Hi Grant -
I believe that your TH-7 is a tribander with a dual driven element to give
broader band coverage. The TH-11 definitely has an LP cell that covers all
of 10m-20m, plus reflectors and directors, with some traps, which are not
within the driven LP cell. The TH-11 has slightly less gain than the TH-6
and TH-7, but does cover the WARC bands, with only a little more weight,
wind load, and turning radius than the TH-7. Mechanically most of the
hardware is in common with the "Thunderbirds".
Gene / W2LU
----- Original Message -----
From: "Grant Saviers" <grants2@pacbell.net>
To: "Mike Newman" <mnewman@clear.net.nz>
Cc: <towertalk@contesting.com>
Sent: Friday, March 30, 2012 12:15 AM
Subject: Re: [TowerTalk] Hy- Gain Thunderbird
> I've owned three TH7DXs, first one in 1978. #1 & #2 were made by
> HyGain, it's now made by MFJ. I think that before that Telrex made them
> and as far as I can tell they are mechanically identical. I think there
> may have been some tweaks to the feed balun, but am not sure. I now
> have a brand new Telrex made model I picked up at an estate sale, but
> mice ate the original shipping boxes (NINB - new in no box?). I don't
> think it is fair to characterize it as log periodic, since the directors
> and reflectors are trap tuned (or unique) to each band. It does have
> two driven elements for broader bandwidth. My first two survived
> several Massachusetts hurricanes and worked well.
>
> Grant KZ1W
>
> On 3/29/2012 5:54 PM, Mike Newman wrote:
>> Hi all
>>
>> Looks like there are a few models called Thunderbird.
>>
>> The one I'm enquiring about has a diagram entitled
>>
>> TH11DX 5 band (14 - 30 MHz) Super Thunderbird Yagi Antenna.
>>
>> It has 11 elements. It's probably a log-periodic in part with other
>> elements interleaved, all on a 24 ft long boom.
>>
>> An operator here has one, and we are using it as an example in an
>> planning dispute.
>>
>> Can any one on this list tell me approximately when this antenna was
>> first marketed, and whether the design has changed over the years?
>>
>> 73 de miken, zl1bnb
>> _______________________________________________
>>
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