--- On Wed, 6/4/08, Willis M. Hagler <[EMAIL PROTECTED]> wrote:
> From: Willis M. Hagler <[EMAIL PROTECTED]>
> Subject: [Repeater-Builder] Re: 455khz filter for Mastr II discriminator audio
> To: [email protected]
> Date: Wednesday, June 4, 2008, 5:54 PM
> Whoa, where did we get off on voters?
>
> I asked the question originally based on a conversation I
> had with
> Pacific Research. I'm using their RI-300e controller
> which has been a
> solid controller for me on several other repeaters, but
> I've never
> tried to interface to a Mastr II. With the particular
> combination of
> a Mastr II and the RI-300e "smart squelch" setup
> I find the squelch
> action is not working well at all.
>
> I spoke with Greg (Gregg?) on the phone and he said they
> have had
> trouble with 455khz coming out of the receiver and throwing
> off the
> "smart squelch". Their manual also mentions
> this:
>
> http://www.pacres.com/support/manuals/ri-300%20user%20manual%20v3_11.pdf
>
> On printed page 12 (pdf page 20) it says
>
> If your discriminator does not
> have adequate filtering for 455 kHz, you will have to
> provide for this
> filtering between the radio and controller. A 10mH
> inductor in line with a 1000pF capacitor to ground should
> work. You
> may need to adjust these values according to the output
> impedance of your discriminator.
>
> So I was proceeding down the path of a 10 mH inductor, and
> the
> feedback I really wanted from this group is what to do
> about this
> inductor as I see I can buy either a through-the-hole board
> mounted
> one that appears to look somewhat like a capacitor, or I
> can get a
> bunch of windings on a torroid core and make a choke.
> I'm pretty new
> at this so was asking more for advice along these lines.
>
> However, it's also very useful to know that the GE
> Mastr II UHF
> receiver shouldn't be outputting 455khz at all so
> I'm still not sure
> what the problem is.
>
> Thanks all,
> Mark Hagler
>
> W7WMH Seattle
>
>
As the Mastr ll does not have an output of 455 but around 9 to 11 MHz that
should be a non issue. There is an inductor and capacitor to ground that
should eliminate any rf comming out of the volume/squelch high pin that I
assume that you are using.
