C3 VS TH7

[Ron Stone]

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| Ron Stone, GW3YDX -    EMail ron at gw3ydx.demon.co.uk                 
                               
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I've been asked by a couple of guys to detail my experience ref the C3 
/ TH7 tests I did. 

I had the TH7 (had it for about 3 years now) on a 85 ft tower. I also 
had a UK make trap tribander - essentially a TH3 clone - at 95 ft on 
another tower. This TH3 clone was always notably inferior to the TH7. 
About 4 dB worse on 20m and maybe 6 dB on the other bands. This 
judgement was made by having those antennas in situ for a couple of 
years. For info there is a 204-CD 10ft higher at 105 ft. 

I became interested in Force 12 mainly because of some comments Dave 
Lawley, G4BUO made about them (so Dave - this is all your fault). 

To cut a long story short I decided to start up a business importing 
Force 12 amongst other antennas and shipped in a small consigment of 
Force 12 products including a C-3. I wanted to try them before putting 
them on the UK market. 

Initially I put the C3 up on a 60 ft crank up and compared the 3 
antennas. The C3 seemed to be pretty good but it wasnt really fair to 
attempt conclusions with such a significant difference in height. So I 
took down the TH3 clone and put up the C-3, at 95 ft, in its place. 
There was no way even with that slight height difference of 10 ft that 
it would outshoot the mighty contest proven TH7..... so I thought....

Well, it did. Over long hauls such as to VK long path, to JA and to W6 
it was always as good as and never worse than the TH7. These 
conclusions are just for 20m, 15 and 10 being permanently in the 
doldrums - the C-3 may well work like a dog on those bands - but I was 
deeply impressed with 20m. 

Now there MIGHT be some site superiority on the 95 ft tower. But I 
don't think so - it would have showed up with the TH3 clone which then 
SHOULD have been better than the TH7, particular as 10 ft higher. The 
inescapable conclusion has to be that, at the same height, the C-3  
would at least equal a TH7 on gain on 20 and outshoot TH3 class 
antennas on 20m every time. The TH3 clone by the way has a 18 foot 
boom and is a known good tribander.

I was very pleased with the C-3 tests and the next step was to offer 
the antenna for review in the UK magazine "Ham Radio Today". The 
reviewer (local to me) took down his Cushcraft A3S temporarily, and 
was so delighted with the C3 that he  bought it. The A3S still is in 
his garage 3 months downstream. I've not sold many C-3's - the UK 
market being pretty small for beams - but those that have bought them 
are delighted. There is even a guy that changed from a 3 el monobander 
on 15 to a C-3 and thinks the C-3 is better. I'm not at all sure about 
this - having no data on the monobander. I'm just reporting what a 
customer has said. 

In my view the only tribander that may challenge the C3 is the KT34 
series from KLM. I now have a KT34XA up and although not up at the 
same time as the C-3, the XA outshoots the TH3 clone (now again on the 
95 ft tower) by a wider margin that used to be the case with the TH7.
There are however mechanical considerations with the KLM that may lead 
it not to be my choice in a stack. I may still go for stacked TH7's in 
a stack as although the C-3 is a great gain antenna it has the front 
to back of a 2 el yagi - as expected. 

Anyone who  has contested from Europe knows that QRM rejection is 
pretty important so the TH7 may well still come out on top !

If anyone would like more details of these tests or would like to 
challenge the methodology please go ahead. 

73
Ron


>From mats.persson at mbox2.swipnet.se (Mats Persson)  Thu Aug  3 23:28:56 1995
From: mats.persson at mbox2.swipnet.se (Mats Persson) (Mats Persson)
Date: Fri, 4 Aug 1995 00:28:56 +0200
Subject: Contestlogger called NA/EU still exists?
Message-ID: <199508032228.AAA22684 at mailbox.swip.net>

Hi,

Does anyone know if this program still exist? We used EU2.0 or something in 
the SAC contest last year but it was an old not very reliable version but 
the program we used. We would like to get an updated version for the SAC 
contest that can handle a MULTI/MULTI Effort in that contest. For some 
reason the old version could not handle multiple computers on line like CT 
but I think it was based on the same code. Any information is welcome about 
this program or any other that we might be able to use. Any program to be 
interesting must have the capability to be networked.

73 de Mats SM7PKK    for SK7CE Contest Team