[CQ-Contest] W3NQN Pass Band Filters

Valeri Stefanov wally at el-soft.com
Sun Feb 9 17:21:03 EST 2003

Hi Fellow Contesters,

We are seeking for advice.
The LZ9W contest team has reached the moment when we must do something for interstation interference while operatiing M/S or M/M.
We are now going to order a set of 6 W3NQN single band 200W pass band filters.
Having in mind that all 4 operating places for mini M/M set up are located into a single room ( 4m x 6 m) and all antennas are relatively close to each other within a diameter of just app 100m we are wondering if these filters will help significantly to reduce interstation interference ?
During the last CQWW 2002 (SSB & CW) we operated without any filtering and in spite of considerable intereference we have not lost even a single front end :-))).

The 4 operating places for 2003 contest season are planned to be:

80m/10m - FT920 + Alpha 91b
20m - IC746 + ACOM 2000A
40m - TS940 + Alpha 91b
160m/15m - IC 756ProII + ACOM 2000A

Antennas are :  all WA3FET OWA yagies on 10,15 and 20m.

160m  - Inv. Vee ( app 50m away from all other antennas beside 10m ant)
80m - 2 el. phased Inv.Vees ( one element on separate Aluminum mast and second element just 3m below 20m yagi on the tower supporting 20m yagi , both 80m and 20m antennas on the roof of a three stores small hotel)
40m - HB9CV yagi on separate tower app 40m away from other antennas
20m - 6 el. WA3FET on separate tower - 40m away from 40m ant and 10m ant and 30m away from 15m ant , one of 80m ant el just 3m below it .
15m - 6 el WA3FET on separate tower abt 45 m away from 40m and 10m ant and app 30 m away from 20m ant.
10m - 7 el WA3FET on separate tower app 40m away from all other yagies and 25m away from 160m Inv.Vee . 
We also have KT34A 10m below 10m yagi on the same tower.

If anyone is interested I may send him some pictures of these antennas, but I hope my explanation is easy to understand.

So, those of you who operate in M/2 or M/M or M/S please comment on -  is it worth to buy W3NQN filters to fight the interstation QRM ? Will it be significantly reduced for these 500 USD we are going to spend ?

73's de Wally LZ2CJ(LZ8T) team member LZ9W & YM3LZ

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