[Top] [All Lists]

Topband: 4sq receive antenna side filters?

Subject: Topband: 4sq receive antenna side filters?
From: Grant Saviers <>
Date: Mon, 11 Sep 2017 07:25:55 -0700
List-post: <>
I was asked by a DXpedition leader if it was practical to bandpass filter the input (antenna side) of the DX Engineering 4 sq's they plan to use (I have one). Given the few acres of the island and 5 feet ASL there isn't space to get adequate antenna separation and of course both transmit antennas are verticals. The concern is with QRO transmitters on 160 and one on 80m at the same time that the coupling will cause overload and IM. Beverages would not work above the salt water intrusion. A direction switchable DHDL is planned for 40m.

Any thoughts on if this is possible, been done before, or how to do it?

A deeper question is what impedances are possible for a 20' whip and the input of the amplifier for a filter design? Sacrificing noise performance, some gain, and frequency range are all reasonable to solve the problem. Probably more than 40db of rejection is needed. Switching a pair of filters with an outboard box on each whip looks to be the easy part.

Grant KZ1W
Topband Reflector Archives -

<Prev in Thread] Current Thread [Next in Thread>