In addition to the below, tuning changes pretty fast
with heat rise (applied rf) and proximity to other
metals.
skipp
> Eric Lemmon <[EMAIL PROTECTED]> wrote:
> Tom,
>
> If you have been following this thread for a while, you probably have
> picked up on the fact that the typical isolator cannot be tuned more
> than 1 or 2 MHz away from the original factory tuning. It takes more
> than a spectrum analyzer to properly tune a circulator or isolator.
> Moreover, the typical isolator/circulator must be remanufactured in
> order to work properly on a frequency that is more than 2 or 3 MHz away
> from the original frequency.
>
> Although the best action is to return the isolator to the factory for
> rework, some firms, such as EMR and Telewave, have the expertise and
> wherewithal to remanufacture isolators made by others. Judging from the
> postings on this subject, I think that some readers may believe that an
> isolator may be retuned to the 2m band from the 160 MHz band simply by
> tweaking a few variable capacitors. Not true! Several internal
> components may need to be replaced, reground, or remachined in order to
> fit the precise parameters needed by a new operating frequency.
>
> 73, Eric Lemmon WB6FLY
>
> Thomas Oliver wrote:
>
> > After losing a PA I am wanting to put an isolator in line before
> > installing the new amp and was needing some information about an
> > isolator I have, it is a Microwave Associates model # J-2101multi
> > stage isolator origionaly on 460 Mhz. Does anyone know if it can be
> > retuned down to 442 Mhz? or any othe specifications of this beast? I
> > have tried to remove the outer cover and it seems to be held with
> > something other than the 4 cover screws. tom n8ies
> >
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