Peel, York and Toronto in 3GHz range?

[jonesyxvii]

Last night I randomly decided to scan the unknown with my Icom R20. To my surprise, I started picking up familiar voices, first Mississauga Fire, then Peel Police, GTAA...essentially the Peel trunk system. Seemed odd because I was around 3167.000! A bit more manually adjustment up and down and some listening to identify the systems (yes, plural) and after an hour or so this is what I had:


Simulcasts

Control Channels
3140.780
3137.580
3136.760
3136.080
3136.060

Peel Region Trunk System

Voice Channels
3137.740
3137.660
3137.560
3137.240
3137.160
3137.060
3136.740

Toronto Public Safety

Voice Channels
3142.540
3142.080
3141.780
3141.580
3141.540
3141.340
3137.760
3137.380
3136.880
3136.260

2869.120
2868.620
2865.160
2864.660
2863.920
1864.160

York Region Trunk System

Voice Channels
3141.080
3137.080

Unidentified Voice Channels
3142.780
3142.280
3142.040
3141.080
3137.860
2862.960 -- ?
2859.160 -- ?

I don't think this is an anomaly. I'm three kms from the nearest YRP tower in Richmond Hill and all of those same frequencies are still active this morning. I'm at a loss to explain it. Can anyone shed some light?

 

[cpuerror]

Probably just receiving images from the 800Mhz band.

 

[W4ELL]

Yeah, I think cpuerror is correct... it has to be images from the 800Mhz band.

Some multiple of the R20's IFs:

266.7 MHz
429.1 MHz
19.65 MHz
450 kHz

I use to pick up images from the 800 Mhz cell band on 900 Mhz on my old Pro 51.

 

[jonesyxvii]

What's an image? What causes it? I've never heard that term in this context before.

 

[torontokris]

Some general reading on image frequency (gets a little complex). Hope that helps and is on topic.

Superheterodyne receiver - Wikipedia, the free encyclopedia

What's an image? What causes it? I've never heard that term in this context before.

 

[moonbounce]

The IF frequency should be located at the back of the radio's user manual. For most radio's it is around 21 Mhz, so 21 Mhz plus the frequency of the signal you are receiving, I don't think that would take you up into the 3Ghz area, I could be wrong as these new radios today are much different than previous radios.

MB

 

[DaveH]

The IF frequency should be located at the back of the radio's user manual. For most radio's it is around 21 Mhz, so 21 Mhz plus the frequency of the signal you are receiving, I don't think that would take you up into the 3Ghz area, I could be wrong as these new radios today are much different than previous radios.

MB

Reminds me of the time I found a Motorola trunked CC down around 32MHz on my old
BC235 (a triple-conversion RX). At first I was thrilled, pretty novel, maybe it's military or
something different. Turns out it was actually on 850MHz, somehow a case of overload
and mixing products.

Many older dual-conversion receivers had 1st IF's around 10.7-10.8MHz or 21.x MHz but a receiver
which covers up to and above 3GHz is very unlikely to (as are most newer receivers that are triple-conversion).

Suffice to say that said agencies are not actually transmitting up there, at least not on stated
frequencies, and it's a receiver "spurious response".

Dave

 

[moonbounce]

Reminds me of the time I found a Motorola trunked CC down around 32MHz on my old
BC235 (a triple-conversion RX). At first I was thrilled, pretty novel, maybe it's military or
something different. Turns out it was actually on 850MHz, somehow a case of overload
and mixing products.

Many older dual-conversion receivers had 1st IF's around 10.7-10.8MHz or 21.x MHz but a receiver
which covers up to and above 3GHz is very unlikely to (as are most newer receivers that are triple-conversion).

Suffice to say that said agencies are not actually transmitting up there, at least not on stated
frequencies, and it's a receiver "spurious response".

Dave


Reminds of my old Realistic Pro 20/20, (which I still have) I used to pick up phone conversation in the middle of the aircraft band, 118 to 136 Mhz, at the time I lived out in the country. I tried doing a search with another radio but I could never find the conversation on the original frequency. It was almost like I was picking up cell phones, I had searched 40 to 50 Mhz and 148 to 174 mhz with no luck.

MB