[SARC] FW: [TowerTalk] Filters for Field Day

[Dave - KB4ET]

FWIW - W3LPL is Frank Donovan and he has one of the most successful Multi - 
Multi (6 bands running 1.5 KW simultaneously) Contest stations on the North 
American continent - when he talks EVERYONE else listens.. Again FWIW... 73

Dave - KB4ET

>=========================================================
>-----Original Message-----
>From: towertalk-bounces at contesting.com
>[mailto:towertalk-bounces at contesting.com] On Behalf Of
>donovanf at starpower.net
>Sent: Thursday, July 03, 2008 2:14 PM
>To: towertalk at contesting.com
>Subject: Re: [TowerTalk] Filters for Field Day
>
>Hi John,
>
>Filters are  N O T  needed to eliminate interference between multiple Field
>Day transmitters on the same band.  Antenna design, proper choice of
>polarization, physical separation between antennas, frequency management,
>and reasonably good transceivers will eliminate all interference.
>
>I was the guy responsible for designing the 18 HF antennas and the site
>layout for the 23 (yes twenty three) transmitter
>W3AO Field Day entry this year.  Fifteen of those transmitters were
>simultaneously active on the HF bands for most of the 24 hour operating
>period.  Eliminating interference among our 15 HF stations was the primary
>criteria for designing our site and the antennas.
>
>For example, on 20 meters we had four stations on the air simultaneously for
>most of the 24 hours -- with no interference at all -- on  the following
>approximate frequencies:
>   14025 CW
>   14080 RTTY or PSK
>   14175 GOTA (SSB)
>   14320 SSB
>
>So...   How did we did we eliminate all interference with so many HF
>transmitters and antennas?
>
>1. We used the full 1000 foot site diameter allowed by the rules.
>
>2. All HF antennas were horizontally polarized.  To obtain the maximum
>possible isolation between stations, no verticals or inverted V dipoles were
>used.
>
>3. All HF antennas on the same band were in a straight north-south line,
>with the largest possible separation between every antenna on the same band.
>All Yagis were pointed west, all dipoles were broadside east-west.
>
>For example -- on 20 meters -- our four Yagis were at least 300 feet from
>each other. The spacing between the SSB and GOTA (SSB) Yagis was 700 feet,
>and the spacing between the CW and RTTY Yagis was 700 feet.
>
>These concepts can be applied to a much smaller Field Day site.  To operate
>CW and SSB simultaneously on the same band, use two horizontally polarized
>antennas (dipoles or Yagis) with the elements in a straight line to minimize
>coupling.  The spacing should be as large as possible, ideally at least 200
>feet.  Use reasonably good transceivers, they don't have to be $10,000
>radios.
>
>73
>Frank
>W3LPL