[mindcrime]

Fair 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]

Do 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.

[mindcrime]

Do you work satellites?

I'm just getting started in this world.

A QSO finishes and everyone keys at once to get in.

Aaah, interesting. I've never been around one of those situations and it never occurred to me that enough people would be doing something this niche at one time for that kind of jam-up to occur.

Thanks for the heads-up. I guess maybe I'll look at investing in a real full-duplex radio at some point. Probably a mobile though, not an HT. Getting a decent mobile rig for my truck is next on my ham wish-list anyway.

[tomfanning]

The experience operating sats is very different depending on where you are on the globe. Advice that's okay in one place may be bad advice in a different location.

One final heads-up, the vertical antennas typically fitted to vehicles make really poor satellite antennas because you can easily emit enough power to make it into the sat, but there isn't enough directional gain to hear the downlink, so you're back in the same situation. A dual band yagi antenna really is the way to go. You also don't want to use a mobile radio with a yagi unless it's turned down to low power, because of RF exposure limits at VHF/UHF. A typical portable station is a dual band yagi (e.g. Arrow II) with one FD or two HD handheld radios, a headset, and a voice recorder, and a typical fixed setup is az-el rotator with computer control, dual circularly polarised X-quad yagis, masthead preamplifiers, and Doppler control of uplink and downlink frequencies.

[mlyle]

Satellites are a ton of fun! You should go for it. You -don't- need a full duplex radio to get started. It just helps and makes it easier for everyone else, too.

If you decide to... it's important to just plan to listen to a few passes and get to hearing the satellite really well before you try to transmit, though.

[tomfanning]

Yes, you absolutely do need true full duplex to (a) know you're getting in, (b) not step on anyone else, (c) know when you're being stepped on, all of which are really required to operate effectively and courteously.

[mlyle]

Let's not excessively gatekeep things. Someone who is curious and wants to try a satellite once shouldn't need to buy new equipment. A dumb HT with a simple whip is enough; just keep your transmit duty cycle low and try hard to not step on people.

If I followed this advice a couple decades ago I'd never have gotten into operating sats. Yes, now that I'm equipped for FD I'd never operate without it, but..