View Single Post
Old 25th Apr 2021, 11:51 pm   #21
majoconz's Avatar
Join Date: Jan 2008
Location: Palmerston North, New Zealand
Posts: 336
Default Re: Spectrum Comms. Active Antenna problem

You already said that you have connected all your radios to the loop and amplifier and every one was overloaded.
The Spectrum antenna has been connected to every different radios here for testing. But they all were the same = overloading, and the MW signals appearing all over, as soon as power is on the antenna.
Therefore the the only common factor is the loop and the loop amplifier. IMHO the MW band signal is cross-modulating everything in the loop amplifier - therefore a high-pass filter with a cut-off of about 1700kHz should block all the MW signals - or at least reduce them to a tolerable amount - between the loop and the amplifier is your best bet. You may need more than one filter to accomplish the required rejection.

This one for example will only block by 20dB above 1200kHz.... ZFHP-1R2-S+. You may need the next one on the list .... ZFHP-2100-S+
Lumped LC High Pass Filter, 2500 - 6800 MHz Connector Type: SMA .....but you will lose the ham top band.
Cheers - Martin ZL2MC

Last edited by majoconz; 26th Apr 2021 at 12:00 am.
majoconz is offline   Reply With Quote