Class "MO"

[bigk_54]

Hope this is the section for this, as the picture shows, this frequency was changed from the 159. Fb/fb2 Frequency (which came in loud and clear) to the 156. MO frequency that I can't seem to get this channel on my scanner, it is the local road commission so I don't think it would be anything secretive. Thanks for the help!

 

[teufler]

is it you can't program the 156.0525 frequency, because propagation wise, there is little difference between 159 and 156. the 156 frequenct is a mobile frequency while 159 is the base. If the system is a repeater, you will hear everything on the 159.180. Data shows its analog, tone of 173.8. The 156.0525 should be heard when mobiles are in proximity to you scanner location.

 

[mmckenna]

The 159.180 frequencies that are marked as FB or FB2 are the repeater output. Under the power column, you'll see that they are listed at 350 watts.
Those repeaters will be high on a hill with high gain antennas and running somewhere under 350 watts.

The 156.0525 and the 156.1200 are marked as MO, those are the mobile frequencies that the mobile and portable radios will use to transmit to the repeater. They are shown as 40 watts.

Based upon your location, you will very likely (as you noticed) hear the repeater output due to it's higher location and increased power. Not being able to hear the mobile/portables is not uncommon, unless they are close to you. This is the reason why the repeater is used. The high location of the repeater can "hear" the mobile and portable radios easier, and retransmit that received signal out to a wider area.

I'd suspect that one of the two 156.xxxx frequencies is the input to the repeater, and the second one is a simplex channel. If you could hear all three frequencies, you'd very likely hear that one of the 156 frequencies and the 159 frequencies were the same traffic.

 

[mmckenna]

Also, it would be worth pointing out that the "emission" shown for these frequencies covers 3 modes:
11K0F3E = narrow band FM analog
8K30F1E = 12.5KHz NXDN
4K00F1E = 6.25KHz NXDN

Not uncommon to see systems licensed like this. They are likely using the narrow band FM analog, but may change to one of the two NXDN modes in the near future. Often the radio shops will modify the license to reflect the new emission designators when the users purchase the new equipment. When they get all the equipment swapped out, they might switch to NXDN.

NXDN is a digital mode used in radios sold by a few companies, mostly Icom or Kenwood. There are not currently any consumer radio scanners capable of listening in on these systems without modifications. If you suddenly start hearing digital noise in place of the FM signal, you'll know they switched over.

 

[bigk_54]

NXDN is a digital mode used in radios sold by a few companies, mostly Icom or Kenwood. There are not currently any consumer radio scanners capable of listening in on these systems without modifications. If you suddenly start hearing digital noise in place of the FM signal, you'll know they switched over.

I believe you may have hit the nail on the head here. I've had heard from someone else they were told it was unscannable which baffled me, didn't know how that could be. The "159.18000 KQE851 RM 173.8 PL" was the old frequency and was loud and clear and within. The last year they got new radios in their trucks.

Thank you everyone good education here, you guys are great!