Using duplexers like this works very well, if they are good duplexers, like the Comet. I use them all over the place as filters.
I have tested them at 80w output on 70cm with a 2m ARR Gasfet preamp ahead of a FunCube Pro + Dongle. Works perfectly and NO intermod, NO desense.
They are an ideal solution to full duplex operations at a very reasonable cost.
I have tested them on an interlaced yagi (with single feedpoint at the yagi) 5 EL on 2m, 8 EL on 70cm, fed with 65' of 1/2" hardline (duplexer in shack), as well as a pair of M2 EggBeaters 7' off the ground fed with 80' of LMR-400. Duplexers at each end.
Performance:
Usable satellite signals at -0.5 deg EL on the tower antenna. No desense, no intermod. SNR 10 dB, Q5 SSB copy both ways. Repeatable.
If that isn't ideal, I have no idea what is. 73, N0AN Hasan
On Tue, Feb 11, 2020 at 7:09 AM VA3ASE via AMSAT-BB amsat-bb@amsat.org wrote:
Good morning,
I was chatting with a friend about his experimentation with amateur satellites and have been pondering if his setup is "safe" for his radio. He is running an FT-847 through a duplexer (diplexer if you want to be pedantic) and into a dual-band vertical base antenna on his roof. Definitely not an ideal setup, but meant to be temporary until time and better weather allow. He has managed to make some FM contacts on AO-92 with it.
My concern is him using a duplexer in this manner while running full duplex. I suppose this is similar to what people must do if using an Elk antenna. I just worry about there being enough isolation between the ports and damaging his transceiver. Are there others using similar setups or is this something to avoid?
73, Alex VA3ASE _______________________________________________ Sent via AMSAT-BB@amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb