Does anyone else notice when listening to 129400 am AIRINC that the audio keeps disappearing every two seconds, like I have close call on, it only happens on this frequency. Using a Uniden 436 scanner.
Saint
Saint
129.400 am AIRINC
- Thread starter Saint
- Start date
Does it drop out momentarily and come back or does it drop out and stay silent for a while?
If it is the first one, my hunch is that this may be Close Call Primary mode or Priority Scan Primary Mode in the scanner.
If it is the first one, my hunch is that this may be Close Call Primary mode or Priority Scan Primary Mode in the scanner.
When I heard the med emerg yesterday I didn't notice any drop outs on 129.400.
Not familiar with 129.4, but many years ago when I was in the two-way business, there were phone patches designed that could operate on simplex channels.
They had a voice operated relay (VOX) that keyed up the radio from the phone line. Then depending on the equipment, they had logic that after a set amount of time (in setup), would start sampling to see if the mobile was responding. This helped to keep noisy phone lines from keying the transmitter and never dropping. So every few seconds the base transmitter would drop for a few hundred milliseconds, and if it heard signal from the mobile it would pass that audio to the phone line, and prevent the base from keying back up.
When the mobile stopped keying, if the audio was high enough from the phone side it would again key the base transmitter.
So if you were hearing the base station you would hear a drop every few seconds to 'sample' for a response from the mobile.
Depending on how they were connected, it my have been a phone patch operation that used similar logic, rather than a dedicated remote control or console where someone actually pushes a button (PTT) to transmit, and there is no need to 'sample'.
They had a voice operated relay (VOX) that keyed up the radio from the phone line. Then depending on the equipment, they had logic that after a set amount of time (in setup), would start sampling to see if the mobile was responding. This helped to keep noisy phone lines from keying the transmitter and never dropping. So every few seconds the base transmitter would drop for a few hundred milliseconds, and if it heard signal from the mobile it would pass that audio to the phone line, and prevent the base from keying back up.
When the mobile stopped keying, if the audio was high enough from the phone side it would again key the base transmitter.
So if you were hearing the base station you would hear a drop every few seconds to 'sample' for a response from the mobile.
Depending on how they were connected, it my have been a phone patch operation that used similar logic, rather than a dedicated remote control or console where someone actually pushes a button (PTT) to transmit, and there is no need to 'sample'.
BC_Scan
Member
not over here same fx , periods where no audio but good carrier same fx @ San Fransisco
close call is off and priority scan also. I have no problems with other frequencies.
Saint
