Dave Sergeant wrote:
>From Dave G3YMC
Six months or so ago I regular copied IK5ZPV (and I5MXX) at 579. Lately his
signal has been much down, 549. Is this change in propogation or has there
been a change at his station?
I5MXX heard 569 Wednesday evening.
73s Dave
[email protected]
http://ourworld.compuserve.com/homepages/sergeantd
Hello to all,
Thank for your report Dave,yes, i modified my antenna configuration after a wind
storm crashed the poles i used. (26/12/1999)
Now i have an asymmetrical T antenna, composed of a single horizontal wire about
100 mt long and 13 mt high.
This antenna is simpler than older one, shaped like an horizontal V with one arm
composed of only one wire abt 60 mt long, the other by 4 wire spaced 1 mt and
abt 33 mt long (the mean high of wires is the same).
The capacitance now is almost the same then before, so i use the same inductance
to tune.
The resistance at resonance is lower and i have more current in antenna with
the same input power and in the MOS-FET, so i cannot use the TX at full power so
i use about 800 w rather than 1.200 w.
Now the horizontal wire for about 50% of his length run over an olive-grove with
trees 4/5 mt high.
May be this is the most important difference, so in the future i will try to
shunt the trees using radials insulated from ground.
Since last modifications at antenna i had several QSO with station i worked in
the past and reports seem on average almost the same i received.
Also some new field strength measurements made by I5TGC, I5MXX and IK5BQL (about
30 km apart from me) are the same that in the past.
I have some discordant reports, may be because propagation conditions are
variable, may be because antenna performance are different, so further reports
and suggestions are welcome.
I know that also I5MXX made radical mods to his antenna after the storm, but i'm
not able to say if are important variation in performance
'73, Valerio (IK5ZPV)
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