I would be more inclined to blame the dual-band mobile whip... It is probably designed to provide gain toward the horizon, and likely does not radiate (or receive) well at elevation. While I have had satisfactory results using a 1/4 wave whip for 2-meter up- or downlinks, it did not work well for UHF up or down, and I never had good results on either band using a dual-band Larsen mobile antenna.


73,

George, KA3HSW


On 9/19/2021 3:06 PM, John Geiger wrote:
Over Labor Day weekend I went out of town and took the FT847 with me hoping to hand out Em15 on a few satellite passes.  Instead of taking 2 mobile whips with me, as I have in the past, I decided to try and simply things by running 1 dual band mobile whip and a diplexer for the radio.  I bought a Comet CF-416 Diplexer which is supposed to have 60DB of isolation between ports.  Results were less than expected, though.  I really couldn't hear myself on the satellite downlink at all, where I usually have no problem with separate antennas.  Have others used a diplexer with 1 antenna with good results?  What might I be doing wrong?  Any advice on how to make this setup work?

73 John AF5CC