[TowerTalk] 12 meters on C-4

Ron Castro ronc@sonic.net
Sat, 23 Jan 1999 18:19:35 -0800

You could be right, Ben.  I also worked the ZL9 in 12, and most of the other
Pacific DXpeditions.  What worries me is that a 5.2:1 SWR in the shack at
the end of 100' of RG-213 indicates a 15:1 SWR at the antenna, based on a
normal matched loss of 1.2 dB.  The additional losses caused by that great
of a miss-match adds another 4 dB, ending up with a gain of -5.2 dBd.

This may be mitigated by the fact that the antenna does have a 6 dB
front-to-back ratio, which would be consistent with a forward gain of 3 dB
caused by parasitic interaction with the 15 meter driven element acting as a
reflector, and/or the 10 meter elements acting like directors, making the
net loss only 1 dB compared to a dipole.  Still, it would be nice to restore
the 4 dB lost in the miss-match!

A PS to all the Tower Talk members:  I have been delighted reading the posts
on this list-server since I signed up a few weeks ago.  It's so much more
congenial and educational here then with those flame-throwin' crazies on the
regular ham radio newsgroups!

-----Original Message-----
From: Ben Bond <bbond@global2000.net>
To: Ron Castro <ronc@sonic.net>
Date: Saturday, January 23, 1999 12:47 PM
Subject: Re: [TowerTalk] Adding 12 Meters to C4

>I have a c-31xr  and worked zl9 on 12cw/ssb by using a tuner. Two other
>locals WD2K using a C-3S and KM2E using a C-4 have had the same results
>a tuner. WD2K runs 100W only.  I don't think it's worth the time or effort
>to change a already good design,
>Ben Bond W2PS
>-----Original Message-----
>From: Ron Castro <ronc@sonic.net>
>To: towertalk@contesting.com <towertalk@contesting.com>
>Date: Saturday, January 23, 1999 12:30 PM
>Subject: [TowerTalk] Adding 12 Meters to C4
>>Has anyone come up with a way to add 12 meters to a Force 12 C-4 without
>>severely impacting performance on other bands?  The SWR is quite high on
>>and even a rotatable dipole would probably work better.  I have a Force-12
>>75 meter rotatable dipole 3 ft. above the C-4, and no room below, so any
>>addition would probably have to be on the C-4 boom.
>>FAQ on WWW:               http://www.contesting.com/towertalkfaq.html
>>Submissions:              towertalk@contesting.com
>>Administrative requests:  towertalk-REQUEST@contesting.com
>>Problems:                 owner-towertalk@contesting.com
>>Search:                   http://www.contesting.com/km9p/search.htm

FAQ on WWW:               http://www.contesting.com/towertalkfaq.html
Submissions:              towertalk@contesting.com
Administrative requests:  towertalk-REQUEST@contesting.com
Problems:                 owner-towertalk@contesting.com
Search:                   http://www.contesting.com/km9p/search.htm