I've disassembled and compared the ham-split PD633-6A-1N and regular 450-470
PD633-6A-2N. The resonators are identical; they're the same length. The
difference is where they are tapped - the low-split model is tapped about
1/4" further up the resonator than the 460 MHz version. The semi-rigid
interconnect cables are slightly longer on the low-split model as you might
expect. I took pictures and started writing it up as an article but never
finished...
--- Jeff WN3A
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]] On Behalf Of Joe
> Sent: Saturday, February 06, 2010 9:45 PM
> To: [email protected]
> Subject: Re: [Repeater-Builder] RFS TDE-7780A
>
>
>
> I wonder what they do to the internal coupling at the factory
> when they
> tune them. Maybe it is something that can be done in the field with a
> little surgery?
>
> Joe
>
> Eric Lemmon wrote:
> > Point taken. One factor that will directly affect how the
> subject duplexer
> > will perform at 70cm is where the original factory tuning
> was. For example,
> > if the factory tuning was in the 450-455 MHz band, such a
> duplexer will
> > likely perform better at 70cm than will a duplexer that
> originally was
> > factory-tuned for the 460-465 MHz band. The results I
> quoted were for a
> > duplexer in the latter class.
> >
> > 73, Eric Lemmon WB6FLY
> >
> >
> > -----Original Message-----
> > From: [email protected]
> <mailto:Repeater-Builder%40yahoogroups.com>
> > [mailto:[email protected]
> <mailto:Repeater-Builder%40yahoogroups.com> ] On Behalf Of Joe
> > Sent: Saturday, February 06, 2010 2:59 PM
> > To: [email protected]
> <mailto:Repeater-Builder%40yahoogroups.com>
> > Subject: Re: [Repeater-Builder] RFS TDE-7780A
> >
> >
> >
> > Correct, but if I remember you were claiming 3dB loss at the pass
> > frequencies. I was seeing about 1.5dB loss. I claimed respectable
> > results, not perfect results. I think it is still
> acceptable for ham
> > use. Everything is a compromise when you push the equipment
> past its
> > limits, but the typical ham is frugal (aka me) and accepts a little
> > degradation for economy.
> >
> > 73, Joe, K1ike
> > Another parsimonious Yankee ham.
> >
> > 73, Joe, K1ike
> >
> >
>
>
>
>
>
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