N9NEO wrote:
Is anyone here interested in collaborating on a small pc board with a
precision detector and an elliptic filter? and maybe even a small
amplifier too. This would be a retrofit to existing radio. I have
heard it is almost as good as a sync detector- better than some. I
have heard others say it is smoke and mirrors so I expect to get to the
truth here.

I am looking for two other people to help out. Board will cost you
maybe 30 bucks. I use PCB express. You get three small boards no silk
no solder mask for about 60bucks. I am in-between consulting jobs now,
so that I have a little time but watching my funds. I think with smd
parts maybe only half a board is needed so that each will cost even
less.


Idea has been around for quite some time but recently brought to my
attention by Terry. I am looking at that Redsun RP2100 unit as the
platform to run with.

regards,
NEO


I have more then enough proejcts to keep me busy until
the cows come home to even think about getting into a
collaborative project.

Right now I am concentrating on Dallas Lankfords active
antennas and his simple but extremely effective phaser".
It is near magic to turn a pot and steer your recptin pattern
from ~100KHz to at least 27MHz. I haven't found anything
in the 28~35MHz range to test yet.

This is the best single detector I have found.
There is another fitler on this web page, but it requires matched
diodes and after extensive listening tests with a test group of
two,my wife and I, is not as "smooth" or sounds gritty.
http://www.amwindow.org/tech/htm/alowdisdet.htm

A very usefull single "knob" tone control. I can't make up my mind
if a wider range single unit is better the two filters, one for male
and the other for female voices. I keep flipping my postion on this.
Right now I have one wider range control. But I suspect I will go
back to two. My wife insists I ought to just go with three,
a wider and two narrow fitlers.
http://members.tripod.com/roymal/ReverbTone.htm

And this is a very usefull audio fitler for radio with less then ideal
IF filters. I have built several units based on this design for
friends.

http://www.geocities.com/rbrucecarter/amaudio.htm

Don't ignore the AF power amp. A good clean amplifier here is
a must. I will dig out the specs and a sourc for the bridge mode
power MOSFET output IC I now use.

Be usre to check out Tom Holden's very good "Synch_AM "
Sync AM Demodulators Yahoo Group at
http://groups.yahoo.com/group/Synch_AM/.
There is a lot of good data in the message section and the
files section contains a lot of good information.

One guy, Jara Rat, has some very simple and thoughtful ideas.
While I went with the AD607, there are other very good synch detectors
that may well work better in the wild and wooly world of HF/SW.

Having lived with a R8B for a few months, I must admit the SAM in the
R8B is significantly "better" then the AD607. Sadly the R8B does not
have a 455KHZ IF making it difficult to use my exsiting outboard
multimode detector. I am going to avoid trying to define "better" as it
gets too subjective. If I can't measure it on a meter or scope, or at
least demonstrate it with statatistics, I just can't in good faith try
to
offer a difinition. With my original studies on SAM, IF filters, and
the audio
chainI still feel like I am pushing audio snake oil. In spite of a
year+ series
of tests with my now fried "Far Field" voice mirror beacon, it just
feels wrong
that simple audio stage differences could make a 6dB difference in
signal
levels that I could copy. Since I no longer have that beacon, and since
I
never could duplicate the effects of ionspheric "disturbances" I was
never
able to really evaluate the advantages of the various types SAM over
one
another.

I have built a mixer to convert the R8Bs final IF back up to 455, but
that
project is on the shelf for a while.

Terry