11 ms·
Sounds like you're already on it, but anyone who is thinking of trying, (1) make sure you are correctly licensed, (2) make sure you only transmit while you can
by tomfanning 6y ago
Sounds like you're already on it, but anyone who is thinking of trying, (1) make sure you are correctly licensed, (2) make sure you only transmit while you can clearly hear the downlink, and (3) make sure you are listening to the downlink while transmitting (full duplex) to ensure you aren't stepping on other people.
- mlyle 6y ago> (3) make sure you are listening to the downlink while transmitting (full duplex) to ensure you aren't stepping on other people. If possible. Not everyone has fancy-pants cross-band full duplex capability. I know a couple HTs will do it now, but this is still a bit exotic. This is the strongest space amateur FM repeater ever; surely those of us who are better equipped can use SO-50, etc, without issue, and we shouldn't get too mad if there's a little less-than-ideal operation on something as newbie-friendly as this.
- dx4100 6y agoMy cheapest HT can do this. And my 20 year old radio can do it. So not sure about "exotic"
- jimnotgym 6y agoWhat radios are they?
- nickysielicki 6y agoKenwood's TH-D72, TH-V71A, and TM-D710G can do it. An incomplete list of full duplex vhf/uhf cross-band FM radios can be found in this reddit comment: https://www.reddit.com/r/amateurradio/comments/97jhik/getting_into_satellites_need_full_duplex_uhfvhf/e48mxpf/?context=3 https://www.reddit.com/r/amateurradio/comments/97jhik/gettin...
- jimnotgym 6y agoSure they can, but I wondered what cheap radio the OP was talking about that runs full-duplex?
- nickysielicki 6y agoYeah, there really aren't any. The cheapest option is two unwieldy independent Baofengs.
- tomfanning 6y agoA second-hand Kenwood TH-D7 is an alright choice.
- mlyle 6y agoTM-V71A isn't a HT, nor is a TM-D710G. For a new ham who's scraped together some coins and gotten an HT, the only options that I'm aware that will work are the TH-D72. AFAIK the only options are TH-D72 and Wouxun Dual.
- nickysielicki 6y agoWhile not an HT, the TM-V71A is very popular for LEO usage because you can easily ramp up to 25W when needed. See this video of John Brier KG4AKV with his front-backpack TM-V71A mount. https://www.youtube.com/watch?v=w7Ukh_nT2Tg https://www.youtube.com/watch?v=w7Ukh_nT2Tg
- mlyle 6y agoI don't know of anything except Wouxun Dual and TH-D72 that can do it (that are HTs). If a D72 is your cheapest HT, then well, congrats.
- tomfanning 6y agoDual watch, or full duplex? My decades-old FT-470 can do true full duplex too, but it's less common in current radios. Just dual watch now.
- mindcrime 6y agoFair point, but FWIW, even a little Baofeng F8HP[1], which sells for around $70 can do cross-band like this. I'm not sure this feature really qualifies as "exotic" these days. [1]: https://www.amazon.com/BaoFeng-BF-F8HP-Two-Way-136-174Mhz-400-520Mhz/dp/B00MAULSOK https://www.amazon.com/BaoFeng-BF-F8HP-Two-Way-136-174Mhz-40...
- nickysielicki 6y agoThat baofeng isn’t full duplex, they’re using an incorrect definition. It can’t transmit and receive simultaneously on different bands.
- mindcrime 6y agoFair enough. I was just thinking in terms of the "not walking on people" thing... to achieve that you don't really need "true" full duplex, you just need the ability to configure a cross-band channel. Sure, there's a race condition if two people start transmitting at nearly the exact same instance, but in practice that doesn't seem to be a big problem.
- mlyle 6y agoDo you work satellites? It's a really big problem-- people who can't hear whether and how well they're getting in, interfering with people who are. There's often dozens of people contending for time on a little 7 minute pass. A QSO finishes and everyone keys at once to get in. Someone has bad doppler correction on the uplink and isn't making it in and you can't really tell who it is or tell them. Someone else with a PL tone mistake jams everyone. Someone else can't get through well enough to be intelligible, but still can cause big QRM and confusion for everyone else (is that someone answering? is that person successfully having a QSO and -I- am hearing badly?). Just about every radio will do what you describe. You don't -want- a cross-band channel usually, because you want to tune separately for TX and RX. (I've also done it where you make many, many channels with pairs of uplink and downlink frequencies). With real full duplex, satellite is, say, 5x easier -and- you stop being disruptive to other users of the sat.
- tomfanning 6y agoFancy-pants cross-band full duplex can be achieved with two £15 Baofeng UV-5Rs and a DIY duplexer with about 2 components on it (or just two antennas on one boom). That's my setup - I'm not better equipped than that.