Date   

Re: BCT15X Sensitivity

Leslie Polt
 

I reprogrammed using ProScan, no attenuation either global or by system. I am avoiding anything that would invalidate the warranty. I propose to return it to the vendor for credit or exchange. 
Les, K3JTP


Re: BCT15X Sensitivity

Terry Copeland
 


Re: Looking for Suggestions

thomas roth
 

Just a thought...

They look like they just have smoke/soot damage. No obvious evidence of Fire or water damage. Have you tried cleaning them up, trying a power up?

good luck either way...

@.02


Re: BCT15X Sensitivity

David O'Banion
 

The 15X has both global and system attenuation.    
Check to see if that function has been activated in any way.   

David    
KJ6QKV   


On Sunday, December 12, 2021, 08:47:08 AM PST, Leslie Polt <ljpolt@...> wrote:


Interim Report: I tried different multicoupler ports and even the discone feeding 15X directly; as expected, the same results. A signal must be at least S7 on the ICOMs in order to break minimum squelch on the Uniden, and then it's received weakly until it is an S8 or 9 signal on the ICOMs. Interestingly, the 15X "S Meter" shows 5 bars on any signal strong enough to break squelch, so it doesn't seem to serve any purpose. The Uniden specs. indicate AM sensitivity  at .3 mV, whereas the ICOM specs are not better than 1.6 mV (the R7100), so I would expect more from the 15X.  On a lark, I compared the reception of the 15X with a handheld BC125AT/Diamond RH77 whip sitting on the desk, and they received about the same. I would expect far better reception with a desktop scanner and attic discone configuration. With both the Close Call and attenuation features disabled, is there any other setting on the 15X that could be degrading the signal? I have several Uniden handhelds (analog and digital) including the BCD436/536 twins and have been very pleased with them, so this is the first time I've experienced questionable performance in a Uniden.
Les Polt, Esq.
K3JTP


Re: BCT15X Sensitivity

GM7BNF
 

Les
Crack the top case off, check the solder joint of the centre of the small piece of coax between the pcb and rear case mounted bnc socket. I have over the years found 3 whereby it was not soldered properly. This resulted in intermittent rx and crackling.

Go to the other end where its on the pcb, check the silver braid is either soldered or firmly crimped down too.

There was also a small batch that they had to solder a piece tinned wire from the bnc through to the joint with the coax centre because they had used the wrong sized crimp at the external pin centre hole of the female bulkhead mounted socket.

Mike de gm7bnf@...



On 12 December 2021, at 18:22, Leslie Polt <ljpolt@...> wrote:


A good point; didn't consider it, since I don't have airbands programmed into the 536 (using it for local P25 Phase 1 public service). Will program in a conventional airband system and conduct an A-B comparison since the discone feeds both.  
Les


Re: BCT15X Sensitivity

GM7BNF
 

Les
Crack the top case off, check the solder joint of the centre of the small piece of coax between the pcb and rear case mounted bnc socket. I have over the years found 3 whereby it was not soldered properly. This resulted in intermittent rx and crackling.

Go to the other end where its on the pcb, check the silver braid is either soldered or firmly crimped down too.

There was also a small batch that they had to solder a piece tinned wire from the bnc through to the joint with the coax centre because they had used the wrong sized crimp at the external pin centre hole of the female bulkhead mounted socket.

Mike de gm7bnf@...

