SDS100/SDS200: Scanner "Sticks" on Aircraft Frequency

[fredva]

Recently, I've noticed that my SDS-100 will stop on an AM aircraft frequency and will not continue scanning, even though there isn't any audible traffic on the frequency. I often monitor the frequencies for the local general aviation and regional airports, and 122.8 seems to be the frequency that the scanner locks on. I think this happened once when I was monitoring commercial aviation frequencies as well. I checked my filter settings and the filter was set to "Off" for 122.8. I changed it to the global filter of Wide Invert but the problem continues. The problem will happen in the car and at home, so I'm not sure there is a single source of interference that might be contributing. Any ideas how to fix this? The squelch level is at 2 and hasn't changed in years.

 

[doctordialtone]

Try the IFX setting to change the IF Frequency.

 

[n1chu]

122.8 MHz is the UNICOM frequency for Robertson Airport in Plainville Ct. I live close and don’t get the same “hang” after a transmission… but you could try the IFX fix mentioned by doctordialtone, nothing to loose. If you live close we could meet at the airport if you don’t get it straightened out.

 

[doctordialtone]

. If you live close we could meet at the airport if you don’t get it straightened out

That would be quite a commute!

 

[donc13]

Next time it stops on that freq, hit the avoid key twice to permanently lock it out. and problem solved.

 

[iMONITOR]

Recently, I've noticed that my SDS-100 will stop on an AM aircraft frequency and will not continue scanning, even though there isn't any audible traffic on the frequency. I often monitor the frequencies for the local general aviation and regional airports, and 122.8 seems to be the frequency that the scanner locks on. I think this happened once when I was monitoring commercial aviation frequencies as well. I checked my filter settings and the filter was set to "Off" for 122.8. I changed it to the global filter of Wide Invert but the problem continues. The problem will happen in the car and at home, so I'm not sure there is a single source of interference that might be contributing. Any ideas how to fix this? The squelch level is at 2 and hasn't changed in years.

Set the squelch higher, maybe 3 or 4 see if that helps. Possibly the background noise is higher than it used to be. Or try a FM notch filter.

 

[RFI-EMI-GUY]

Close Call turned on??

 

[n1chu]

That would be quite a commute!

View attachment 131733

That’s why I included town and state of Robertson… it’s understood the frequencies are used over and over with proper spacing…

 

[ka3aaa]

adjust the squelch to a tighter setting

 

[wtp]

birdie maybe ?
take the antenna off and scan again, if it locks up, it is a birdie.

 

[fredva]

Thanks for the responses. I am attempting to use the IFX setting now to see if that helps. If not, I will try something else. Something I didn't mention in my previous post is that when the scanner sticks on the frequency, the signal bar shows a signal that varies in strength. If I intentionally hold on that frequency, no signal is shown.

 

[darkness975]

Next time it stops on that freq, hit the avoid key twice to permanently lock it out. and problem solved.

This is what I would do. I have had to for a couple weird channels before. I occasionally check to see if they've been fixed.

 

[RichardKramer]

What I would try if none of the above works (I have the BCD436); change the band setting default to 5KHz (it's probably set to 25KHz now), and program the freq as either 122.795 or 122.805 which may be off freq enough to eliminate the rfi and you will still be able to hear tx on 122.8. Does the SDS 100 have an attenuator? You could try that also, but then the range you pick up a/c will be reduced. If one those offset freqs work; you can go back and change the default setting to 25KHz once you have the offset freq programmed.

 

[fredva]

This is what I would do. I have had to for a couple weird channels before. I occasionally check to see if they've been fixed.

Well, the problem with that is that I actually want to listen to the planes using this frequency. If there is a way to eliminate the issue while still being able to pick up legitimate radio transmissions, I'd prefer to go that route first. And if I eventually realize that the scanner is stuck on the frequency, I can turn the knob and get the scanning going again, and the problem may not happen for another hour or longer. It's not sticking on the frequency every time it scans it, so a permanent lock out seems like overkill. It is an annoyance though, and I can miss transmissions on other systems when it gets stuck.

 

[DudleyG]

Have you tried turning on ATTENUATOR for that one frequency? That will cause a drop of 20dB on that one frequency but you should be able to still receive strong signals. It will also help eliminate RF interference from other sources that are hitting that one frequency.

 

[N5XPM]

Well, the problem with that is that I actually want to listen to the planes using this frequency. If there is a way to eliminate the issue while still being able to pick up legitimate radio transmissions, I'd prefer to go that route first. And if I eventually realize that the scanner is stuck on the frequency, I can turn the knob and get the scanning going again, and the problem may not happen for another hour or longer. It's not sticking on the frequency every time it scans it, so a permanent lock out seems like overkill. It is an annoyance though, and I can miss transmissions on other systems when it gets stuck.

This will require much experimentation to achieve in the AM aircraft band without missing radio transmissions you want to hear. You may have better results with the purchase of an additional scanner dedicated to the aircraft band.

 

[RichardKramer]

Have you tried turning on ATTENUATOR for that one frequency? That will cause a drop of 20dB on that one frequency but you should be able to still receive strong signals. It will also help eliminate RF interference from other sources that are hitting that one frequency.

I mentioned that in Post #13.

 

[AA4BK]

Why not just set a negative delay value? OP said the scanner doesn't get stuck every time it scans the frequency, and it can go for an hour without getting stuck, until some certain transmission gums it up. So just set a negative delay value, -3 or whatever (however many seconds you want it to delay) and it will force itself to continue after that many seconds. Problem solved.

 

[wtp]

have you checked this with another radio ?

 

[Ubbe]

If IFX doesn't work, then try each filter setting. I have a -105dBm noise floor at 122.800 but goes to -115 using IFX. When I use the Normal filter at a 118MHz frequency I drop to -125dBm or just dashes. All this with squelch set to 0 as if the squelch doesn't open it will not show any signal strength bars or dBm values.

If you get signal indicating when it stops at scan but disappears when you push hold, then it's probably a signal that are internally generated in the scanner. Try and turn off the display, quick push on the On/Off button, to hear if the signal goes away and starts to scan again.

/Ubbe