381.8625 & Other 300Mhz Freqs.

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KC9NCF

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Ok, setting up my 8900R to receive aircraft / dispatch freqs as listed in the CARMA O'Hare profile today. I decided to take a break and scan through because I was hearing images on the freqs CARMA listed. good luck hearing anything at O'Hare due to the signal strength! (I even put the radio into AM mode)

Not sure what I'm hearing...the first one is self explanatory: 381.8625 was some sort of transport going to Terminal 5. (dropping someone off). 381.7625 appears to be some sort of fueling or other operations in Polish language or language similar to it.

From the CARMA profile: 363.800 FM possible images from UIC Police? 381.450 = unknown, but keep hearing unidentified keying in very short half second bursts.

365.4125= Wheel Of Fortune

365.550= Television program (celeb gossip)

369.950= CPD Image (Zone 2)
Lots more CPD images found on 300Mhz.

370.925 = Hospital Security somewhere (possible image)

381.5375 (Non airport related transport)

381.475 = (non-airport related transport)

Encrypted / Possibly digital P25? = 364.325

Anything good actually ON the 300Mhz band?
 

ka3jjz

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Not entirely true - some freqs in the 380 mhz range are being used by new P25 trunk systems across the country, mostly at mil bases and some fed. These would be in FM mode - so anything in AM is possibly aircraft ops, which still exists in parts of this band. The newer digital trunktrackers (396, 996, PSR-500 and 600) can trunktrack in these bands.

That being said, it wouldn't surprise me if the 8900 was hearing images, overload and other junk. Not every ham radio that says it covers this band actually does so well. Sounds to me like you're getting clobbered by overloading, frankly

73 Mike
 
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KC0QNB

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look here for a frequency allocation table.

335.4-387
FIXED
MOBILE

641 335.4-399.9 FIXED
MOBILE

G27 G100
The FAA provides air traffic control communications to the military services on selected frequencies in this band.
387-390
FIXED
MOBILE
this is a copy and paste of part of the table. as to what kind of traffic is here I do not know. well the translation from table to text didn't work right, look at the table for yourself.
 

chgomonitor

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8900r?

I assume that is a Yaesu amateur radio. Most of the current Yaesu crop is notorious for hearing images of UHF land mobile stuff in the 406-480 range while tuning in the 300 MHz range. All of the signals you report hearing are images, not real signals.

These days it is actually somewhat rare for O'Hare to have their UHF air traffic control simulcast transmitters up and running. I'd suggest checking 269.900 (AM) to see if you can first hear the ATIS simulcast of 135.400 (AM). You might also try 317.400 for Chicago Center in Des Plaines.
 

KC9NCF

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From the CARMA O'Hare Airport Profile:

S/W APPROACH:
125.700 / 363.800
S/W FEEDER:
135.075 / 381.450

There is a link here at RR to this profile at the CARMA site.
 
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