RS PRO 197 way off frequency?

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AD5KO

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I have a new RS PRO 197, I was scanning the 2 meter ham band and came across people using 10 codes and no call signs on 145.030 FM. So I tuned my portable ham radio to that frequency, both radios are using factory antennas attached directly to the radios.

My ham radio, a yaesu portable picks up nothing at all on 145.030 but the 197 picks up these signal with 5 S units (max). It even gives the CT tone on the display and the audio is excellent.

So, I am assuming the 197 is off frequency?

Thanks for any help.
 

gewecke

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I have a new RS PRO 197, I was scanning the 2 meter ham band and came across people using 10 codes and no call signs on 145.030 FM. So I tuned my portable ham radio to that frequency, both radios are using factory antennas attached directly to the radios.

My ham radio, a yaesu portable picks up nothing at all on 145.030 but the 197 picks up these signal with 5 S units (max). It even gives the CT tone on the display and the audio is excellent.

So, I am assuming the 197 is off frequency?

Thanks for any help.

You are receiving an image. the pro-197 is VERY prone to strong signal overload.
Try turning on your attenuator (ATT).

73,
n9zas
 

K9WG

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N9ZAS is correct. Assuming that the PRO-197 uses a 10.7 MHz i.f. - 145.030 + 10.7 (i.f. frequency) = 155.73 - I bet if you tuned your ham radio to 155.73 +/- you would hear the same comms.
 

AD5KO

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Thanks for the replies.

Yes the local sheriffs department is on 155.730, I will try the attenuator but I'm not sure it will make any difference. Really I expected more from a $300 scanner, I had a Uniden scanner that didn't do this but it didn't do digital either.

73,

AD5KO
 

K9WG

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The problem with scanners vs a transceiver is the need for a wide band front end. Anytime you have that much receive bandwidth you invite images. Just the nature of the beast.
 

DonS

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I don't recall the the pro-197 or 106 being advertised as a triple conversion receiver? :roll:
It's described that way in the user's guide:
The PRO-106 User's Guide said:
Receiver System
Triple conversion PLL super-heterodyne
1st IF.............................................................. 380.8 MHz
(The 1st LO uses high side of receive frequency
range for VHF and UHF Low/T, and low side of
receive frequency range for >512 MHz)
2nd IF .............................................................. 21.4 MHz
The second LO uses low side of 1st IF)
3rd IF ..................................................................455 kHz
(The 3rd LO uses the low side of the 2nd IF)
 

KE4RWS

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Pro-197 / PSR-600 Triple Conversion Receiver

I don't recall the the pro-197 or 106 being advertised as a triple conversion receiver? :roll:

73,
n9zas
According to page 86 of the Pro-197 manual it is, not to mention a simple internet search of it's receiver specs :roll:
 

gewecke

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Huh, I guess I never caught that when I bought it. All this time I thought it was a double conversion scheme,lol!
Does this apply to the 106 as well?

Thanks guys! :)

73,
n9zas
 

DickH

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Thanks for the replies.

Yes the local sheriffs department is on 155.730, I will try the attenuator but I'm not sure it will make any difference. Really I expected more from a $300 scanner, I had a Uniden scanner that didn't do this but it didn't do digital either. ...
Regardless of all the guesses, assumptions, dual conversion, triple conversion, etc.
The solution is DON'T TUNE TO 145.03.
 

w2xq

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Rather than turning the ATT on and muting the entire receiver, insert into the feedline a notch filter for 155.730 to knock down the signal strengh at that one frequency. Your search engine of choice will uncover both schematics and companies. [As an aside, my NRD-525 did strange things with a new local AM station with 50kw directional on 640 kHz. In the main lobe, the 525 showed a 90+ db/9 signal. A notch filter took it down to 50db/9, something the receiver easily handled.] Hope this helps.
 

