tweiss3

What radio were you using? I haven't made it successfully, but my understanding is that even with Doppler, the frequency does change throughout the contact. I doubt you had too much gain, as those I know that make those contacts do so with Yagi/Beam antennas with gain over 11dbi. I would guess you were slightly off frequency on the receive, but on the marker on transmit. I know my IC9700 has an auto tracker than can track the received carrier and adjust as it moves with the Doppler shift, but I don't think any other radio has that. Others use the computer to adjust on the fly.

I found it. It only "doubles" the range in 1 direction, and they use 20' of separation which gives 47dB of isolation. It is not bi-directional, so it is kind of a pain in the rear, and won't help most situation, but what do you expect from license-free solutions.

I think any implementation would have to come from Motorola directly, or whichever FHSS radio manufacture you are using. That being said, lets talk about a theory that might work as a repeater. My understanding is the radios utilize at least 50 frequencies, and hop about 50 times a second. The privacy is caused by changing up the hop set (order and number of frequencies), which means any repeater would have to be programed identically to the radios, but that's not a problem, that's typical of repeaters. Two problems exist, which we have to overcome: 1) At any given time (snapshot), the radios are using a single frequency for both receive and transmit. This could potentially be overcome by having a small delay in the re-transmission, say 2 hops behind the transmitting radio. Any radio in range of the transmitting station would continue to sync and receive from that station, stations outside that range would instead be synchronized and receive from the "repeater" station. Problem solved? 2) Second problem is, a traditional repeater usually has a fixed frequency set, and uses a duplexer to separate receive from transmit to eliminate desense in the receiver. The alternative is two antennas. Since 902MHz is such a high frequency, vertical separation can be relatively small and provide good isolation. 1 foot vertical provides 27dB isolation, and 2 feet increases that to 39dB, more than enough decent selectivity can overcome. Make sense? I think the theory would work, practice might be a bit harder to accomplish. There there is getting 15C certification for the "repeater".

I just tried to read through the rules (15C), and I don't see this being permitted. They even went as far as limiting the power, antennas and the gain on any antenna in an attempt to limit range. Also, I don't see how this would even work, its not operating on a frequency split, so it would have to be a store and forward type repeater, which might make the receiving stations hear the transmitted message twice.

I have 1.2, the base has D-Star, the HT does not. 900 is less expensive to get into.

Considering how empty the 902 ham band is, run P25 and nobody will hear you anyways.

The FAA has a notice criteria tool: https://oeaaa.faa.gov/oeaaa/external/gisTools/gisAction.jsp?action=showNoNoticeRequiredToolForm I have had to file notice for buildings and even substation power lines before. I have also used that tool to prove buildings are not tall enough to extend into FAA airspace.

My understanding is they want to see the testing to include more points directly in the GMRS range, which typically is not included in the wide range part 90 testing. The secondary part is they probably don't want to deal with the whining and support to the typical licensee with the programming software. The usual cast of characters that whine when they have to downlead the free software/driver from the web to use the cable provided in the box and program their radio couldn't fathom paying a few real bucks for the correct cable and software.

The only reason main stream manufacturers abandoned it is the changes to get part 95 approval. When a radio gets Part 90 approval for 403-512MHz, they used to be able to fill out one form, and use the existing test to get Part 95 approval. Now, they are requiring a entire second test and full set of submission to the FCC. For the percentage of the market that GMRS is, they all said no thanks and walked. Heck, similar can be said for Part 80 (marine), but manufacturers will apply for that one because the market is much bigger than GMRS. There are many commercial radio needs for Marine service radios with IS ratings (XPR7550e comes to mind). EDIT: For what it's worth, if it gets tested and approved in Part 90 for a block of frequencies that include the GMRS set, I see no reason it shouldn't be allow to get Part 95 on the same test. Granted, it may be stuck at narrowband, but that's still better than having to run another test.

When you are up at 1500 AGL, often times the entire repeater is cabinet mounted that high on the tower, with a very short coax run.

QRP phone is fun as well, while it's a bit difficult, the challenge can be rewarding. I did upgrade to the 705 for my QRP station, because the package is pretty dang complete. Having a waterfall can be a huge benefit when searching out contacts.

Check the pins, and rub all the dirt off the contacts on the radio side.cn

True, but if you turn it down to 1W, and use physical separation of the two RF decks, good commercial equipment should have enough selectivity to have no issues when the VX1000 is on 1-8 and the radio is on 15-22.

Another option, the Vertex VXR-1000 "in car repeater" has Part 95 approval, and you could connect it to the back of your commercial radio's DB9/25 connector and have HT access to your base station throughout the house.

AGREED! A TK-890with dual heads sounds like a good option

Why don't you look for a radio that has a dual control head option.

I'm going to say, this is possible in a very limited capacity, if you are to use a single SIMPLEX channel on each radio, and they cannot be the same, you could then possibly get a full 6 can duplexer to work. What you are really looking to do should be done with a single RF deck commercial radio, run dual heads, and enable dual watch/priority watch. On second though, I found what you are looking for, a T/R switch: https://mfjenterprises.com/products/mfj-1708b-sdr (this one doesn't work well in the UHF commercial band) You would have to choose which one to use to listen, and the other would be the receive & transmit radio. You CANNOT switch between the two without disconnecting and reconnecting coax.

Sounds like it might be fun, if I could ever get the hang of CW and truly learn it. I know quite a few people that do really well QRP CW.

There are supposedly a group of guys that are doing 10M YSF on the 991As, and I would love to try D-Star on on 10M, just haven't lined up the time with anyone yet. On the commercial side, there are a few VHF-Lo band repeaters, one based off Kenwood's NX5xxx lol band deck, supposedly will do P25 and NXDN. I'd love to put up a 10M digital voice repeater.

Like FM radio. A few weeks ago while listening to the 10m opening, I heard a guy loud and clear from Alaska who was supposedly running 50W. If you didn't know better, you wouldn't be able to tell it was 10M

Glad you figured it out. I was going to say, give the manufacturer a call. I know of one tower that was having issues, ended up needing a cable set made by the manufacturer as length was critical to the 1/32 of an inch, and it worked as designed then.

We had one DMR Repeater in the area that someone unlicensed put up. I gave them names, FRNs and addresses (they were hams using their ham DMR ids) and the FCC said thanks but we aren't going to touch it. I ended up talking about it with a few local hams, they knew which tower it was on, and the tower owner pulled the plug. I'd like digital to be approved, the coverage distance improvement is huge, but who knows.

It seems this question pops up on other websites about ever 6-10 weeks or so. This is what I have found, but have not tried it at all: EDIT: I'll pm you the instructions I found Historically, if you can find the files referenced above, you still have issues with current operating systems. Everyone who has tired it on their own lately has ended up utilizing option 4 and calling it a learning experience. I recommend you Give a few radio shops a call.

That antenna requires a ground plane, in GMRS's case, you need atleast 6" or ground plane in all directions. You could place a 12" diameter metal disk between the magmount and puck antenna, as long as the center pin still makes contact. Your crossbar isn't going to be enough to provide an adequate and effective ground plane. I've experienced issues with middle of the roof install of a magmount and a ground plane dependent antenna. When I went to a no-ground plane antenna, it helped significantly.

Can't you program it with CPS2.0? I've never gotten my hands on one, and I don't have a blank codeplug to take a look.