposed to be set to? Don't just guess at what's wrong. Measure & test so that you know what is working and what seems to introduce trouble when you add it to the mix.

Look for a used Vertex, Kenwood, or Motorola commercial repeater. You could get something like an MTR2000 that's rated for 100% duty cycle at 100 watts (it will do 50 like a breeze) - and still spend less than trying to get 2 Wouxun mobiles strapped together. Most sellers will program and set up the repeater, and give it a warranty as well.

I think you might have meant to say "relegated" to the dustbin of history, but over regulation will get you to the same place

15 to 20 watts. Don't sweat, it will still be 3x better than a portable.

Yes, a genuine kit would include the cables with the correct orientation tabs. But, the really cheap $10 "repeater maker" cable kits sold on Ebay have no orientation tabs, and can be plugged in either way. I have also seen people totally jam in the correct cables upside down, because they were convinced that the tab orientation was incorrect - since it didn't match their old MaxTrac. They never even noticed that the M1225 dust cover has a diagram molded into it showing the correct orientation.

It's because GMRS licenses are tied to an individual, not to a location. You could be a GMRS License holder in one state, and then have a repeater located in another state, and the FCC would have no idea where your repeater is located. You could also be the License holder, and your sister who lives 2 states away could be the actual user, or her kids. There's sometimes little correlation between the License, the user, and the location with GMRS. If you do want to find out who your local GMRS peeps might be, then yeah just search for ZA within your town/zipcode. Please realize that many of the License names listed might not be actively using GMRS radios, and would probably rather NOT be contacted.

Full disclosure - I've never had a Retevis repeater on the bench to test it out. Judging by the price point (and the design of their portables) it's probably based on a simple Direct Conversion receiver, which are sensitive, but prone to overload. I'd agree that for a simple "quick and dirty" low elevation repeater, it probably does the job for a majority of users looking for their own specific solution. The Retevis is at least less than the cost of a good used MTR2000. I'd really ask anyone looking at a Bridgecom or building their own Woxoun repeater out of 2 mobiles to stop and check out the alternatives available. You really can end up with more for less, if you consider used Part 90 gear. And, that used Part 90 stuff has a resale value when you're done with it. Something you won't really see with used Bridgecom equipment.

Creating a repeater out of two radios that meet Part 95 does not mean you've got a Type Accepted Part 95 repeater. As mentioned, it is also quite expensive compared to the (IMHO better) alternatives. Vertex. Motorola. Kenwood. They all made good Part 90 repeaters. Some will put out at least 50 watts at a 100% duty cycle. Used units are available that will outperform a Bridgecom - and do it at a better price point. They also have a history of performance, along with available support (that you will probably never need).

Yup, no WiFi - no Bluetooth, and lacking GPS. 3 things that might be important if you built a fleet around advanced feature stuff like Indoor Location or Enhanced GPS. Those chips are also missing now in the XPR3500e/3300e portables. The good news is that by dropping those features, they reduced the lead time to months instead of years. A recent customer order for some XPR radios shows a January 2023 expected ship date. The good news is that by getting the order in now, I have already beat the next 2 expected price increases.

I laughed when I read that. The Gman does NOT spend big money on his radios. Most of his Motorola gear was acquired at prices well below dealer cost. I'd venture to say that every Moto radio he owns could be sold today at a profit. Not sure many CCR owners could say the same. But, you're right about receivers.