10.7 IF/Detector
 

On 28 Jan 2015 22:25:03 GMT, Rob wrote:

nothermark wrote:
I need a simple poor ham's deviation meter. That got me looking at
the IC-7100 receiver sitting in my shack. I could get to the
discriminators but it would be a bit messy.

I assume you mean the IC-R7100, not the IC-7100 which is a completely
different thing.

I have an IC-R7100 and I added a 9-pin DB connector and put the direct
detector outputs on it for different purposes. It was not that difficult,
if I remember well.

blasted bifocals! I missed the R.

10.7 IF/Detector
 

On 29 Jan 2015 08:39:13 GMT, Rob wrote:

nothermark wrote:
On Wed, 28 Jan 2015 18:17:08 -0500, "Ralph Mowery"
wrote:


"nothermark" wrote in message
...
I need a simple poor ham's deviation meter. That got me looking at
the IC-7100 receiver sitting in my shack. I could get to the
discriminators but it would be a bit messy. OTOH it has a 10.7 MHz IF
output I could add an amplifier and detector to and feed that to my
O'scope to do what I want for long enough to sort out some problems.
That got me looking for a simple detector circuit. No joy so far. I
would really appreciate any pointers to either a circuit I could
breadboard or a canned solution. I was thinking I'd go commercial and
add some gain for a better look the narrow bandwidths used in
communications gear but anything that will work with normal HT's will
solve my problem. Thanks for any help!

If just for a short time, just hook the scope to any audio point before the
voulme control. There may be a monitor output already that you can use.
You can then calibrate the devisions on the scope against a known source.
While not real good and varies with the frequency of the audio source, just
hook the scope across the speaker or plug in an external speaker. Youjust
have to set the volume at one point and not change it from the calibration
point you use.

If you can find an old scanner that has a true descriminator output instead
of the phase detector types, then it is easy. Hook a DC scope to that point
and fine a transmitter that has 1 khz steps . Go up and down one 1 khz at a
time and see where the trace goes. At each point will be the 1 khz steps.

Hmmm, had not thought about that as I am also looking for a deal on a
signal generator. Come to think of it a 1 KHz shift between the
receiver and a transmitter will look like 1 Khz of deviation....

Of course in these days you can use an RTL2830 DVB-T stick as a measurement
device (with some software like SDR#)

For $10 you will have a spectrum analyzer, measurement receiver and
deviation meter, without using your receiver or scope.

I did not know that. Do you have a link to where to start?

10.7 IF/Detector
 

"nothermark" wrote in message Of course in these
days you can use an RTL2830 DVB-T stick as a measurement
device (with some software like SDR#)

For $10 you will have a spectrum analyzer, measurement receiver and
deviation meter, without using your receiver or scope.

I did not know that. Do you have a link to where to start?



I don't know if they can be used for deviation checking,but they do work
sort of as a spectrum analizer and make a very good broad range receiver
from about 25 MHz To 2 Ghz depending on the model. Either the 820 or the
4000 modles are the ones to look for. The 820 starts about 25 mhz and goes
to 1.5 ghz. The 4000 starts around 55 mhz and goes to about 2 Ghz.
They are made for the Europen TV stations,but it was found out that with the
right software they will receive AM,FM, SSB. I have both units and the
sensitivity is around .5 uV for a full quieting signal. Not great, but not
bad for the price.

Looks for some software called SDSHARP or it might be called SD#. That is
one of the easy ones to get started with. Don't expect to hear much with
the antenna that comes with them, but with a Discone antenna up about 20
feet I hear lots of stations all over the bands.

They come with a disc for th eEuropean TV stations, but do not load or use
that.
You may need an antenna connector adaptor for them.

YOu can start here

http://www.rtl-sdr.com/tag/sdrsharp/

Just order them off ebay direct form China and get them in about 2 to 3
weeks.

Look on ebay for some of the dongles such as this for around $ 10 to $ 20.
400585241203