Hello Andy,
The issue is the third harmonic of the 2M uplink being "heard" by a sensitive receiver setup on 70cm. Here is a link from our old friend Tony, AA2TX (SK), that is still applicable today.
The idea is to filter! It may take something on the transmit side and the receive side, depending on your station. Too many variables--but this will let you begin to work towards reducing the problem.
https://www.amsat.org/a-simple-desense-filter-for-mode-j-satellites/
There are also some nice bandpass filters that can be used, but they are a good bit more expensive.
73, Mark N8MH
On Sun, May 24, 2020 at 5:16 AM Andy Brian via AMSAT-BB [email protected] wrote:
Hi
any good suggestion how to reduce noise from VHF TX on receiving on UHF fo RS44
I'm using two antenna antena 8meters away each other but is hard to hear anything when TX.
73 Andy _______________________________________________ Sent via [email protected]. 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