[pskmail] Re: DK9SQ Comments

  • From: "sv1uy" <sv1uy@xxxxxxxxxxx>
  • To: pskmail@xxxxxxxxxxxxx
  • Date: Mon, 9 Apr 2007 21:25:53 +0300

On Mon, 09 Apr 2007 12:37:52 -0400, Bill - N8ET wrote
> Hi -
> I have to respond to this one even though my responsey does not have 
> much to do with PSKmail.....
> I sell the DK9SQ masts and products in the US. Several years ago 
> someone in the US claimed the mast was conductive and RF lossy.  I 
> ran some tests and was unable to duplicate the claims.  None of the 
> masts I have sold or tested have ever been conductive.  They are 
> made of fiberglass, and are an insulator.  I have tested with an ohm 
> meter and found no conductivity.  Pieces have been put in a 
> microwave oven with no heating effects observed.  I have run tests 
> on a 33' vertical wire with an antenna analyzer - first suspended 
> without the DK9SQ mast, and then moving the mast closer, and finally 
> wrapping the wire around the mast while looking for changes on the 
> analyzer at the base of the antenna.  I had to wrap the wire around 
> the mast about 6  times before I noticed any change at all in the 
> impedance at the base. The change was very minor, and I attribute it 
> to the increasing inductance in the wire as it was wound around the mast.

Hi Bill,

Thanks for info. I have read on the web (http://www.io.com/~n5fc/dk9sq.html)
that if you coil a ten meter piece of wire losely around the DK9SQ pole in
order to make a 1/2 wavelength 20 meter vertical, then received signals drop a
couple of S units, wherus if you tie the wire near the top and keep a distance
of at least a foot near the bottom of the DK9SQ pole you see received signals
go up. I have not done this myself but since you say that you have put pieces
in a microwave and tested them I believe you but this guy on the web says that
his signals dropped when he coiled his wire losely around the mast. 

I will surely make some tests myself using the DK9SQ as a vertical radiator
and report back to this group soon. I use my DK9SQ as a support for a support
for a one element QUAD and it is the best portable antenna I ever had. I also
got another DK9SQ dipole last week to use it as a mast for a small VEE shaped
telescopic dipole at about 7 meters from the bottom of the mast. It is a great
mast and I always thought it is reinforced with graphite (it is 3 times
stronger than a cheap fiberglass mast) hence it is slightly conductive. Not
sure if the manufacturer claims no conductivity, but it is nevertheless a
great and very lightweight antenna mast. I would personally recommend it to

Have you ever used it as a vertical radiator yourself and is there a
difference in received signals when you move your wire a bit further away?
I always thought this to be true so I have never tried it myself, but as I
said before this does not hinder the usefuleness of the mast since vertical
radiators are a bit noisy and not very effective unless you know a few tricks
or if you are next to the sea. 

Finally DK9SQ himself (see his web page http://www.qsl.net/dk9sq) does not
even propose using his mast as a simple vertical radiator. His antennas are
either the LOOP I have bought or dipoles.

So to conclude the DK9SQ 10 meter antenna mast is a great mast and my comments
were not meant as a bad advert or something.

73 de Demetre Valaris - SV1UY
e-mail: sv1uy@xxxxxxxxxxx
AX25 PBBS: SV1UY@xxxxxxxxxxxxxxxx

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