GMRS with vehicle repeaters/relays

[AronDouglas]

I've finally settled on a radio group for my family (immediate family, and my wive and kids), and thats GMRS. Everyone covered with 1 license. Now onto the research stage

I have hopes of using portables around the houses and farm, with a main base station supporting a repeater (haven't that out just yet), and vehicle radios with mobile relays. I'm liking the Yaesu FTM-3207DR for mobile units, and I already have a few repeater/relay ready handhelds to go with.

My inquiry is this, I'd like to run something like the Pyramid SVR-200 in conjunction with the FTM3207DR, but I dont know to make them talk to one another. Is it even possible to do this with these radios? The intended use is for the low power portables to relay through the vehicles back to base or the repeater. Its probably overkill and unessessary, but it seemed like an interesting idea to run with.

 

[AronDouglas]

Nevermind, I may have answered my own question. I needed to be looking at SVR 200/250 compatable radios such as the Icom F121/221, Vertex VX 3200, or the Motorola Maxtrac.

Next question would naturally be...is this all GMRS compliant? From what I've seen, theres nothing restricting mobile relays like this.

 

[mmckenna]

As you discovered, the Yaesu isn't going to work.
- It is not Part 95 compliant, so it isn't allowed on GMRS.
- It won't have the interfaces you need to connect to the SVR.

For mobile and base radios, the Icom's will work, they have the Part 95 certifications to be legal on GMRS. Some of the Kenwood's do also. Older Motorolas work well. A Maxtrac would be a good inexpensive option, but make sure you understand what it takes to program those radios before you purchase. Maxtrac software is old DOS based stuff and you'll need an equally old/slow computer running pure DOS for it to work.

As for running a mobile repeater...
You would need to contain all this within the limits of your FCC license, which means the existing 462/467MHz frequencies. For a mobile repeater to work well you'll need lots of frequency separation, and you're going to have an extremely hard time getting that with the limitations. The filtering required gets expensive and complex.

I understand what you are looking for, but using GMRS and an SVR and connecting back into your own repeater is going to be a challenge.

How far away from your car do you need to be? There are some other options out there that might work for short distances (1500 feet or so) and would be much easier and cheaper to do. SafeMobile - Wireless Applications - X10DR Microphone

 

[AronDouglas]

Yah, I'm currently going over Part 95 comparable equipment..yay data digging

I am realizing that all this will be rather tight on frequency separation, like you said, its not ideal. I'm not entierly sold on the idea yet, its jsut a fun research project as of now. I am however looking to set up a GMRS network of sorts though (base, repeater and mobile units) just for around the surrounding couple hundred acres or so, or a few miles down the roads. I realize VHF would be better suited for the terrain/woods, but GMRS offers more to my liking. Plus I think the power limits will more than adequate cover my needs.

If I use a vehicle relay, the portables wont be but a few hundred feet away, at best. I could always just walk back to the vehicle to call back instead of being lazy and using my portables. But the concept is just cool and fun. And I do realize that these are older radios. I'm not intimidated by PC programing, or even using DOS. Nothing I havent done before...its what I enjoy about this hobby. Old an new tech everywhere!

 

[llwade]

I am curious, wouldn't a smart phone be a better choice since everyone already has the phone ?
I dont know the first thing about GMRS and it's advantages.
thank you for letting me interrup

 

[AronDouglas]

Technically, yes. There are a lot of options better than HAM orientated tech these days...but thats not why we are into this hobby

I enjoy radios, and I want a direct voice line comms. Smart phones will always be around, and are basically primary use, but a good secondary standby is always greatly appreciated.

 

[kayn1n32008]

Yah, I'm currently going over Part 95 comparable equipment..yay data digging

I am realizing that all this will be rather tight on frequency separation, like you said, its not ideal. I'm not entierly sold on the idea yet, its jsut a fun research project as of now. I am however looking to set up a GMRS network of sorts though (base, repeater and mobile units) just for around the surrounding couple hundred acres or so, or a few miles down the roads. I realize VHF would be better suited for the terrain/woods, but GMRS offers more to my liking. Plus I think the power limits will more than adequate cover my needs.

