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ZS6CFC > VHFUHF 08.02.06 12:09l 53 Lines 1985 Bytes #999 (0) @ WW
BID : 3C3068ZS6CFC
Read: GUEST
Subj: Re: Freq Selective propagation
Path: ON0AR<F6KMO<ON0RET<SR1BSZ<CE8FGC<ZS0MEE<ZS0DLD
Sent: 060208/1059Z @:ZS0DLD.PTA.GAU.ZAF.AF #:34349 [Pretoria] $:3C3068ZS6CFC
From: ZS6CFC@ZS0DLD.PTA.GAU.ZAF.AF
To : VHFUHF@WW
Hello
Yes , I have put a spectrum analyzer on the end of FM
antennas, and have seen some selective fading. However ,
these signals are high power and migh tell a different story
alltogether.
But , now , right here in South Africa, my location pretty
much right between Pretoria ( now :Tswane and Johannesburg)
acessing my regula' BBS in De Wild. Well, about 35+
Kilometers. No problem even wit low power. BUT annother Ham
, located so, that his way to the repeater is right over the
Airfield of Johannesburg International , reported unusual
phenomenons-probably due to heat buildup - inversions or so
- to connect to the said repeater.
And I noticed that for me , connecting up north, the signal
fades too. mostly very slowly so. I have one of the 2M "X"
Antennas , where I can select V or H Polarization. It
shifts. Maybe that is a effect observed by Andy?
I also tested a while ago connectivity to other BBss. One
gave marginal results. It worked for about just more than 15
mins , for the next 15 mins it was to low to connect-or keep
the machines talking. I observed there a plane ( meaning H /
V ) shift too. Apparently there are "heat islands/
inversions building up which facilitate this. However ,
lately I observe a change in Signal strength due to our
influx of moist air ( our rain season/ monsoon)
++ And even a change in direction of maximum signal. (Like
on long - haul - SW ) Sometimes the MAX is not due north
where it should be. (including an odd shift of plane (as far
as I can tell)
One needs here a plane steerable antenna/or fine tune
selectable- cable set for such undertakings. (The ones of
you who understand will know what I mean , the others :
blink your eyes and enjoy)
Yes , the tools for the regula' Ham are limited , but there
is still new gounds to explore.
Folow me. Or Andy for that Matter!
73 - Sten, ZS6CFC @ ZS0DLD
Message timed: 12:50 on 08 Feb 2006
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