[amsat-bb] Full duplex handhelds for AO-85

David G0MRF g0mrf at aol.com
Sat Oct 10 13:08:56 UTC 2015

Hi Patrick

Interesting observation about the Chinese handhelds being able to work full duplex on AO-85 (U/V)
but not on SO-50 (V/U)

I saw some testing figures for harmonic output which suggested some radios use a single low pass with a cut-off just above 70cm, but the 2m transmitter uses the same filter.
This meant the 3rd harmonic from 2m was very high and fell in the 70cm band de-sensing the radio.

What you have proved (hopefully) is that there are no outputs from the 70cm transmitter which interfere with the 2m receiver and that the receiver front end is not de-sensed when transmitting up to AO-85.




-----Original Message-----
From: Patrick STODDARD (WD9EWK/VA7EWK) <amsat-bb at wd9ewk.net>
To: amsat-bb <amsat-bb at amsat.org>
Sent: Sat, 10 Oct 2015 9:34
Subject: [amsat-bb] Friday evening - LilacSat-2, AO-85 (yes!!!), and SO-50...


Even though the KG-UV9D and probably a few other
Chinese-made dual-band
HTs can't work SO-50 full-duplex, they are probably
going to be viable
options for a dual-band HT capable of full-duplex operation
on AO-85 and
other Fox-1 U/V satellites.


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