frequency 766.643750 Question

[gmt48]

Thanks in advance to anyone who can offer some insight and/or advice. I have a question regarding 766.643750 MHz.

BACKGROUND INFO:
I have very limited radio communication knowledge.
Scanner: GRE PSR310
Antenna: Radio Shack #20-283 800MHz
Scanner Software: PSREdit
Location: Gig Harbor, Pierce County, Washington

ISSUE:
When running through its scan cycle the search often stops on frequency 766.643750. Here's a photo:

I know the PSR310 has the capability to scan 764-782 MHz in the 800 MHz Band.
I am not able to hear any communications on that frequency.
I know that frequency is in a range used by police, fire and EMS.
I can see the frequency is identified in the above photo on the scanner as Gig Harbor Police and Fire.
I do not have 766.643750 MHz listed on any of my scan lists or programmed into the scanner.
I do have ID 0095 in my scan list as Gig Harbor Fire (mobile) at 153.830000.
I do have ID 0096 in my scan list as Gig Harbor Fire (base) 153.890000.
I cannot find 766.643750 MHz listed in the any of the popular radio frequency databases including Radio Reference and Intercept Radio.

QUESTION:
What is this frequency, why isn’t it listed anywhere (that I can find) and why can’t I hear anything on it?

SIDE NOTE:
I have the Green Mountain Repeater 146.88000 MHz programmed in (don't know why) as a conventional object on my scan list. Could this have something to do with it? Is programming that repeater in a scan list something I should keep or remove?

Again, thanks in advance for any assistance.

Greg
.

 

[Stavro35]

Could it be an image of a true frequency?

 

[gmt48]

Could it be an image of a true frequency?

Please excuse my ignorance, but I don't know what you mean by "a true frequency". Would you please elaborate?

 

[gmt48]

Still looking for answers or ideas. Any help will be greatly appreciated.

 

[RBMTS]

As per the previous OP response, you are probably hearing an "Image" of a different frequency or even just RFI interference generated by other nearby electronic devices in the room with your scanner. Scanners are very wide band and can pickup stray local signals not related to a radio transmission. It might also be an internal "birdie" generated by your scanner itself. All scanners have them. It is internally generated frequency interference from the microprocessor.

Hope this helps you.

 

[gmt48]

RBMTS: That explains a lot. Its obvious I have much to learn. Now I can stop freaking out and taking the anxiety meds . Thanks to both you and Stavro35 for taking time to help a newbie who had a question that must be so elementary to you.

- Greg

 

[DickH]

Could it be an image of a true frequency?

Impossible, since the 1st IF of a PSR-310 scanner is 380.8MHz.

 

[DickH]

RBMTS: That explains a lot. Its obvious I have much to learn. Now I can stop freaking out and taking the anxiety meds . Thanks to both you and Stavro35 for taking time to help a newbie who had a question that must be so elementary to you.

- Greg

I suspect you only see 766.64375 when someone at Gig Harbor transmits on 153.83. That may be mixing with some other freq., resulting in 766.64375 showing up on your display.
It would be easy enough to verify if you have another scanner and park it on 153.83.

 

[gmt48]

I suspect you only see 766.64375 when someone at Gig Harbor transmits on 153.83. That may be mixing with some other freq., resulting in 766.64375 showing up on your display.
It would be easy enough to verify if you have another scanner and park it on 153.83.

Thanks for your input, DickH. Unfortunately, I don't have another scanner. For now, I'm just not going to worry about that frequency any more and just chalk it up as an anomaly.

BTW, I visited your website; great photography.

 

[SCPD]

Do you hit on this frequency without the antenna? If so, it could be an internal birdie of the scanner.

There is no 700mhz law enforcement activity in this area -- yet. Pierce transit and King County Metro Transit are using 700mhz right now.

They are using P25 which your scanner won't decode but you would hear a digital noise.

 

[gmt48]

Do you hit on this frequency without the antenna? If so, it could be an internal birdie of the scanner.

Thanks, nickcarr. No, I have never operated the unit without the antenna attached.

 

[SCPD]

Well, try it. If the scanner stops on the frequency w/o the antenna attached then it's a birdie.

You're not going to damage the scanner.

 

[DickH]

BTW, I visited your website; great photography.

Thanks. It's easy when there are such great subjects as Portland Fire presents.