[Lowfer] Fades - reasonant high tower light gantries?

[Michael Sapp]

Laurence & All:  Down here in 3 land W9UK made a good living de-tuning cell 
towers for the lower 48 AM BC market after retiring from the local clear 
channel station as chief engineer.....plenty of those towers are in the same 
general height range....(130 to +300 ft). They can really mess an AM BC 
antenna pattern up acting as a parasitic element in addition to the 1/4 ~ 
1/2 wave shadowing effect you noticed....

Mike wa3tts


----- Original Message ----- 
From: "Laurence KL7 L" <hellozerohellozero at hotmail.com>
To: <lowfer at mailman.qth.net>
Sent: Tuesday, October 15, 2013 4:37 PM
Subject: [Lowfer] Fades - reasonant high tower light gantries?


> Slightly more MF but I was driving to work this morning (about 1100 local) 
> and monitoring my new local 1Kw stataion KWAP 1430kHz here/there  in 
> Wasilla  (Sarah Palin land) - I was on the Glen highway about 30 miles 
> over the inlet away from the station listening to the s/n when sporadially 
> the signal faded out just about completely - Im guessing I had about 20dB 
> s/n as I was still listening to "music with noise".
>
> Looking around I saw a number of offset large high HPS about 150ft tall 
> "top loaded" lighting  masts covering a numbering of intersection and sure 
> enough it appeared that the fades occured in line and behind the masts at 
> probably 1/2 and 1/4 wave points - this is conjecture but youll get the 
> idea.  Ive just not noticed it before and it does appear a broad resonance 
> type event as driving "in front" and a couple of hundred feet away the 
> signal was actaully broadly enhanced a few dbs - enough for me to say so. 
> Ill have another go tomorrow. Is this common in the broadcast world -? The 
> calcs look like the masts may be around 1/4 wave or so at 1430kHz.,..
>
> Laurence KL 7 L
>
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