Building a PL decoder out of NE567's is old-school, and I've never seen a
design that didn't have drift problems.
The MX-COM (now CML Micro) tone chips were a better way to go, but many have
been discontinued. If you can find them on the surplus market, that would
be the easiest way to go. The part numbers were MX-3x5, where x was one of
several numbers. Some were designed to be used with a DIP switch for
frequency selection, others were designed to tie to a uP and took serial
data to select the tone. Dig around for the datasheets, I'm sure they're
out there...
--- Jeff WN3A
> -----Original Message-----
> From: Repeater-Builder@yahoogroups.com
> [mailto:repeater-buil...@yahoogroups.com] On Behalf Of tracomm
> Sent: Friday, May 07, 2010 10:14 AM
> To: Repeater-Builder@yahoogroups.com
> Subject: [Repeater-Builder] Re: CTCSS Encoder/Decoder
>
>
>
> I have to agree, unless you need to Reminisce about the good
> old days when men actually built the things they used, there
> are so many inexpensive options for ctcss that actually work,
> very well.
>
> There are a few Selectone units on ebay at about $2.00 and I
> am certain members here could supply more than a few boards
> very cheaply that actually work reliably.
>
> CJD
>
>
>
> --- In Repeater-Builder@yahoogroups.com, kevin valentino
> <kevinvalent...@...> wrote:
> >
> > Grab an old Standard HX300 or C734 etc. off ebay for
> practically nothing(if you find one) the enc/dec board is a
> plug in w/wire leads, very small, dip select, and rock solid.
> I have one kickin around with the schematic if your
> interested. I have adapted these to many old crap radios and
> they always work perfectly. Just a suggestion :-)
> >
> > --- On Thu, 5/6/10, James ka2...@... wrote:
> > From: James ka2...@...
> > Subject: [Repeater-Builder] CTCSS Encoder/Decoder
> > To: Repeater-Builder@yahoogroups.com
> > Date: Thursday, May 6, 2010, 10:35 AM
>
> > Hi Guys,
> > We have been experimenting with building CTCSS Units using
> the 567 Tone Chip and good components, i.e. Caps, multi turn
> pots etc. The stability is not good in my opinion. We will
> set it to 107.2 and the next time you check it is off enough
> to where it won't decode until it is re-tuned slightly. I am
> wondering what your experiences may have been with this CTCSS
> Chip. Many articles say they work well with the addition of a
> stable voltage regulator, so we added a five volt regulator,
> no difference in stability. Any comments and experiences with
> this and other chips would be appreciated. The availability
> of CTCSS Chips seems limited.
>
>
>
>
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>
>
