bc246t closecall not working?

[dustin486]

Today I drove down "fast-food lane" (a road here that is pretty much nothing but fast food stuff, mcdonalds, etc) with close call enabled on my 246t. It didn't pick up a single hit.

I am wondering if I may be doing something wrong? I tried pressing func+hold and I tried selecting "Close Call Only" in the menu. Neither ever picked up a hit. I tried using an external antenna on a vehicle and the default rubber duckie. Do I maybe have some settings wrong?

Note: I checked the closecall configuration in the menu and all bands are enabled. No options appear to be "obviously" wrong.

Also, does anyone elses have issues with trunktracking an LTR standard system? Sometimes I can hear the data bursts from the repeaters, and other times it will get "stuck" on a talkgroup.

Thanks

 

[Voyager]

Today I drove down "fast-food lane" (a road here that is pretty much nothing but fast food stuff, mcdonalds, etc) with close call enabled on my 246t. It didn't pick up a single hit.

I am wondering if I may be doing something wrong? I tried pressing func+hold and I tried selecting "Close Call Only" in the menu. Neither ever picked up a hit. I tried using an external antenna on a vehicle and the default rubber duckie. Do I maybe have some settings wrong?

Note: I checked the closecall configuration in the menu and all bands are enabled. No options appear to be "obviously" wrong.

Also, does anyone elses have issues with trunktracking an LTR standard system? Sometimes I can hear the data bursts from the repeaters, and other times it will get "stuck" on a talkgroup.

Thanks

Those systems use VERY low power. It's not unusual to NOT be able to pick up those, cordless phones, baby monitors, or any such low power devices unless you're within a couple feet of the transmitter (which is usually behind the counter) or the headset.

Remember, the signal much not only be 15-20 dB above the noise floor, but also 15-20 dB stronger than any other transmitter in range - including any paging transmitters. That's asking a lot of such a low power signal.

You shouldn't be hearing the LTR beacons if it's scanning in LTR mode.

Joe M.

 

[dustin486]

Ok, thanks. I think I understand the close call now.

On the LTR stuff, it is scanning in LTR mode. I'm seeing LTR id's show up now (0-05-121 for Dispatch 1). I can also hear random (note random, they aren't in 10 seconds intervals, so im not hearing all of the data bursts like i do if i listen to the frequencies in non-ltr mode) data bursts. Normally they are on like 0-0x-248 and 249.

 

[UPMan]

In such low-signal circumstances, you might get better results in Close Call Only mode by opening squelch all the way. Sometimes in an RF clean environment, a low-level signal is enough to trigger Close Call, but if it isn't strong enough to open squelch, the scanner will ignore it. Opening squelch all the way bypasses that final check.

 

[MacombMonitor]

Don't expect too much from "Close Call". Personally I think its overated.

 

[W4KRR]

Today I drove down "fast-food lane" (a road here that is pretty much nothing but fast food stuff, mcdonalds, etc) with close call enabled on my 246t. It didn't pick up a single hit.

I am wondering if I may be doing something wrong? I tried pressing func+hold and I tried selecting "Close Call Only" in the menu. Neither ever picked up a hit. I tried using an external antenna on a vehicle and the default rubber duckie. Do I maybe have some settings wrong?

Voyager's answer (as usual) was right on target.

I have found that if you drive through the McDonald's drive thru, you can pick them up once you're at, or close to, the pick up window. As was pointed out, they use very low power.

Usually their transmitter is a white plastic box with a couple of rubber duck antennas on top, mounted inside on the wall in the vicinity of the drive thru window. Or, if you go inside and sit, you should easily hear them.

quote="MacombMonitor"]Don't expect too much from "Close Call". Personally I think its overated.[/quote]

IMO, it works fine, if you know what you can and cannot expect to receive. The Radio Shack PRO-97's Signal Stalker picks up transmissions from much farther away that Close Call does, but this is by design. This may or may not be a good thing depending on your needs or expectations. Despite this, I cannot receive fast food drive thru windows with Close Call or Signal Stalker just by driving down the road. YMMV.

 

[Voyager]

Don't expect too much from "Close Call". Personally I think its overated.

