Dual band mobile used as a Repeater

Discussion in 'Survival Communications' started by melbo, Sep 23, 2005.

  1. melbo

    melbo Hunter Gatherer Administrator Founding Member

    I saw a discussion once about a guy that had a 2 meter handheld and could walk miles away from his truck while using the Mobile rig in the truck as a repeater, re-broadcasting for 5X the distance.

    Would be interesting as you could have 2 parties then 20 miles away from each other, yet within the 10 mile range of the "Repeater"

    We need a Ham here... WHere's gunnut1?
  2. monkeyman

    monkeyman Monkey+++ Moderator Emeritus Founding Member

    and with another truck there to relay it you could keep the signal going that much further to the next station.
  3. Clay

    Clay Monkey+++ Founding Member

    It's called cross band repeat and it is some cool stuff. Basicly you would have a mobile radio that is dual band/dual recieve set to recieve on 70cm and transmit on 2 meters. Then your HT would be on 70cm and the mobile radio in the car would be the repeater.

    I am going to replace the 2 meter radios in both of my vehicles so I can do this and also put one in the house. That way while I am working outside I can still use the radio, because my house is just far enough away from the local repeaters to work.
  4. Brokor

    Brokor Live Free or Cry Moderator Site Supporter+++ Founding Member

    We have numerous topics on this at the SWS forums that I started for a friend of mine who is a communications GENIUS, and goes by the name "Smurf". It's his project, basically...

    Anyway, a repeater is some wonderful kit if you know how to use it effectively. Here is one of the posts that Smurf made to help us better understand the repeater in a survival fashion:

    We have strict joining rules, and we keep all our posts that contain sensitive information in password protected forums. Basically, the forum is not highly active, and is intended only for serious people who wish to learn more about land navigation and how to communicate with one another when the proverbial Fit hits the Shan. [beer] i spend a minute or two there daily just to check in, and you guys are all welcome to register if you want to. I spend about 100 times more time here at survival monkey, though. The idea with the SWS forums is to create a strong and clear line of communication, or a brotherhood so to speak. http://www.sws.forcedownloads.com I didn't want to spam the website, just fill in the information and let you guys know that we have some serious answers if you need them. :D
  5. Clay

    Clay Monkey+++ Founding Member

    The glory of having it in your car is it goes where you go, and you don't have to set it up every time you move it. Not only that but a moving target is harder to DF.
  6. melbo

    melbo Hunter Gatherer Administrator Founding Member

    WHat radio models are you looking at for this. I love the idea of being able to wander 6-8 miles from the Truck with the Yaesu handheld and still be able to punch out with Mobile strength!
  7. Clay

    Clay Monkey+++ Founding Member

    Icom 2720H, Kenwood TM-D700A & TM-V708A, Yeasu FT-8800 & 8900

    All good radios in the $350 to $500 range. I'd buy which ever I could get the best deal on.
  8. melbo

    melbo Hunter Gatherer Administrator Founding Member

  9. melbo

    melbo Hunter Gatherer Administrator Founding Member

    No SPAM taken Brokor... I'm always looking to network ;)
    Always give us the links you feel are important....
  10. ghostrider

    ghostrider Resident Poltergeist Founding Member

    Two questions, do you have to use an attenuator for an impedence match, or to knock the signal down enough for the transmitter, and it looks like this could be done with SMA connectors and cables to make it modular. Plug and play, if you will.
  11. ghrit

    ghrit Bad company Administrator Founding Member

    Very old thread moved to comms and bumped for any updated thinking.

    The idea of using a mobile radio, say in a car, as a repeater is easily accomplished with a handheld on 70cm and repeating on 2M or vice versa. Get yourself lost or injured while carrying the h/t ---
    Last edited: Sep 21, 2016
    hitchcock4 and Ganado like this.
  12. BTPost

    BTPost Stumpy Old Fart,Deadman Walking, Snow Monkey Moderator

    The Kenwood TM-D700 has been updated, twice since then it is now either a TM-D710A, or TM-710GA... The 710A needs an external GPS Input for APRS... Where the 710GA has the GPS built into the Control Head.... They are basically the SAME Unit, but the control Heads and T/R Units are NOT Interchangeable... I have 4 of the 710As... One as a Base, one in the Replacement for the RED Toyota 4X4 Pickup, One in the Rhino 660, and a spare that I bought for EMP Backup.... When the MARS Mod is done they have Tx/Rx coverage from 136 - 174 Mhz & 420 - 470Mhz, plus they will Receive in the 108 - 136 Mhz Aircraft Band.... They are 50 Watt Radios, on Both Bands... I gave away the D700 I started out with, for the better D710As.... I have a Control Head for a D-710GA that i played with trying to make it work with a D710A T/R Unit... No Go, but if anyone needs one this one is surplus to my needs, at this point...
    We also have the Kenwood TH-72A Handhelds.... which do allow for Mobile Repeater OPS, with the D-710As.... They work well, for us in this service... These Handhelds also are Full APRS Capable, with a Built-in GPS... and when the MARS Mod is done, they have the same Tx/Rx Range as the D710As, without the 108 - 136 Mhz Rx Band... and Both Models have 1000 Memories, to store all the on-Ham Frequencies you will ever need. (Marine, MURS, FRS/GMRS, EMS, Public Safety, Etc)
    hitchcock4, Dont and Ganado like this.
  13. hitchcock4

