Great, now people are going to accuse others of TH7DXX-bashing... ;=)
The TH7DXX is obviously a successful product of its pre-modelling era. Lots
of people have had success with it. So this isn't bashing it, OK?
But it's surprising how many people seem to want to refuse to believe the
antennas they grew up with could have been surpassed by modern technology.
(KK9A, this comment isn't necessarily directed at you.) The thing about the
TH7DXX is, with all its aluminum, weight and windloading, it's just a
three-element antenna on 15 and 20.
(On 10m, it's a four-element.)
If you look at the manual, the maximum gain on 20 is 8.0 dBi. So take off
2.15 dB right there, and then consider the added gain for marketing
purposes, and then consider it's the maximum gain only, which would be at
the absolute sweet spot in the band.
Suddenly, it becomes a bit easier to believe it's outdone (or at least
equalled) by a smaller, computer-modelled, trapless interlaced
multi-monobander (to use an N6BTism).
Does the TH7 work? No question. Is it now the best use of aluminum? That's
up to the purchaser.
73, kelly
ve4xt
On 2/24/15 6:57 AM, "john@kk9a.com" <john@kk9a.com> wrote:
> That is surprising since the C3 has an 18' boom and uses only a portion of
> it on each band and the TH7 has a 24' boom and uses most of it. I had not
> read the K7LXC/N0AX report and did not know this. I was a guest op and the
> TH7 (with a BN-86 balun) was not my antenna. I did unscientifically
> compare it to a 4el SteppIR and saw little difference. Given the smaller
> size and lack of problematic traps, I would prefer the C3 if the
> performance was equal or better. My Aruba station had a 4el homebrew 20m
> beam on a 36' boom which seemed to work well.
>
> John KK9A
>
>
>
> To: <towertalk@contesting.com>
> Subject: [TowerTalk] Mosley Antenna Question
> From: "Jim Thomson" <jim.thom@telus.net>
> Date: Mon, 23 Feb 2015 23:34:18 -0800
>
>
> Date: Mon, 23 Feb 2015 11:23:38 -0600
> From: "john@kk9a.com" <john@kk9a.com>
> To: towertalk@contesting.com
> Subject: Re: [TowerTalk] Mosley Antenna Question
>
> The TH7 is not a bad antenna, I find it difficult to believe that a C3 out
> performs it. I had the world high 20m score in the last WPX CW using a
> Hy-Gain TH7DXX
>
> John P40A
>
> ## sadly to say, yes indeed, a C3 will outperform a TH7-DXX. K7LXC already
> ran that test.
> N6BT ran the test as well, using a spectrum analyzer at the RX end, with
> SA set
> to 2db per division.
>
>
>
> ## A C3 is like 4.1 dbd....and your TH7-DXX is less than that. The sa or
> audio gear just reads it as..
> X on ant #1..... and + /- X on ant #2.
>
> ## Compare a C3 with a Mosley TA-33jr in the above format....and the
> results
> will make u gag. Gets
> even worse when a TA-32jr is used.
>
> Jim VE7RF
>
> _______________________________________________
>
>
>
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