 

 

From: main@Uniden.groups.io <main@Uniden.groups.io> On Behalf Of Leslie Polt
Sent: 12 December 2021 18:22
To: main@Uniden.groups.io
Subject: Re: [Uniden] BCT15X Sensitivity

 

A good point; didn't consider it, since I don't have airbands programmed into the 536 (using it for local P25 Phase 1 public service). Will program in a conventional airband system and conduct an A-B comparison since the discone feeds both.  
Les


Re: BCT15X Sensitivity

Dewey
 

"Range" has nothing to do with actual reception, so setting it one way for conventional reception verses a different setting for trunked reception is irrelevant.  What "Range" does is determines which Systems/Favorites will be loaded for scanning based on if the range setting reaches the radius of what is being monitored.  If the range is not set far enough for the BCD's/SDS's logic to reach a radius of what you want to monitor, that will not be loaded into memory.  Using BWI as a theoretical example, if all of the systems at BWI had a radius ring of 5 miles, then the scanner's range setting would have to be enough to reach within 5 miles of BWI (if not already inside of the 5 mile radius) from where the scanner is located based on it's current lat/long coordinates or nothing at BWI would be loaded for scanning.  It does not mean that the scanner cannot receive BWI, just that it will not load and subsequently look for BWI.

Dewey


On Sun, Dec 12, 2021 at 5:02 PM Leslie Polt <ljpolt@...> wrote:
I conducted an A-B test with the BCD536, which won (although even that scanner does not pick up the BWI ATC the ICOMs receive). Interestingly, both Unidens had the same limited reception until I discovered that the BCD536 "range" had not been set to max., which should be the correct setting for conventional systems. The 15X does not have that feature, and the Close Call was disabled.  Thank you all for your suggestions; it is gratifying to see so many active and helpful participants on this Group.
Les, K3JTP


Re: BCT15X Sensitivity

Leslie Polt
 

I conducted an A-B test with the BCD536, which won (although even that scanner does not pick up the BWI ATC the ICOMs receive). Interestingly, both Unidens had the same limited reception until I discovered that the BCD536 "range" had not been set to max., which should be the correct setting for conventional systems. The 15X does not have that feature, and the Close Call was disabled.  Thank you all for your suggestions; it is gratifying to see so many active and helpful participants on this Group.
Les, K3JTP


Re: BCT15X Sensitivity

Rick NK7I
 

Comparing a whip on a desk to an antenna in the attic is not necessarily a valid test.  I have Hardy board siding, which proves to be an excellent RF shield (it's made of concrete, in part).  It's also possible that the losses from the attic are not equal to the losses on the desk (through walls, next to noise sources).

Side by side, sharing the same whip antenna (a tee connector) would be a valid test.  Even moving one whip or being slightly different could place that antenna in a null; make them equal.

As mentioned prior, the arrangement of your system may give the 15x too much signal, overloading it (counterproductive).  A stray voltage may have leaked out from the attic amp causing damage too (if not DC blocked adequately).

The S meter, is useless nowadays, it's a relative meter UNLESS one has taken the time to calibrate it; it's doubtful that Icom did more than a gross calibration (to meet spec, ship it).  As you found, the 15X meter, has no value or usefulness.

After a fair comparison, it's entirely possible that you've lost an element in the 15x making it more deaf, but to be sure, as you are hearing a station, wiggle the antenna connector too and note any differences (one of the weaker points of any radio, easily abused).  Ditto any antenna connection on that feed (you've done part of that by switching ports) and validate the integrity of the cable (chewed on by tiny livestock?).

It may be time for it to be serviced; but when you send it in, try to document what you noted and tested (comparative tests, which band/s tested, types of signals used for the test [AM/NFM/P25], not "it doesn't hear').  You may have a weak or failed amp circuit (blown part or out of tolerance) or it may simply be grossly out of alignment for another reason.  It can happen on new radios or old.

GL es 73,
Rick NK7I


On 12/12/2021 8:43 AM, Leslie Polt wrote:

Interim Report: I tried different multicoupler ports and even the discone feeding 15X directly; as expected, the same results. A signal must be at least S7 on the ICOMs in order to break minimum squelch on the Uniden, and then it's received weakly until it is an S8 or 9 signal on the ICOMs. Interestingly, the 15X "S Meter" shows 5 bars on any signal strong enough to break squelch, so it doesn't seem to serve any purpose. The Uniden specs. indicate AM sensitivity  at .3 mV, whereas the ICOM specs are not better than 1.6 mV (the R7100), so I would expect more from the 15X.  On a lark, I compared the reception of the 15X with a handheld BC125AT/Diamond RH77 whip sitting on the desk, and they received about the same. I would expect far better reception with a desktop scanner and attic discone configuration. With both the Close Call and attenuation features disabled, is there any other setting on the 15X that could be degrading the signal? I have several Uniden handhelds (analog and digital) including the BCD436/536 twins and have been very pleased with them, so this is the first time I've experienced questionable performance in a Uniden.
Les Polt, Esq.
K3JTP


