[FoxHunt] HTX-202 Audio S-Meter Mod

Thu, 6 Jun 2002 16:51:12 -0400

How do you bring out the S-meter voltage?  Did you use an existing
connector, add one or what?  What signal processing did you use between the
tap off point and the polar plotter?  Marv said he didn't see any details on
your web site.

Thanks, Jess, w4pqk

-----Original Message-----
From: R. Simmons <[email protected]>
To: [email protected] <[email protected]>
Date: Thursday, June 06, 2002 4:06 PM
Subject: Re: [FoxHunt] HTX-202 Audio S-Meter Mod

>Quite right, I use the signal on pin 13 of the MC3372 chip... the pdf data
>sheet shows a graph of the signal on this pin vs RF input signal.
>
> As Marv says, I use it to drive a feedback loop in a polar plot display DF
>:
>
>www.silcom.com/~pelican2
>
>And it works nicely...
>
>----- Original Message -----
>From: "Jess Hancock" <[email protected]>
>To: <[email protected]>
>Sent: Thursday, June 06, 2002 9:41 AM
>Subject: Re: [FoxHunt] HTX-202 Audio S-Meter Mod
>
>
>> IC4 is a Motorola mc3372 IF strip.  Check the link:
>>
>> http://pubpages.unh.edu/~aperkins/pdf/mc3372.pdf
>>
>> Pin 13 is labeled Meter Drive and in one of the diagrams is labeled RSSI
>> Output which I believe is the S-Meter output of the chip.  In the HT
>> schematic this is connected back to pin 10, Filter Input.  Filter output,
>> pin 11 appears to be DC coupled and drives a line labeled SGL.  The
>junction
>> of R33 and R34 might be a possible S-meter dc voltage pickoff point.
>>
>> Let me know.
>>
>> 73, Jess, w4pqk
>>
>>
>> -----Original Message-----
>> From: Marvin Johnston <[email protected]>
>> To: [email protected] <[email protected]>
>> Date: Thursday, June 06, 2002 11:34 AM
>> Subject: Re: [FoxHunt] HTX-202 Audio S-Meter Mod
>>
>>
>> >
>> >Bob Simmons, WB6EYV, taps into the HTX-202 S meter circuit to use the
>> >HTX-202 with his Yagi Plot setup. I checked his website
>> >(http://www.silcom.com/~pelican2/) but didn't see any mention of the
>> >mods. He does read this list, and can probably answer the question.
>> >
>> >Marvin, KE6HTS
>> >
>> >Dennis Boone wrote:
>> >>
>> >> As an electronic technician, I'm not a bad computer sysadmin, but I
>> >> went looking for such a point a few years ago for exactly the same
>> >> reason.  My fuzzy memory seems to recall that the only place s-meter
>> >> intelligence was available outside of an IC was in a form suitable for
>> >> driving a display, e.g. bcd, serial, or some such.  I'd love to be
>> >> proven incompetent on this one, though.
>> >>
>> >> Dennis Boone
>> >> KB8ZQZ
>> >>
>> >>  > I know a ham that claims to have done most of the factory service
>work
>> >>  > on the 202 for RS.  I posed the same question him a few years ago
>and
>> he
>> >>  > could not come up with a point.  He seemed to be sincere  but you
>> never
>> >>  > know.  The tight front end would make it a great fox hunting rig.
>> >>  > Please post the information if you find a mod.
>> >>
>> >>  >  > Has anyone ever tried to find a point on the Radio Shack
>> >>  >  > HTX-202 HT PCB to tap off the voltage/signal from the
>> >>  >  > S-meter display circuit chain?  I'd like to see if I can add
>> >>  >  > a voltage driven osc for a audio S-meter to a -202.
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