If I use a vehicle relay, the portables wont be but a few hundred feet away, at best. I could always just walk back to the vehicle to call back instead of being lazy and using my portables. But the concept is just cool and fun. And I do realize that these are older radios. I'm not intimidated by PC programing, or even using DOS. Nothing I havent done before...its what I enjoy about this hobby. Old an new tech everywhere!

Honestly, a GMRS repeater, at the maximum allowable antenna elevation will likely do what you are wanting.

You say a few hundred acres, but also say a couple miles down down the road.

How large an area? A square mile of land is ~640ac. A UHF repeater, should easily cover that and likely a whole lot more. Even with portable radios.

-do you you have any structures like grain silos? If so, look at putting the repeater up on top of one, with a decent antenna.

Honestly, I think you are way over thinking this.

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[llwade]

thank you

 

[Pbartoszek]

Betch Gmrs v1 handset is what I use. Midland MXT115 is my mobile and I am looking at the new Btech GMRS 50x1 as a base

 

[AronDouglas]

300ish acres the property, 600ish is surrounding that is ventured on, which is most of the work load intended for this setup (handhelds to the base station or repeater). As for the vehicles, upwards of 15 miles roughly. And I've got a 40ft tower collecting rust that this will be set up on. But I do have the house (two story) or other structures if needed (not afraid of making a true radio shack either). No HOA to be concerned about, since its all on my own land, and I'm outside city limits.

 

[mmckenna]

I am realizing that all this will be rather tight on frequency separation, like you said, its not ideal.

Well, it's not just that it isn't ideal, it's going to be downright difficult.
Portable <—> SVR on 462MHz
SVR feed mobile
Mobile —>repeater on 467MHz.
repeater —> mobile on 462MHz
Since the repeater will be retransmitting on 462, that's wayyyyy to close to where the SVR is running, and it's going to desense things something horrible. Probably to the point of making it totally unusable unless you are within a few feet of the car. Then you run the risk of the whole thing getting stuck being keyed up and smoking a radio, tying up the channel, running down batteries...
There's a reason why you are not finding much info about this...

The issue is 5MHz of separation is the best you can do. You'll need two UHF antenna on each vehicle, with as much physical separation as you can get. You'll also need a lot of expensive filtering on the SVR side to keep the mobile TX out of it.
It also means that you will not be able to use this with the mobile in simplex mode (462MHz) The system is only going to work when the mobile is using a repeater, if at all.

Setting up the filtering is going to require a spectrum analyzer with a tracking generator, and that's going to be expensive. It's also going to be limited to the SVR only working on one (or very close) 462 channels.

Usually when running a mobile relay like that, you do it in separate bands. Mobile on VHF, relay on UHF, all so you can get enough separation to prevent desense. Since your GMRS license gives you no permissions on VHF, that's not going to work. And you cannot simply use MURS to do this, as linking a licensed service like GMRS into a license by rule service like MURS isn't going to fly legally.

Inband mobile relays like this only really works when you have a whole lot of separation. Recently the FCC opened up a few 172MHz frequencies to allow Part 90 LMR users, (primarily public safety) to do this sort of stuff.

As kayn said, you'd be much better off putting the money that you'd spend on the SVR's, filtering, and all the setup into building out a proper GMRS repeater. Done right, as in high quality (non-Hammy/Cheap Chinese Crap) you should have no issues getting several miles out of a GMRS repeater if the antennas are up high enough.

While the mobile relays are a cool approach, they are a huge headache unless you have enough separation between frequencies. GMRS doesn't give you that.
The long range wireless mic is going to be a cheaper and much easier solution.

Or, just design the system for portable radio coverage. Put the money into a tower and a good antenna.

 

[AronDouglas]

Thanks mmchenna ! Its fun to look into, but its not looking viable. And it makes sense now why most of these relays are set up for crossbanding VHF/UHF. There is the perk of being a HAM, being able to do this...but not for my current set of ideas I've got planned.

 

[kayn1n32008]

300ish acres the property, 600ish is surrounding that is ventured on, which is most of the work load intended for this setup (handhelds to the base station or repeater). As for the vehicles, upwards of 15 miles roughly.

So less than 2 square miles. Easily doable using a repeater and portables, 15miles using mobiles is also doable.

While the mobile relays are a cool approach, they are a huge headache unless you have enough separation between frequencies.

