FULL DUPLEX HTs

Discussion in 'Satellite and Space Communications' started by KA0USE, Sep 5, 2021.

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  1. KA0USE

    KA0USE Ham Member QRZ Page

    i recently bought an arrow leo antenna with diplexer.
    before that i bought the recently upgraded baofeng dual band gt-5r (at a paltry $25/free ship).
    i mistakenly thought 'dual band' = 'full duplex'.
    well, to make up for that i bought a second gt-5r ($21 on sale/free ship), but of course i'll need a
    splitter connector to connect the 2, or disconnect the diplexer and attach longer coaxes.

    i also have an 817nd and got excited thinking it could be full dupe. wrong.

    i'm trying to keep things simple and the weight down.

    i've googled duplex hts and got a ton of baofeng ads sans 'full duplex'.

    suggestions, puhhhh-lease? i'm sinking.

    thinking also of getting a kneeboard for record keeping. i have a suitable tripod, and arrow kindly
    cut/ threaded a 1/4x20 hole in the boom for it.

    THANKS MUCH!!
     
  2. WD9EWK

    WD9EWK Ham Member QRZ Page

    I maintain a spreadsheet of radios - handheld, mobile, or base-station - capable of full-duplex operation for satellites. Maybe that can help you out.

    Have you considered using an audio recorder, or an audio recording app on a mobile phone or tablet? Might help with having your hands free for the radio and (maybe) antenna.

    Good luck, and 73!
     
    W9YW, AG5DB, KA0USE and 2 others like this.
  3. K4BAD

    K4BAD Ham Member QRZ Page

    In the
    . In the spirit of keeping things simple I would concentrate on connecting the 2 Baofengs to the Arrow antenna by disconnecting the duplexer and using longer coax….LMR 240UF coax should work.

    Before attaching antenna to tripod,you might manualy hold and move the antenna to receive a satellite.This will give you a”feel” for what’s required for satisfactory operation.

    Also,suggest you take a look at YouTubevideos on sat.operation.Some are better than others.

    Good luck chasing the birds!

    73 K4BAD Harry
     
    WE4B likes this.
  4. KS1G

    KS1G Ham Member QRZ Page

    Patrick's list is an excellent resource. That said, disconnect the Arrow diplexer (or use as a "Mode J" filter?) get the longer feedlines (my preference is LMR-240UF) and you have **everything** you need for a full-duplex station, just use 2 radios. Patrick's list might show if the GT5R is susceptible to desense on 70cm when transmitting nearby on 2M. I would give the FM birds a try using a GT5R for transmit and the 817 for receive (likely a much better receiver). I personally find it easier to manage 2 HT-size radios vs. a single full-duplex, but that's my preference). Future: Add another 817/818/705 (is brand-mixing "allowed"?) or find an 817 with blown finals and you have a full-duplex CW/SSB/FM setup. A lot of folks are quite successful using the Arrow hand-held; if you want to use the tripod, plan on adding a counter-weight/extension to balance the weight of the antenna (many tripod heads do not handle it well). Several earlier threads have a lot of pictures of tripod setups if you need ideas. https://forums.qrz.com/index.php?threads/show-your-satellite-antenna-tripod-setups.712808/ keeps getting new posts and there are also ideas here: https://forums.qrz.com/index.php?threads/arrow-antenna-mounted-and-outfitted.625249/ (I particularly liked the use of McMaster-Carr bearings to allow rotating the antenna for polarization - see W9AC at post #33.) There are some great rig suggestions and and operating tips in the 2nd thread. And especially starting out, YOU DO NOT NEED A BATTLE STATION (aka Arrow + Tripod + everything else you need on it) to work satellites. Better to figure out what works for you!

    Kneeboards/wristboards may work for you - For LoTW, all you need to log semi-real-time is the other station's call and approximate time. I keep running out of hands so voice recorder in parallel or series with RX radio and headset is what I think most ops end up using (and again, many different ways to accomplish the same goal).

    Good luck & 73s, hope to work you on the birds.
     
    KA0USE, WE4B and K4BAD like this.
  5. KA0USE

    KA0USE Ham Member QRZ Page

  6. W9WQA

    W9WQA Ham Member QRZ Page

    think my hw 24ht is f d
     
  7. N4UFO

    N4UFO Ham Member QRZ Page

    Yes, but keep in mind that those were likely tested talking to repeaters... that is a FAR CRY from trying to receive a weak downlink from a satellite. I am fortunate to own an Icom IC-W32AT and use it from time to time on FM sats. And while it is full duplex, on SO-50, I cannot hear myself on the downlink. It is unfortunately a model that came out after some filtering changes and while I can hear repeaters, etc. on UHF while transmitting on 2m, the 2m transmitter wipes out the weak 1/4 watt downlink of SO-50. All I hear is noise. No different than using two HTs. It was fine on the AO-9x birds, but they are not in the best shape at the moment.

    A working list of full duplex radios is here... refer to comments for additional information: https://herrons.com/satellite-radios/
     
  8. KC3RN

    KC3RN Ham Member QRZ Page

    I would leave the diplexer in place. Use it on your downlink radio as it will help with the desense issue. Just disconnect the diplexer feedline for the uplink antenna. Connect your uplink radio's coax to the antenna. Good to go.

    I have a Kenwood TH-D72 (full duplex) HT that I use for the satellites, but I prefer using my Yaesu FT65 for uplink and an Icom IC-R30 for the downlink. The R30 has a built in recorder so it makes my life a little simpler. I've used the R30 with my FT-817 as well, but like KS1G said, two HT's are a little easier to manage.
     
    KS1G and KA0USE like this.
  9. WD9EWK

    WD9EWK Ham Member QRZ Page

    I don't have any Baofeng radios in my spreadsheet.

    My list is not a comprehensive list of radios and whether or not they are capable of full-duplex operation. That would be a huge document, especially with the Chinese-brand radios and their many variants on the market. Just those radios that are capable of full-duplex operation. I have tried many of the radios listed there, added some based on reports from other satellite operators, along with those radios KE5GDB had on his list from 2009 (the starting point for my spreadsheet).

    I have noted some radios that are capable of full-duplex operation on some satellites (U/V, or L/V when AO-92 supported that configuration) but not others (V/U). I have also tried to note if certain radios need a modification to transmit on UHF below 438 or 440 MHz - a common issue with US/North American versions of many amateur FM transceivers covering the 70cm band made into the 2000s. I don't have the modification details for those radios in my spreadsheet, as those are usually available online.

    73!
     
    KA0USE likes this.
  10. KA0USE

    KA0USE Ham Member QRZ Page

    THANK YOU! i was starting to bleed money and feared even more.
     
    KC3RN likes this.

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