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Old August 28th 07, 11:36 PM posted to rec.radio.amateur.antenna
Owen Duffy Owen Duffy is offline
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First recorded activity by RadioBanter: Dec 2006
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Default How to make a Stationmaster for hf ?

Wimpie wrote in news:1188313351.276557.292100@
22g2000hsm.googlegroups.com:

clipped... a nice description of an end fed vertical half wave with
matching network.

Wimpie, I think the OP had using the stationmaster radiator element
unchanged on lower HF bands.

You could view this as a 5.5m long radiator sitting on say, a 4m metallic
support mast, fed at the junction of the two. Typically the configuration
involves no radials at the base of the 5.5m radiator, and an shabby
connection to earth at the base of the supporting mast.

If at 80m you were to assume the earth resistance was as good as 30 ohms,
the earth loss alone would account for 60% of the power reaching the
feedpoint when the antenna is modelled without provision for current on
the outer of the feedline.

So, the StationMaster as described in the article is typically a ground
mounted ~1/8wl vertical with an inadequate ground system, elevated feed,
high sensitivity to noise, highly susceptible to RF in the shack unless
the feedline is decoupled adequately.

It is a little better on 40m, but all of the issues remain.

A lot of the guys wanting to do such a thing are our new six hour hams,
and they would be principally interested in 80 and 40m.

Owen