[RFI] DFing intermittent connection

Gary Johnson gwj at wb9jps.com
Sun Aug 8 17:41:21 EDT 2021


Bonding of the mast to the tower has been mentioned in the past. Thrust bearings and rotators are not necessarily great electrical commutators. Since those connections are near the most intense RF field, it's a great place to do nonlinear mixing etc.

73,
Gary NA6O

> 
> I am a serious contester, and do lots of SO2R. That means I need to be able
> to listen on one band while transmitting on another band. With filters and
> stubs I have brought the harmonic and overload energy down to acceptable
> levels. However, I have recently developed a new problem. Something on the
> tower is intermittent and causing the level of the 2nd harmonic to vary
> many S-units as the wind blows or I turn the rotator on the 40 meter beam.
> When this happens it creates hash across the band. I have looked for the
> obvious, but no luck yet. Yes, it could be something loose on the 40 meter
> beam hardware, but before I take on the project of taking it down, I would
> like to pinpoint the source. I am a tower climber, so I can get close to
> everything on the tower. What are the options for something handheld, very
> directional, and not overloaded by the fundamental ?
> 
> 73,
> Steve, N2IC




More information about the RFI mailing list