46.24 user

[retiredFD07]

I've been monitoring the freqs that "800" listed above. I've confirmed that 46.24 is in fact being used by Riverside City Electric Utility with a PL of 151.4. From what I can hear, it appears to be mobile use only but is repeated on the main 48.02 freq.

@ "800":
The 32.015 freq is valid, I'm hearing it all the time. It, too, is using 151.4 as a PL and is also repeated on 48.02.

I'd be interested if anyone can explain how this system is set up.

<>< Mike

[cvrules90]

Some agencies use low-band because there are far and few 39-47MHz band users. Some booney police and fire services, for example.

[Mike_G_D]

I've been monitoring the freqs that "800" listed above. I've confirmed that 46.24 is in fact being used by Riverside City Electric Utility with a PL of 151.4. From what I can hear, it appears to be mobile use only but is repeated on the main 48.02 freq.

@ "800":
The 32.015 freq is valid, I'm hearing it all the time. It, too, is using 151.4 as a PL and is also repeated on 48.02.

I'd be interested if anyone can explain how this system is set up.

<>< Mike

While the signal you are hearing on 32.015MHz is "valid" to you it may not really exist as part of the actual system you are monitoring; that is to say, the system (Riverside City Electric Utility) does not actually use that 32MHz frequency at all. You are receiving it in your receiver because of an undesired spurious mixing product which could be produced either within your receiver or by external means. What 800 stated is correct (as he usually is on such matters) - the 32.00MHz to 32.990MHz region withing the US is allocated to government usage and not to any civilian agencies. Therefor, it is highly unlikely that a frequency within that 1MHz band would be used by a city utility agency. So, if it is not "really there" then why does it appear so to you? Don't misunderstand me, of course, I have no doubt that you are actually hearing it and that your receiver is showing it as that frequency but I believe that it is because of undesired RF mixing products which can fool many listeners.

One very probable possibility is that a television channel 5 signal which contains its information between 76MHz and 82MHz for over-the-air and cable North American band plans is mixing with the utility transmission and resulting in that 32MHz "false" signal. If you take 32.015MHz and add it to 46.24MHz you get 78.255MHz which is within TV channel 5's bandwidth as is the sum of 48.02MHz and 32.015MHz (80.035MHz). It is especially likely with cable as your receiver may be located near enough to the TV cables to pick up strong leakage. With analog signals you could often tell because you could hear the second interferer as a lower level audio signal mixing with the primary desired audio (at least if it was the audio sub carrier) but with the newer ATSC (OTA) or QAM (cable) digital signals you may or may not hear anything and if you do, it wouldn't obviously be analog FM audio.

There are many other possibilities - strong clock signals from within the receiver's digital section or from a nearby computer or other electronic device, for example. In any case, without knowing your exact setup and situation, it would be nearly impossible to form a definitive answer; more data is required.

Here are a few questions I would ask:

1) What is the make and model of your receiver?

2) What kind of antenna are you using?

3) If portable or mobile then have you heard the 32MHz signal in multiple geographically disperse areas?

4) If you have access to different receivers especially from different manufactures can you verify that they all can hear the same 32MHz signal?

5) Can you determine whether the 32MHz signal is the same as the mobile input frequency signal on 46.24MHz or whether it is the same signal as the 48.02MHz output (the usual repeater sound versus a wavering or uneven simplex input sound)?

6) If you are hearing it strongly at home, try if at all possible to relocate the receiver to a very different location away from home and see what happens to the 32MHz signal.

Also, keep in mind that in North America the low band channelization scheme is such that the standard spacing is 20KHz across the band so no valid signal should end in xx.xx5; so, for example, a frequency could be 42.24MHz or 42.26MHz but not 42.245MHz or 42.255MHz or 42.265MHz. Just some possibilities to think through.

-Mike (different one)