BCD396T Close Call Questions

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benzrider2000

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I've been playing around with the Close Call functionality and it seems like a pretty cool feature. Does anyone know the actual range that it picks up though and how strong the signal has to be?

I was in the Carl's Jr drive through and setup Close Call to see if I could pick up the signal. It worked just fine and I listened for a little while for the fun of it. It's actually pretty darn funny to listen in to what people say in the drive through. Anyway, I wanted to try out scanning the frequency by setting up a custom scan from 496.0 to 496.9 (the Cj's freq is 496.0125) and when scanning just those freq's, it never picked up the Cj's signal.

Does anyone have some answers and some more detail about Close Call? Thanks!
 

rbm

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I find CC on the BCD396T very annoying because it constantly interrupts normal scanning/listening. I rarely use it anymore on the 396. However, it's MUCH better on the BCD996T & BCT15.

Here's what my experience was when I first got the 396 and was still getting the feel for it.

If you hook the scanner up to a good base antenna the hits in the air band can be annoying. Sometimes every 5-10 minutes. I had to create a custom broadcast band for 108-137 MHz.

In the car using a trunk mounted antenna I've picked up mobile radios up to 1/4 mile from me. Hand held units 100-200 yards at most.

Obviously you have to be a much closer using the duck. (Several hundred yards at most for mobile units.)

I have quite a few BCD996T's and BCT15's in my den and at times they'll all get a close call hit within 2 seconds of each other. At other times, only one or two will.

Rich
 
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benzrider2000

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I have the close call turned off while normal scanning because it does interrupt the broadcast every two seconds with dropouts.

I only use close call if i'm trying to pick something up and I do a search of CLOSE CALL ONLY with no other scanning. I have a magnetic car mount antenna that I use sometimes and the range is pretty nice but I haven't tested it too much with close call searches...

I'm using a Diamond Antenna SRH77CA whip antenna instead of the duck that came with it on a recommendation from the store where I bought the scanner.

Would anyone know why I wouldn't pick up a broadcast that I know exists, by scanning within that range? If I type it directly in, I get signal with at least 2 bars...???
 

LEH

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I have the close call turned off while normal scanning because it does interrupt the broadcast every two seconds with dropouts.

I only use close call if i'm trying to pick something up and I do a search of CLOSE CALL ONLY with no other scanning. I have a magnetic car mount antenna that I use sometimes and the range is pretty nice but I haven't tested it too much with close call searches...

I'm using a Diamond Antenna SRH77CA whip antenna instead of the duck that came with it on a recommendation from the store where I bought the scanner.

Would anyone know why I wouldn't pick up a broadcast that I know exists, by scanning within that range? If I type it directly in, I get signal with at least 2 bars...???
What I believe the close call function does is do a rapid scan through a range and if there is enough signal strength, it will start narrowing the search down. So if you are not close enough for the scanner to 'feel' that level of strength, it won't stop for the signal.

Now if you set up your custom search for the desired range, it will stop on the signal much further away.
 

UPMan

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What I believe the close call function does is do a rapid scan through a range and if there is enough signal strength, it will start narrowing the search down. So if you are not close enough for the scanner to 'feel' that level of strength, it won't stop for the signal.

Now if you set up your custom search for the desired range, it will stop on the signal much further away.
That would be incorrect. It uses a patented frequency capture method that is similar to how a frequency counter works. If there is a signal strong enough to result in a stable frequency, then it detects, counts, then tunes to that frequency. It never, ever "sweeps."

It does a seperate check on each enabled CC band, though. In general, it can determine that there is no "signal of interest" within less than 100 mS for all the bands (10-20mS per band). If there is a signal of interest, it typically detects and tunes to that frequency within 100 mS. Sweeping would take much longer.

As to the range...that will depend on the receiving antenna, the transmit power and distance to the target, the transmit power and distance to all other in-band signals...

It takes a signal about 15-18dB above the noise floor and any other signal in the band to generate a hit (which generally only happens when the call is quite close, hence the name).
 

LEH

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That would be incorrect. It uses a patented frequency capture method that is similar to how a frequency counter works. If there is a signal strong enough to result in a stable frequency, then it detects, counts, then tunes to that frequency. It never, ever "sweeps."