If you think it's overrated, your expectations are too high.

It works about as well as ANY nearfield frequency counter. Perhaps you don't understand the limitations of nearfield capture.

Close Call is more than just a 'fast search' mode.

Joe M.

 

[Al42]

Remember, the signal much not only be 15-20 dB above the noise floor, but also 15-20 dB stronger than any other transmitter in range

Capture ratio (that's what "stronger than any other transmitter" refers to) is a function of the detector, not the receiver sensitivity, and a 15db capture ratio is pretty bad for a 1949 FM broadcast radio. I don't know the exact spec for any Uniden scanner - or whether they even measure it (UPMan could probably find out) - but I suspect it's much better than that, maybe on the order of 6db or even less.

 

[Voyager]

Remember, the signal much not only be 15-20 dB above the noise floor, but also 15-20 dB stronger than any other transmitter in range

Capture ratio (that's what "stronger than any other transmitter" refers to) is a function of the detector, not the receiver sensitivity, and a 15db capture ratio is pretty bad for a 1949 FM broadcast radio. I don't know the exact spec for any Uniden scanner - or whether they even measure it (UPMan could probably find out) - but I suspect it's much better than that, maybe on the order of 6db or even less.

No, it's not simply 'stronger than any other transmitter'. No nearfield receiver will do that that I know of, and I have several. They all spec 10-20 dB stronger than ANY other signal. I believe the exact Uniden spec is 18 dB. Maybe Paul would confirm that.

Joe M.

 

[Al42]

No, it's not simply 'stronger than any other transmitter'. No nearfield receiver will do that that I know of, and I have several. They all spec 10-20 dB stronger than ANY other signal. I believe the exact Uniden spec is 18 dB. Maybe Paul would confirm that.

Are we talking about receiving the signal, or just feeding it into a broadband counter? I've never seen the schematic so I have no idea, but that sounds like a counter, not a receiver.

 

[Voyager]

No, it's not simply 'stronger than any other transmitter'. No nearfield receiver will do that that I know of, and I have several. They all spec 10-20 dB stronger than ANY other signal. I believe the exact Uniden spec is 18 dB. Maybe Paul would confirm that.

Are we talking about receiving the signal, or just feeding it into a broadband counter? I've never seen the schematic so I have no idea, but that sounds like a counter, not a receiver.

Well, the finding of the frequency is done as a nearfield counter, then the receiver is tuned to the same frequency. The nearfield counter has the same limitations as any other nearfield counter. But, once the receiver is tuned to the frequency, it's the same as if you entered the frequency directly - the sensitivity to the signal is the same as any other 'channel'.

The 18 dB stronger than the noise floor (AKA any other signal in the same band) is in reference to the nearfield counter (frequency/signal finder).

Joe M.

 

[Al42]

The 18 dB stronger than the noise floor (AKA any other signal in the same band) is in reference to the nearfield counter (frequency/signal finder).

Ok, that I can accept. It could be better, and is - on counters doing nothing else, and costing more than a 396.

 

[scanfan03]

Ok, that I can accept. It could be better, and is - on counters doing nothing else, and costing more than a 396.

Next time you get a hit, press hold while it is showing the frequency, and you will have the same sensitivity as any other channel like Voyager said. If it is in the UHF low band you may have to press func, rev to get the repeater output.

 

[Voyager]

The 18 dB stronger than the noise floor (AKA any other signal in the same band) is in reference to the nearfield counter (frequency/signal finder).

Ok, that I can accept. It could be better, and is - on counters doing nothing else, and costing more than a 396.

Such as.... ? Even my Opto units are at least 10 dB.

Joe M.

 

[Al42]

The 18 dB stronger than the noise floor (AKA any other signal in the same band) is in reference to the nearfield counter (frequency/signal finder).

Ok, that I can accept. It could be better, and is - on counters doing nothing else, and costing more than a 396.

Such as.... ? Even my Opto units are at least 10 dB.

Which is a lot better than 18db, but I was thinking of some of the old HP counters. Don't ask me for model numbers - the last one I had was retired decades ago.