On 4/26/2011 12:59 AM, Jim Thomson wrote:
> Date: Mon, 25 Apr 2011 18:00:07 -0400
> From: "Roger (sub1)"<sub1@rogerhalstead.com>
> Subject: Re: [Amps] DIN vs N
>
>
>>> What's the advantage / disadvantages of the DIN ?
>> At HF, zero. An N and RG-213 will handle many times the legal limit. The DIN
>> is popular with the 20-40KW and up CB crowd and the hams running that level.
> Maybe if you don't try to cover all of 75 or 160, but I've blown out N
> connectors (Amphenols no less) running no more than the legal limit on
> 75 a number of times. I use a tuner so I can cover all of both bands and
> have not had good luck with N connectors on either of those two bands.
> On 40 I not only can use N connectors, but RG8X, and CNT240 at the legal
> limit.
>
> 73
>
> Roger (K8RI)
>
> ## here's how I got around the high swr problem on 75m. Years ago, I
> bought a new F-12, EF-180B 80m rotary dipole.
> It's 68' long, 4.8 sq foot, and has -.2db gain. [42 lbs] The 2:1 points are
> only 31 khz apart. It used alumo-weld wires for the combo linear loading+
> truss support. The stock set-up used relays and small coils..[ at the
> feedpoint] to add 8 x 62 khz segments.
>
So far I've only gone to a Fan. IE, I took a regular center fed, half
wave, sloping dipole and added a second in parallel at the feed point.
The ends are "fanned" out by 4' spreaders. There are no spreaders back
at the feed point. This almost doubled the band width, which still
isn't much. The top is about 95' while the bottom end is about 8 - 10'
off the ground. It also shifted the frequency down. I cut the antenna
to length according to formula which always comes out a little long, but
so far I've shortened the antenna about 2 1/2 feet and only moved the
resonance up to the very bottom edge of the band. Once I get the thing
on frequency then I'll short the ends across the spreader and see how
much the added capacity will lower the frequency again.
I think a third dipole would be worth while, except the size would be
getting tot he point of being a bit unwieldy whether the third dipole
would continue on in the fan or fit into a triangle shape at the end.
73
Roger (K8RI)
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