VHF scanning

[sonm10]

I have gotten good at scanning uhf band, but vhf high has gotten the bast of me. For those who scan vhf high band, what is a good start, stop frequencies and step size.

Uniden does 5khz step s which is too slow. If I use 15khz, some frequencies are off by 50hz. Any suggestions? Thanks

 

[Whiskey3JMC]

For those who scan vhf high band, what is a good start, stop frequencies and step size.

If you want to scan the entire VHF high wavelength you'll want to start at 150 and end at 174mhz (or stop at 162 to avoid NOAA weather frequencies), 5 khz step size is a good start point, I've rarely had any issues missing traffic with this step size

 

[GTR8000]

7.5 kHz is the correct step size in most of the VHF band, not 5 kHz. If you use 5 kHz, the scanner will not stop on the correct center frequency for the post-narrowband interleaved frequencies, which are pretty ubiquitous at this point. Example: the scanner may stop on 155.045 or 155.050 instead of the correct center frequency of 155.0475.

If you're using a Uniden scanner to search the VHF band, set the 150.8 band to NFM and 7.5 kHz

 

[sonm10]

7.5 kHz is the correct step size in most of the VHF band, not 5 kHz. If you use 5 kHz, the scanner will not stop on the correct center frequency for the post-narrowband interleaved frequencies, which are pretty ubiquitous at this point. Example: the scanner may stop on 155.045 or 155.050 instead of the correct center frequency of 155.0475.

If you're using a Uniden scanner to search the VHF band, set the 150.8 band to NFM and 7.5 kHz

View attachment 112782

THANK YOU!!!

 

[Ubbe]

I would suggest to check the FCC license approvals, I think they are here at RR or are linked to, to see what the local transmitters are using for a step size. Then download a demo program for a Uniden scanner from butel.nl and create scanlists by using the Fill feature. You can tailor make the scanlists that way and simply copy and paste the whole frequency range into a suitable Uniden program. Also when doing avoid in search lists you can only save up to 255 avoids, then it starts to overwrite the oldest ones which will then be unavoided, but permament avoids in scanlists have no limits.

/Ubbe

 

[GTR8000]

I would suggest to check the FCC license approvals, I think they are here at RR or are linked to, to see what the local transmitters are using for a step size.

Transmitters don't use a "step size", they use transmitter deviation aka modulation bandwidth. Those are two very different things. Step size, aka frequency spacing, only comes into play when searching a band, not when scanning pre-programmed frequencies.

 

[NowhereMan66]

7.5 kHz is the correct step size in most of the VHF band, not 5 kHz. If you use 5 kHz, the scanner will not stop on the correct center frequency for the post-narrowband interleaved frequencies, which are pretty ubiquitous at this point. Example: the scanner may stop on 155.045 or 155.050 instead of the correct center frequency of 155.0475.

If you're using a Uniden scanner to search the VHF band, set the 150.8 band to NFM and 7.5 kHz

View attachment 112782

I've run into that problem with the Pro-43 for analogue transmission but I still receive the signals OK even if I'm off 2.5 kc.

 

[GTR8000]

I've run into that problem with the Pro-43 for analogue transmission but I still receive the signals OK even if I'm off 2.5 kc.

The scanner will likely stop on the nearest frequency, but you won't have the correct center frequency. That can be an issue when trying to find a matching FCC license or when submitting to the RR database. And of course if there are users of the adjacent frequencies, you may wind up picking up both transmissions simultaneously.

 

[Ubbe]

Transmitters don't use a "step size",

They use step size between different transmit licenses and you check what the step sizes are in several local FCC licenses. If one license have 160.025 and another 160.050 and you constantly see that 25KHz step in that band, then you use that step to create a frequency range in a scan list. If you see 160.0125 and 160.025 then they use a 12,5KHz step size for that frequency band. But there will probably be a bigger difference between frequency licenses like 160.025 and 161.6125 and then you'll know that they use a 12,5KHz step size as a 25KHz will not match with 161.6125 and the same reasoning will be done if they use 7,5KHz, 20Khz or 50KHz step sizes just by studying their FCC licenses. It's not rocket science.

/Ubbe

 

[GTR8000]

They use step size between different transmit licenses and you check what the step sizes are in several local FCC licenses. If one license have 160.025 and another 160.050 and you constantly see that 25KHz step in that band, then you use that step to create a frequency range in a scan list. If you see 160.0125 and 160.025 then they use a 12,5KHz step size for that frequency band. But there will probably be a bigger difference between frequency licenses like 160.025 and 161.6125 and then you'll know that they use a 12,5KHz step size as a 25KHz will not match with 161.6125 and the same reasoning will be done if they use 7,5KHz, 20Khz or 50KHz step sizes just by studying their FCC licenses. It's not rocket science.

/Ubbe

With all due respect, I'm much more familiar with the licensing in the U.S. than you would be, and my previous comments stand. The Part 90 PLMRS VHF band in the U.S. post-narrowbanding uses 7.5 kHz spacing as a rule.

 

[NowhereMan66]

The scanner will likely stop on the nearest frequency, but you won't have the correct center frequency. That can be an issue when trying to find a matching FCC license or when submitting to the RR database. And of course if there are users of the adjacent frequencies, you may wind up picking up both transmissions simultaneously.

Point taken, just saying that if you only have 5 kc steps on your scanner, it is still doable to receive those signals. When I lived near Greater Pittsburgh Airport, I monitored the 911th Air Force Reserve and 171st Penna Air Natl'l Guard Wing (and 112 Fighter Wing when we had the A-7's) , sometimes their frequencies were 2.5 kc off but was still came in load and clear. I can see the problem if you are trying to determine the correct frequency to identify the users. I bet during the days of analogue tuning, it was a huge problem too.