Agreed it runs into trouble with spacings less than .5 wavelength.
However, I have found that performance in the real world seems to be on the
money
for spacings greater than .5.
Bill K4XS
In a message dated 2/21/2015 12:40:49 A.M. Coordinated Universal Tim,
xdavid@cis-broadband.com writes:
HFTA is a poor judge of spacing. There is a known flaw in the model,
and it will overstate the stacked gain for narrow spacings.
73,
Dave AB7E
On 2/20/2015 1:56 PM, Pete Smith N4ZR wrote:
> Assuming you meant a second C-3, I did extensive modeling of pairs of
> C-3s back in the late 90's when I put my stack up. There was an NCJ
> article, but if you like I can try to dig up the manuscript here.
>
> I wound up with C-3Es at 97 and 69 feet. It's too wide for the best
> 10m pattern and not wide enough for optimum on 20, but it worked out
> to be the best overall compromise. I would have put up a third
> antenna at around 35 feet, but the tower would have been marginal.
>
> Your case will depend on local terrain, and on take-off angle data for
> your part of the country. HFTA modeling will give you figures of merit
> for various paths that you can use to reach the best compromise, given
> your location and, perhaps, the prospects for 10M in the next cycle.
>
> 73, Pete N4ZR
> Check out the Reverse Beacon Network at
> http://reversebeacon.net,
> blog at reversebeacon.blogspot.com.
> For spots, please go to your favorite
> ARC V6 or VE7CC DX cluster node.
>
> On 2/20/2015 3:36 PM, Keith Dutson wrote:
>> I have a F-12 C3 up at 120 feet. I want to add a second C-2. What
>> would
>> you recommend for spacing? QTH is Houston, TX area. Thanks.
>>
>>
>> 73, Keith NM5G
>>
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