Dale,
As has been pointed out, there have been many HTs over the years that allow for cross-band full-duplex operation. This was actually a more common feature in the 1990s, and has gradually disappeared from HTs since then. A few years ago, Andrew KE5GDB had a list of HTs and other radios that supported cross-band full-duplex operation on his web site. That web page is gone, but lives on in the Internet Archive's Wayback Machine at:
http://web.archive.org/web/20090724094403/http://www. thathamkid.com/website/ham-radio/full-duplex-radios
For HTs, you could add the TH-D72 to this list, which came out at the end of 2010.
In addition to those HTs, there are a few others that allow for cross-band full-duplex operation in one direction, where you are transmitting on 70cm and listening on 2m. I wrote a bit about a few of the Chinese-made HTs that are able to work AO-85 full- duplex in a series of posts here on the -BB in late 2015. One message I posted in December 2015 that had links to the other posts I made about those radios is available at:
http://amsat.org/pipermail/amsat-bb/2015-December/056269.html
The 70cm receivers in these Chinese-made HTs suffer from desense whenever you transmit on 2m. These radios can be programmed with groups of memory channels to work V/U FM satellites like SO-50 half-duplex, or you could use the two VFOs to do that without the need to program memory channels.
Using separate radios for uplink and downlink is also a good way to have a full-duplex setup. Many have even used a pair of the inexpensive Baofeng-type HTs to have a station capable of full- duplex operation, or one Baofeng-type radio paired with an HT from one of the traditional ham manufacturers.
73!
Patrick WD9EWK/VA7EWK http://www.wd9ewk.net/ Twitter: @WD9EWK
On Thu, Mar 9, 2017 at 4:25 PM, Dale Kubichek via AMSAT-BB < amsat-bb@amsat.org> wrote:
Everyone wants 'full duplex', I've not seen a dual-band HT that can do 'real' RX while the PTT is pushed, period!