Re: BCT15X Sensitivity

Leslie Polt
 

A good point; didn't consider it, since I don't have airbands programmed into the 536 (using it for local P25 Phase 1 public service). Will program in a conventional airband system and conduct an A-B comparison since the discone feeds both.  
Les


Re: BCT15X Sensitivity

Joe M.
 

Obvious question: How does the 15 compare to the 536?

If there is much of a difference, I
would say there is an issue with the 15.

S-meters, while they at one time were reliable indicators (pun intended), are largely useless as manufacturers make them more sensitive to make the signal appear stronger than it really is.

But an apples-to-apples (Uniden-to-Uniden) comparison seems in order.

Joe M.

On 12/12/2021 11:43 AM, Leslie Polt wrote:
Interim Report: I tried different multicoupler ports and even the
discone feeding 15X directly; as expected, the same results. A signal
must be at least S7 on the ICOMs in order to break minimum squelch on
the Uniden, and then it's received weakly until it is an S8 or 9 signal
on the ICOMs. Interestingly, the 15X "S Meter" shows 5 bars on */any/*
signal strong enough to break squelch, so it doesn't seem to serve any
purpose. The Uniden specs. indicate AM sensitivity at .3 mV, whereas
the ICOM specs are not better than 1.6 mV (the R7100), so I would expect
more from the 15X. On a lark, I compared the reception of the 15X with
a handheld BC125AT/Diamond RH77 whip sitting on the desk, and they
received about the same. I would expect far better reception with a
desktop scanner and attic discone configuration. With both the Close
Call and attenuation features disabled, is there any other setting on
the 15X that could be degrading the signal? I have several Uniden
handhelds (analog and digital) including the BCD436/536 twins and have
been very pleased with them, so this is the first time I've experienced
questionable performance in a Uniden.
Les Polt, Esq.
K3JTP


Re: BCT15X Sensitivity

Leslie Polt
 

Interim Report: I tried different multicoupler ports and even the discone feeding 15X directly; as expected, the same results. A signal must be at least S7 on the ICOMs in order to break minimum squelch on the Uniden, and then it's received weakly until it is an S8 or 9 signal on the ICOMs. Interestingly, the 15X "S Meter" shows 5 bars on any signal strong enough to break squelch, so it doesn't seem to serve any purpose. The Uniden specs. indicate AM sensitivity  at .3 mV, whereas the ICOM specs are not better than 1.6 mV (the R7100), so I would expect more from the 15X.  On a lark, I compared the reception of the 15X with a handheld BC125AT/Diamond RH77 whip sitting on the desk, and they received about the same. I would expect far better reception with a desktop scanner and attic discone configuration. With both the Close Call and attenuation features disabled, is there any other setting on the 15X that could be degrading the signal? I have several Uniden handhelds (analog and digital) including the BCD436/536 twins and have been very pleased with them, so this is the first time I've experienced questionable performance in a Uniden.
Les Polt, Esq.
K3JTP


Re: BCT15X Sensitivity

Don
 

*Hi,


I have about 5 different units covering several frequency ranges of the Stridesberg Engineering Multicouplers for many years. There are non-powered or 12vdc powered versions. They produce the same signal level at each port for the powered units. Never have had a problem. Of course these are not just el cheapo rf amps. **
**
**At one time I had thought I would need/like to have a amp/preamp at the antenna(s). I discovered that it is not necessary with the gain of these Multicouplers. In fact an amp on the mast will overdrive the Multicoupler and of course cause problems.**
**
**Anyway, the problem can only be something in the rx, a broken antenna connection in the rx, a bad cable/connector, a bad port on the Multicoupler.**
**
**Hope he reports back. Should be simple to sort out in a couple of minutes.**
**
**Cheers,

Don
*

On 11-Dec-21 02:18, Matt Levin via groups.io wrote:
You may want to try a LNA to boost the signal level.  Each splitter device connected  attenuates the signal level.