    hitchcock4 Monkey++

    Last November, I got the Kenwood TM-V71A since it also has the capability of dual-band repeater. But it doesn't do APRS and cannot connect to a GPS unit in any way that I am aware of.

    Ham Radio Outlet has it right now for $344.95 KENWOOD TM-V71A Transceivers Mobile Dual Band 2m-70cm (price includes the $25 rebate from Kenwood, make sure to print the form, etc). Kenwood runs a rebate on that radio at least a couple times a year, so if you miss it this time, look again toward the end of this year or beginning of next year.

    This was my first (only right now) mobile radio. I really like the dual-band repeater capability but I have only used the repeater function to test it out.

    The TM-V71A is about $220 cheaper than the TM-D710G ---KENWOOD TM-D710G Transceivers Mobile Dual Band 2m-70cm (link shows price with rebate included). I'm not knocking the features of the TM-D710G, but just pointing out that the TM-V71A is cheaper for those just getting into ham radios and still want the repeater function.

    If you want to see a quick video of the cross-band repeat on this particular radio, please check out
  14. BTPost

    BTPost Stumpy Old Fart,Deadman Walking, Snow Monkey Moderator

    @hitchcock4 The TM-V71A uses the same T/R Unit as the TM-D710A Radio.... The only difference is the Control Head, where all the APRS and GPS Ports are located... If you can find a D710A Control Head, or an RC-D710A, you can upgrade your rig for APRS. You can NOT use a Control Head from the TM-D710GA, as those will NOT Operate and of the Older T/R Units...
  15. ghrit

    ghrit Bad company Administrator Founding Member

    to add: Kenwood TH 6a pairs nicely with the TM V71. At least it will once I get the instructions figured out later this year. I'm less certain that APRS cannot be arranged on a V71, but doing so will require using a computer or other external as yet unidentified (by me) widget to git 'er done.
  16. BTPost

    BTPost Stumpy Old Fart,Deadman Walking, Snow Monkey Moderator

    Yep, The TM-V71A, or any other VHF Radio, will do APRS, IF you attach an external Packet Modem and some kind of APRS Computer... I like the Built-In Capabilities, so that is why I went that direction.... Around the AoO I use a UHF Frequency for APRS between the Base, Rhino, and the two HandHelds, and a VHF Frequency for Comms... This allows me to track where Guests are, when they are out and about, and carrying the HTs, for Comms back to the cabin.... It has come in handy, in the past... Being able to see where they are, when they got stuck, driving Off-Trail, and couldn't tell me where they were....
  17. Idahoser

    Idahoser Monkey+++ Founding Member

    To visualize what could be done with these VHF/UHF rigs as the OP was discussing -
    Drive to the edge of the wilderness and set up the mobile to crossband repeat. UHF will be your walking around radio, VHF will be the local club's repeater.
    Now from your tent, you talk to the H/T in your hand, the truck sends it to the repeater, the repeater sends it to the entire community. And, if it's set up on one of the internet services, somebody across the world could hear you. All of this works in reverse too, of course, you will hear the drive-time chat on the repeater as well.

    just to add another wrinkle, I remember there was a Kenwood HF transceiver that would interface with a mobile or handheld this way too, so you could remotely operate on HF through your handheld VHF/UHF... no repeater distance limitation then. I think it allowed you to actually change frequencies etc. via the handheld.

    As to whether a rig can interface with a GPS and/or has one built in...
    I looked into APRS a while back, got a TM-D700A and the Garmin and the special cable and all that...
    but I ended up deciding I wasn't really interested in broadcasting my exact location for anybody who might be interested.
    ghrit likes this.
  18. BTPost

    BTPost Stumpy Old Fart,Deadman Walking, Snow Monkey Moderator

    @Idahoser That is called Kenwood "Sky Command" and most of the Kenwood DualBanders can do that when connected to most of the newer Kenwood HF Radios.... (TS-2000, TS-480, TS-590, TS990)
    Idahoser likes this.
  19. Tempstar

    Tempstar Monkey+++

    All good info. Just keep the conversations short while cross banding because the cross band repeater is transmitting both sides of the conversation. My '71a gets really hot after a 5 minute chat.
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