Vic,
Don't put a shorted strap around the choke. It will look like a shorted turn
and cause excessive current in the choke which may burn a section of the
choke out.
Somewhere I read that you should not use a continuous band around either end
to terminate the ends of the choke winding. Same thing happens.
73
Gary K4FMX
> -----Original Message-----
> From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com]
> On Behalf Of Vic K2VCO
> Sent: Wednesday, March 24, 2010 11:07 AM
> To: amps@contesting.com
> Subject: [Amps] Plate chokes (was: Re: placement of RF choke bypass
> cap.)
>
> On 3/24/2010 5:18 AM, DF3KV wrote:
> > I tried that [RF Parts] choke in one of my amplifiers without testing
> it first with the
> > GDO and it just turned into smoke on 10m.
>
> I've been working on a choke for a new amplifier project. I've noticed
> some things which
> experienced builders probably already know, but I thought would be worth
> mentioning:
>
> a) Even if the gdo has decent calibration to begin with and even if you
> are careful to use
> it properly (move it away from the choke to get the smallest perceptible
> dip) the
> frequency is pulled a lot near a resonance. I've found it necessary to
> use it together
> with a counter to get accurate, repeatable measurements.
>
> b) It makes a big difference when the choke is mounted on a chassis (and
> probably when it
> is inside a box) compared to sitting on a wooden workbench.
>
> I am trying out an idea as follows: I wrapped the choke with Teflon tape
> and made a copper
> band about 1/4" in width which I can slide up and down. The plan is to
> test the choke
> installed and wired with everything mounted and use this to fine tune it
> before applying
> power.
>
> For what it's worth my choke is 3-7/8" close wound no. 28 on a 1"
> diameter ceramic form.
> I've used the RF Parts choke before successfully, but why pay for
> something that you can
> make for nothing?
> --
> Vic, K2VCO
> Fresno CA
> http://www.qsl.net/k2vco/
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|