Hi Keith,

I do feel that length plays an important part in antenna design.  Look up
the pages written by L. B. Cebik for some good discussions of antenna theory
and design.  He makes some good points that I believe make a difference.
For example, I am currently using a doublet cut for 102 feet overall or 51
per let.  This is one of the lengths mentioned by Cebik.  I first had it at
88 feet and it was awful on 40 but worked on 80 and the warc bands well.
Then, I lengthened it to the present length.  Now, it still works well on 80
and everywhere else but is great on 40 now as well.  It seems that lengths
of 88, 102 and 132 have some special qualities surrounding them.

I hope that helps and very 73.  Good luck with your experiments.


Kevin :)
Amateur Radio:  K7RX
Navy Marine Corps MARS:  NNN0SHS




-----Original Message-----
From: Blind-Hams For blind ham radio operators
[mailto:[log in to unmask]] On Behalf Of Keith Barrett
Sent: Sunday, January 30, 2005 13:54
To: [log in to unmask]
Subject: doublet or dipoles

Hi all,

Wonder if any one has compared the doublet fed with open wire line to
dipoles cut for the required bands.

My two bands of interest are 160 and 80 metres.  I am using a doublet with a
top of around 230 feet.

I was talking to a friend today with a similar setup on 80 metres.  He went
and cut the extra ends off and made it 132 feet in length and his signal was
reported some 10 db improved.

So, I am concluding that it is possible for a doublet to be too long and the
old saying to get as much wire in the sky is not always true.

So, just wondering if anyone has made meaningful comparrisons between the
doublet and dipoles.  What about the F7FE idea of feeding more than one
dipole from the same feeder?

My activity is devided between the two bands and I do not need the aerial to
work on any other band.  I had thought of traps but I use a high power
linear and would not wish to melt them.


Keith

- -

Keith Barrett


gw4nby

Bridgend
South Wales