ratboy

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My 525 was/is immune to any problems caused by the nearby station on 1560 these days, but in the past, it was pretty bad. At one point when they had a ground issue with their antennas, the high tension wires that passed by them and then went past my neighborhood were radiating the signal to the point I could peg the S-Meter on all my HF radios just by taking my finger and putting it near the antenna jack or terminal! My toaster also would pick up the station and it could be faintly heard when you were close to it unless it was actually making toast. Kind of a funny thing to show visitors. On the 525 and 515, the station could be heard anywhere under 10MHZ or so, either clearly or as a "ticking" type noise like it was a strong adjacent signal. I built a bunch of BCB band killers, and got the signal down to sane levels. My Kenwood R-5000 was affected the worst of them, it was heard all over the place until I put the filter on it. Even with it, it was heard in the background on a lot of different frequencies. I nagged the station about it for over a year, and finally someone called me and told me it would be "fixed" in a few days, and they were right, the signal strength went from, using my finger for an antenna, pegging the meter with 20 DB attenuation on the 515, to about 10db over, the best I could hope for. Luckily for me, they didn't increase their power when they got the OK to do so. Then I had a nearby transformer buzzing away, and the power company kept telling me "It's on our list!". Lightning put it at #1 one evening. I was never so happy to be without power for a couple of hours.
 

KE4RWS

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Regardless of all the guesses, assumptions, dual conversion, triple conversion, etc.
The solution is DON'T TUNE TO 145.03.
Unless you want to monitor a little packet radio traffic . . . :lol:

However, regarding the Pro-197's confirmed triple conversion receiver, apparently even that doesn't prevent either adjacent channel interference or an image to come through :(
 

KE4RWS

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Merry Christmas!!

I took it back to radioshack.

Merry Christmas everyone! :)

Andrew
I don't blame you there. As much as I love my PSR-600 / Pro-197, if I was experiencing unsatisfactory performance due to images or adjacent channel issues and was still within the bring-back period, I would have probably done the same thing.

I have a PSR-600 and a Uniden 996XT and love them BOTH. However, I have definitely noticed little issues each of them exhibit at times that seem to be unique to either model. Unfortunately there's no such thing as the *perfect scanner*, which is likely why many of us own more than one make and model to kind of offset for the issue you are experiencing (among other things). Well, that and the fact many of us enjoy monitoring multiple services at the same time :lol:

Perhaps you can try a different model that won't have the same result? Again, for me this is the reason I chose to go with two different manufacturers, as nothing would piss me off more than to have two high-end digital scanners only to have them rendered useless on certain frequencies because of some silly image or other internally generated issues :mad:

Good luck my friend, and Merry Christmas to you as well :)
 

gewecke

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Rather than turning the ATT on and muting the entire receiver, insert into the feedline a notch filter for 155.730 to knock down the signal strengh at that one frequency. Your search engine of choice will uncover both schematics and companies. [As an aside, my NRD-525 did strange things with a new local AM station with 50kw directional on 640 kHz. In the main lobe, the 525 showed a 90+ db/9 signal. A notch filter took it down to 50db/9, something the receiver easily handled.] Hope this helps.
if


Exactly. I can see a PAR notch filter in the future of my 197. I wouldn't need it if the two towers to my west would suffer sudden guy line failure! :twisted:
Between the noaa and paging transmitters, I'm lucky I hear local traffic.

73,
n9zas
 

jackj

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Image?

It's described that way in the user's guide:
If this spec listing is true then your problem shouldn't be caused by an image.

Originally Posted by The PRO-106 User's Guide
Receiver System
Triple conversion PLL super-heterodyne
1st IF.................................................. ............ 380.8 MHz
(The 1st LO uses high side of receive frequency
range for VHF and UHF Low/T, and low side of
receive frequency range for >512 MHz)
2nd IF .................................................. ............ 21.4 MHz
The second LO uses low side of 1st IF)
3rd IF .................................................. ................455 kHz
(The 3rd LO uses the low side of the 2nd IF)

The image frequency in the above case would be 761.6 MHz above or below the desired frequency. The image frequency is determined by the 1st IF frequency and is twice the IF frequency above for high side injection or below for low side.

I guess you took the radio back to RS and that is probably the best thing to do with it.
 
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