It does a seperate check on each enabled CC band, though. In general, it can determine that there is no "signal of interest" within less than 100 mS for all the bands (10-20mS per band). If there is a signal of interest, it typically detects and tunes to that frequency within 100 mS. Sweeping would take much longer.

As to the range...that will depend on the receiving antenna, the transmit power and distance to the target, the transmit power and distance to all other in-band signals...

It takes a signal about 15-18dB above the noise floor and any other signal in the band to generate a hit (which generally only happens when the call is quite close, hence the name).
Thank you for setting me straight there Paul. At least I had the strength level right. :D

You did bring up one point that some may have missed. I recall one poster saying something about the hits in the air band (I worked near a commercial FM station for a while) being a problem. The CC bands may be set in the program menu. If there is a specific frequency range you don't want checked, deselect it. I have dropped the commercial FM band to avoid them being captured.

With just a Diamond SRH519 antenna (my 'stock' antenna for the 396), I have picked up signals as far away as 1/2 mile. The VSP have a tower about that far from a major intersection with an output of 350 watts. There is a taxi company a bit further down the road (unknown output) that I can get at 1/4 or so miles.
 

UPMan

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You can also set up a custom broadcast screen for frequency ranges you don't want to get hits on. Note that the scanner will still detect and count the hit, but will not tune to or open squelch on it. Such screened hits do make the time to determine no signal of interest for a band to be closer to 100 mS for that band (which, if you are in CC Pri mode, will result in a longer break in the audio than if there were no detectable signals).

The main benefits of this method over sweeping are:

1) Much faster acquisition of a target signal (100 mS vs up to several seconds).
2) Much faster release if there are no target signals (10 mS vs up to several seconds).
3) The ability to operate interleaved with scanning ("invisibly" in the case of models that have CC DND mode) without missing much, if any, scanning traffic (vs missing up to several seconds of scanning traffic).

The downside is that you only have the potential of getting one hit per CC band vs the ability to get multiple hits within a band for the sweep method.
 

rbm

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Has anyone used a preamp to increase Close Call range?

Something like this maybe? http://www.scannermaster.com/WRP_1300_Pre_Amplifier_p/28-531167.htm
I use several of the RF BAY amplifiers at the link below on my base antennas along with some others.
It's not unusual for me to get CC hits from mobile units a mile or more away. Air band hits at altitudes of 30,000+ feet.

If you want to see for yourself if the system is clean, you can listen to my online feed.
It currently is running on a BCT15. (I don't use CC on the scanner feed.)
Feed info is here: http://www.radioreference.com/forums/showpost.php?p=826960&postcount=6

Rich

Edit: I should add that one of these may be a little too much gain in a vehicle if you travel in RF rich environments.
Those times that I use a preamp while traveling, I use a Jim M-75 because I can vary the gain as needed.
Jim-M-75
http://www.radioworld.co.uk/~radio/catalog/scanner-preamp-p-5899.html?language=en
or here (more $$$)
http://www.scannermaster.com/Jim_M75_Pre_Amplifier_p/25-531151.htm

LNA-1000
10 – 1000MHz Low Noise Amplifier
http://www.rfbayinc.com/LNA/LNA-1000.pdf

They're a little cheaper if you buy them on eBay.
I've bought close to a dozen various amplifiers from him and they all performed as expected.
http://cgi.ebay.com/10-1000MHz-Low-...VQQcmdZViewItemQQ_trksidZp1638Q2em118Q2el1247

Their selection of Low Noise Amplifiers and the specs. are here.
http://www.rfbayinc.com/LNA.html
 
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benzrider2000

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RBM,

Thanks for the response. If I buy the Jim M75 preamp, can I really expect to get better Close Call hits? Is it really worth the $200?

Thanks.
 

rbm

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RBM,

Thanks for the response. If I buy the Jim M75 preamp, can I really expect to get better Close Call hits? Is it really worth the $200?

Thanks.
If you use the Jim M-75 preamp you really can expect to get more CC hits. With the caveat that if you are in an RF rich environment you will likely have interference problems which you can usually correct by backing the gain down.

Is it worth the $200, yes and no. Only you can be the judge of that.
However, if all of mine were taken out by lightning tomorrow and that was the only way I could get a replacement, I'd pay the $200. It probably wouldn't be worth that much to most people though.