A mobile repeater should be just taken completely off the table for this application.

...design the system for portable radio coverage. Put the money into a tower and a good antenna.

This is the correct course of action

There are lots of UHF repeaters in eBay, that are 50w continuous duty, use minimum 1/2” hardline, keeping it as short as possible. Buy a quality 2 or 4 element folded dipole array. Get your antenna as high up as you possibly/legally can. Properly ground the system. Buy some quality LMR radios with part 95 certification. Buy some quality 5/8 over 5/8 wave collinear mobile antennas for your mobiles.

Stay far away from Tram and Browning antennas. maxrad, PCTel and Larsen are my preferred brands.

For radios my preferred brand is Kenwood. Lots to choose from, and lots are part 95 certified.

TK-860 and TK-880 mobiles are good choices. For a bit more money TK-8180 is also a good choice.

TK-380 and TK-390 are decent portables and super inexpensive in the used market.

TK-3180 are a bit more money, but newer.

All these radios are plentiful in the used market.


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[mmckenna]

All these radios are plentiful in the used market.

And programmable with Windoze based software. Makes life easier.

bonus is that you can program these radios for the 70cm amateur bands as well.

As Kayn1n was saying, it's ALL about the antenna system. Skip the Cheap Chinese/Hammy crap antennas. 1/2" Heliax at minimum. Good duplexers are very important. It's not just the transmitting you need to look at, the ability of the repeater to receive makes a huge difference.

 

[Chrontius]

Yah, I'm currently going over Part 95 comparable equipment..yay data digging

I am realizing that all this will be rather tight on frequency separation, like you said, its not ideal. I'm not entierly sold on the idea yet, its jsut a fun research project as of now. I am however looking to set up a GMRS network of sorts though (base, repeater and mobile units) just for around the surrounding couple hundred acres or so, or a few miles down the roads. I realize VHF would be better suited for the terrain/woods, but GMRS offers more to my liking. Plus I think the power limits will more than adequate cover my needs.

If I use a vehicle relay, the portables wont be but a few hundred feet away, at best. I could always just walk back to the vehicle to call back instead of being lazy and using my portables. But the concept is just cool and fun. And I do realize that these are older radios. I'm not intimidated by PC programing, or even using DOS. Nothing I havent done before...its what I enjoy about this hobby. Old an new tech everywhere!

Actually, I've been planning a similar build over on myGMRS and in some Telegram chats.

What you're really asking for is more like a wireless control head than a repeater -- that's what I (slowly, painfully) pieced together.

Options? I'll list what I've figured out. Brace yourself for a brusquely-written wall of text; I never intended this bullet-point-storm to be seen by anyone else, but I'm encouraged by someone else working on this silly-ass project.

Wireless Microphones

Lupax HM-888
Rebadged Zoxn ZX-777
Illegal AF
Technically sweet

ZOXN ZX-777
Illegal AF
Technically sweet

X10DR
Spendy as ****
Technically sweet
Probably the best option

UNIDEN MK800W

• For UHF-CB

+ DECT
+ Uses 8p8c connector, easily interfaced

Uniden Bearcat BC906W
Like the MK800W, uses DECT.

• Proprietary 6-pin connector
• Only compatible with four Uniden Bearcat radios

Motorola RLN6551
& RLN6544
Barely worth mentioning

• Super speedy
• Proprietary AF
• Not compatible with any civilian radios
• Bluetooth

Hytera SM27W1
Hytera SM27W1 Wireless remote speaker microphone | Hytera Mobilfunk GmbH
Uses ADA-01 adapter for compatibility with old radios

Remote Microphones
X10DR
http://www.wirelesscorpltd.com/solutions/wireless-pacific/x10dr/9-uncategorised/135-x10dr
X10DR® - Secure Wireless Microphone - X10DR Microphone

Zoxn ZX-777
Wireless Mobile Radio Microphone

Honorable Mention:
EnGenius Durafon UHF

However, since then I realized something interesting. We have privileges in 900 MHz even as muggles. You could get a Motorola DTR and a cheap chinese cross-band controller, and if you're feeling like an elegant installation, even a dual-band antenna that handles UHF / 900. Basically you'd be able to talk into the DTR (which has a relatively normal antenna cable) using any compatible 900 MHz radio (but you'd probably favor the new screen-free DLR series; they offer more code-squelch and FHSS modes than the older DTRs, but if you set them to a mode the DTR speaks, they're interoperable). Treat it as a one-watt link budget in and out of the car with an isotropic antenna on the handheld and whatever gain you can get on the mobile repeater.

