n4kg@juno.com (T. A. Russell): Re: Rotatable Dipole

[T. A. Russell]

--------- Begin forwarded message ----------
From: n4kg@juno.com (T. A. Russell)
To: k0wa@southwind.net, N4KG@juno.com
Subject: Re: Rotatable Dipole
Date: Fri, 31 Jan 1997 17:09:15 EST
Message-ID: <19970131.160944.4670.3.N4KG@juno.com>
References: <1.5.4.32.19970131175847.006cf6a8@southwind.net>

Lee -

The answer to your question about 40M rotary dipoles is:

KLM - if you like linear loading and lots of tiny little parts and
enjoyed 	
          playing with erector sets as a child...

Hy-Gain - if you like linear loading and plastic insulators

Force 12 - if you like linear loading and big wire loops

Mosley - if you like big coils and center  loading (which is less
efficient IMHO)

Cushcraft - if you like simple effective solutions...It's a good idea to
double wall the first piece of tubing out to the first joint on each
side...raises safe wind speed from 73 mph to over 90 mph by my
calculations.

Gamma match the boom of any 24 ft tri-bander or 3L20 as a rotary dipole
on 	40M (and 30M as well)...actually, it's easier to use an Omega
match...if you like to tinker on the tower.

I have a beefed up Cushcraft 2L40 at 95 ft which performs most
satisfactorially.  It is very competitive on CW where it is tuned and
works OK but not as well on SSB.  It withstood 80-90 mph winds that took
down 30 some trees on my 4 acres, including a couple of 75 year old Oaks.
 (I have no association with Cushcraft other than as a satisfied
customer.)

I have omega matched a Telrex 3L20 boom as a rotary dipole on 40M and a
TH6 boom as a rotary dipole on 40 and 30M.  A 24 ft boom with 20M
elements endloading it is self resonant around 7.5 MHz.  

BTW, before I ever had any gain antennas on 40M, I worked over 300
countries with rotary dipoles at 80 ft.  They are very effective!

73, Tom - N4KG
:
--------- End forwarded message ----------

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