You can get used ones cheaper on eBay at times. A few years ago the selling price (new) was $139-$159 in the U.S. and Canada and I bought two of them at those prices.

I bought a few (5) on eBay. The cheapest for $41.33 and the most expensive one for $75. Although I suspect that more people are aware of them now and there's more competition for them.

You can find them most often in the UK or Australia since they stopped selling them in the U.S. for quite a few years.

New, they sell for less in Europe than the U.S. Somewhere around $135 minus shipping.
Click for price in USD at the link below.
http://www.cbshop.com/shop2.asp?display=&brand=&name=Jim M75&cc=d&g=&sg=&soid=
and here:
http://www.haydon.info/38_scanner_accs.htm
http://www.hamradio.co.uk/acatalog/Accs_Pre-amps.html
http://www.nevadaradio.co.uk/acatalog/scanner-accessories.html
and at many other places.

I have multiple antenna systems and use one of them on each feedline as a master gain control. I have a pre-amp right at the base of every antenna and a Jim M-75 inside.

With my BCD996T's and BCT15's (except for my online feed) I keep CC DND on all the time. Not so on the BCD396T. I set a distinctive alert for CC hits. That's gotten my attention a few times when there was activity in my neighborhood that I otherwise may have missed.

With my BCD396T I only turn it on when I'm at an event or a specific location and want to find/verify active frequencies.
also..........
I use a mag-mount antenna on my vehicles and I often will connect a Jim M-75 and the BCD396T and let it log CC hits all day while my car is in a parking lot. It doesn't take very long to map out frequency usage that way.

Rich
 
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benzrider2000

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Rich,

I received my M75 yesterday and I have a couple of questions...

Is it compatible with digital frequencies?

Also, I have a buddy that tried it on his PSR500 and he scanned known freqs and didn't get any hits with the gain up or down... He took it off and put just his antenna on and got tons of hits. Do you know why this could be happening?

Also, where do you position the 3 position switches on the front?

Thanks.
 

wbwarnerb

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Rich,

I received my M75 yesterday and I have a couple of questions...

Is it compatible with digital frequencies?

Also, I have a buddy that tried it on his PSR500 and he scanned known freqs and didn't get any hits with the gain up or down... He took it off and put just his antenna on and got tons of hits. Do you know why this could be happening?

Also, where do you position the 3 position switches on the front?

Thanks.
I'm the buddy who was helping him out :)

So what I did... here in the office... i put the m-75 on my psr and scanned LA county (mostly digital frequencies) that I've entered. It scanned for over a min with not one hit (the M-75 was on). I turned the M-75 "off" (but it was still physically connected between teh scanner and the antenna) and still no hits.

thinking something was wrong, I removed the M-75 physically from the scanner, put the stock antenna on, and hundreds of hits.

There's a switch on the front of the M-75 that is labeled A, B and C. I tried A and C.

I didn't get the typical sensation of "overload" - it just seemed to nullify my scanner - even when the M-75 was off. Once it was disconected I could once again pick up all the stations (mostly digital) surrounding me.)

I also tried known frequencies that have descent activity... like this ham freq in LA: 147.435 It did get one transmission there... but when i removed the 75, there was a lot more activity it wasn't picking up.

one more thing, my ATT was off during the time of the test.
 
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rbm

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The amplifier will work equally well with any type of transmissions including digital.

The switch positions change the filtering on the amplifier.

A - passes 225-1500 MHz
B - passes 108-185 MHz
C - passes 24-2150 MHz (essentially no filter at all)

It helps to have a list of known, active frequencies to use for testing.

You can use NOAA weather frequencies, paging frequencies, etc., for testing purposes.

I'm assuming that you irnstalled a 9 volt battery and the red LED comes on when you turn the unit on.

You should be able to tune in a NOAA weather broadcast for a quick test. If you can receive more than one in your area, pick the weakest for testing purposes.

Then set the Freq. Range switch to 'B' just for this test. That should eliminate any overload from strong TV and FM broadcasts.

If the red LED is lit when you turn on the unit and you don't hear the NOAA broadcast there may be something wrong with the unit.