Bam -- now you've got the performance of a cross-band mobile repeater while fitting (barely) into the privileges of your part 95 license.

I also find it peculiar that this use case is so popular in Australia, and how Uniden is in such a great position to bring it to the US… but doesn't.

 

[Thunderknight]

Nevermind, I may have answered my own question. I needed to be looking at SVR 200/250 compatable radios such as the Icom F121/221, Vertex VX 3200, or the Motorola Maxtrac.

Next question would naturally be...is this all GMRS compliant? From what I've seen, theres nothing restricting mobile relays like this.

Remember, if the SVR is transmitting on GMRS frequencies, that SVR needs to be part 95 GMRS compliant. too. It's not enough to have just the mobile radio be compliant, but the SVR too if the transmitting (vehicle repeater) frequency is GMRS.

 

[AronDouglas]

I guess thats a technicality, to be honest @Thunderknight . It receives a signal, then exports to a Part 95a radio, which does the actual transmitting. But lets not split hairs. It is however part 90 and Part 22 compliant. It operates within the GMRS frequencies (not above or below), and its a max of 2 watts. So its all compliant, just not paperwork compliant. And since its not a radio per se, I down know IF it could be 95a compliant.

SVR-200M LOW POWER VEHICULAR REPEATER User Manual SVR_MAN.PDF Pyramid Communications

@Chrontius Telegram chats for ham radio gear? Cool, been looking for some! The wireless mic is a very ingenious idea, definitely demands more attention.

The majority of the challenge is finding Part 95a toys to mess with. But with a LOT of research, I've got a nice list of radios. So technically I can make my own small repeater....just gotta learn about filtering now -_-

 

[Thunderknight]

Not really a splitting of hairs. If you are using the repeater one-way, e.g. to take the portable's signal in and use the mobile to transmit it out at higher power, then the SVR is not transmitting on GMRS. However, if you have setup for both ways, so that when the mobile receives audio, it goes through the repeater and is transmitted at 2W to the portable, then the SVR is transmitting on GMRS.

 

[n1das]

A mobile GMRS repeater can be a conventional GMRS repeater installed in the vehicle and powered by the vehicle instead of at home or at a tower site and can use a single antenna. A mobile GMRS repeater is handy to have as a local on-site repeater wherever you go.

15 years ago I homebrewed a GMRS repeater with Icom mobiles and a duplexer (notch only type, aka mobile duplexer) and used a single UHF antenna on the roof of the car. The mobiles in the repeater setup were powered by the car. The Icom mobiles had basic repeater control functions built into the mobile for making simple repeaters so no external controller was needed. My repeater operated on the 462.625/467.625 GMRS frequency pair, same as what my other GMRS repeaters used. I used DCS/DPL instead of CTCSS/PL because I expected other GMRS repeaters I might encounter wherever I go are more likely to use CTCSS/PL. I was careful to make sure there were no other GMRS repeaters in use on 625 in the area. The end result was I always had an on-site GMRS repeater to use wherever I went. It was great at ham flea markets and shopping mall trips. When parked at shopping malls, the repeater helped handhelds with coverage inside the mall. In one case, a GMRS-licensed friend was mobile and a few miles away from the mall while I was deep inside the mall with my handheld and we were able to talk without any problem. Repeaters are usually located far away from where handhelds using the repeater are located but in this case the repeater was located in the best spot for handhelds deep inside the mall while still working for the mobile that was a few miles away.

The mobile GMRS repeater was later repurposed as a 440 ham repeater and I added a controller to it for the ham repeater functions. The repeater has since been replaced with a DMR repeater on 440.

 

[Chrontius]

Dude, that's awesome. That's exactly what I've been wanting to build, ad been told I was nuts for trying on occasion.

Can you tell me what kind of Icom mobiles you were using? Any other secrets to building such a gadget? What questions would I ask if I knew, but don't even know to ask?