If that works and you're trying to hear an 800 MHz signal, you can change the switch to A or B. If you set it to A, it will filter out most of the frequencies below 225 MHz.
(I'm assuming that they didn't change the filter frequencies from what they are on my units.)

Rich
 
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benzrider2000

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Rich,

I really appreciate your help. I'll go through the test you mentioned.

Another question. The preamp has a -10 to +20 db gain. When you first turn on the preamp, is there more gain than the scanner has or does the preamp start gaining power at the 0db gain setting?

Also, if the preamp is turned off and still connected to your scanner, does it cut the antenna from your scanner or does the scanner still "see" the antenna?

Thanks,
Eric
 

rbm

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Rich,

I really appreciate your help. I'll go through the test you mentioned.

Another question. The preamp has a -10 to +20 db gain. When you first turn on the preamp, is there more gain than the scanner has or does the preamp start gaining power at the 0db gain setting?

Also, if the preamp is turned off and still connected to your scanner, does it cut the antenna from your scanner or does the scanner still "see" the antenna?

Thanks,
Eric
The gain setting is not all that precise, somewhere around the zero setting the gain 'should' be about equal to the scanner without the preamp. However, depending on the noise figure of the scanner, the 'system' noise figure should be better. (Assuming that the 2 dB noise figure of the preamp is better than that of the scanner.)

If you turn the preamp off, it isn't bypassed. You have to physically remove the unit.

By the way, I just did the NOAA frequency test with one of my PRO-95 handhelds with a rubber duck antenna.

Without the preamp I can receive two NOAA frequencies.
One strong and one about 60% quieting.

When I installed the Jim M-75 I could receive four NOAA frequencies.
Two full quieting and two about 50% quieting.

Rich
 
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rbm

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I guess it would be easier to let you hear the difference than try to explain it.

Here's an 8-second audio clip of the very weakest NOAA broadcast I can receive. (Made with Scanner Recorder.)
This is using a 2 meter vertical ham radio antenna.
That antenna has around 80' of feedline and NO preamp. The antenna is around 40' off the ground.

The first 4 seconds are without the Jim pre-amp installed. Then the last 4 seconds is with the Jim pre-amp set to a gain setting of around +5.

(I had to zip it. RR doesn't like .wav files)

Rich
 
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rbm

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And to be complete:

Here's a clip of the same NOAA broadcast using a Scantenna with an RF Bay, Inc. LNA-1000 pre-amp. right at the base of the antenna. ($69.99 on eBay)
http://www.rfbayinc.com/LNA/LNA-1000.pdf
A better pre-amp at ($149.99 is here.)
http://www.rfbayinc.com/LNA/LNA-1400.pdf
http://www.rfbayinc.com/LNA.html

Using this enclosure:
http://www.radioreference.com/forums/showpost.php?p=860180&postcount=5

The Scantenna is close to the same elevation and feedline length as the vertical antenna used for the previous clip.

The receiver is an Icom IC-R7000

The frequency is 162.500 MHz and the signal is S-5.

The adjacent frequency of 162.475 MHz is S-9+20dB
The adjacent frequency of 162.525 MHz is S-9

Using that antenna setup I can receive at least one station on every NOAA frequency.

Rich
 
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benzrider2000

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Rich,

You have been a very big help! I'm really seeing the difference when using the M-75. I haven't done too much testing on CC hits, but I'm getting better signal when using it.

I know you said you have a 996T and use the CC feature on it. Does the 996T also cut out every 2 seconds when it's monitoring for CC's like the 396T does?
 

rbm

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Rich,

You have been a very big help! I'm really seeing the difference when using the M-75. I haven't done too much testing on CC hits, but I'm getting better signal when using it.

I know you said you have a 996T and use the CC feature on it. Does the 996T also cut out every 2 seconds when it's monitoring for CC's like the 396T does?
I'm glad it's working for you.

On the BCD996T & BCT15, If you select CC DND (Close Call Do Not Disturb) it does NOT interrupt scanning like CC does on the BCD396T. Although some of the other functions (Priority, WX Priority) will. I really like the CC DND feature on those two models.

By the way, depending on the band you're interested in at a given time, the filter selection on the Jim M-75 can be a big help just by itself.

Rich
 
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