Matt (via iPhone)


On Dec 10, 2021, at 12:49 PM, GM7BNF via groups.io <gm7bnf@...> wrote:



This mulicoupler, is it buffered by each having an built in attenuator? If not it could be an input impeadance/loading issue.

Try the discone direct to the radio first, then comeback.

Mike



On 10 December 2021, at 13:49, Leslie Polt <ljpolt@...> wrote:


This venerable analog-only model is still being offered new, and I recently purchased NIB from reputable electronics retailer. Primarily for civil/mil airbands. My attic discone feeds the 15X and 3  ICOM receivers (7100, 8500, 8600) through a multicoupler, so all are receiving the same signal. 15 miles from BWI the ICOMs clearly pick up transmissions that the 15X does not hear; even some controllers are breaking squelch with S-5 signals on the ICOMs, the Uniden hears nothing. The same with many aircraft comms; parking all receivers on the same freq. the ICOM misses what the others hear. Close Call is disabled and there is 0 attenuation. Am I overlooking another setting? Using ProScan. Thanks.
Les Polt
Towson, MD.
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Re: BCT15X Sensitivity

Walter Rymarczyk
 

I have a Stridsberg multicoupler, it’s amplified.  I find my 536 works better with the supplied whip antenna than with the discone on the multicoupler.  I think the multicoupler overloads the already sensitive 536.  It works well with my Icom 8500 though.
Walt

Walter Rymarczyk
2650 N Lakeview Ave No 1407
Chicago, IL 60614

On Dec 10, 2021, at 1:49 PM, GM7BNF via groups.io <gm7bnf@...> wrote:



This mulicoupler, is it buffered by each having an built in attenuator? If not it could be an input impeadance/loading issue.

Try the discone direct to the radio first, then comeback.

Mike



On 10 December 2021, at 13:49, Leslie Polt <ljpolt@...> wrote:


This venerable analog-only model is still being offered new, and I recently purchased NIB from reputable electronics retailer. Primarily for civil/mil airbands. My attic discone feeds the 15X and 3  ICOM receivers (7100, 8500, 8600) through a multicoupler, so all are receiving the same signal. 15 miles from BWI the ICOMs clearly pick up transmissions that the 15X does not hear; even some controllers are breaking squelch with S-5 signals on the ICOMs, the Uniden hears nothing. The same with many aircraft comms; parking all receivers on the same freq. the ICOM misses what the others hear. Close Call is disabled and there is 0 attenuation. Am I overlooking another setting? Using ProScan. Thanks.
Les Polt
Towson, MD.


Re: BCT15X Sensitivity

Rich
 

well, if you have attached the antenna directly to the radio (eliminating the multi coupler and the other radios) amd reception did not improve would that not point to the radio being the likely problem?


Re: BCT15X Sensitivity

Leslie Polt
 

 No difference trying other output ports on the multicoupler. Unlike a signal splitter, an active multicoupler provides uniform amplification and isolation of all output ports to neutralize signal loss due to a split. Over the weekend I will conduct other A-B comparisons, and report back. Thank you, all.
Les


Re: BCT15X Sensitivity

GM7BNF
 

Said this 3 times now….but we get no result.

 

mike

 

From: main@Uniden.groups.io <main@Uniden.groups.io> On Behalf Of Rich
Sent: 11 December 2021 01:59
To: main@Uniden.groups.io
Subject: Re: [Uniden] BCT15X Sensitivity

 

why not couple the 15X directly to the antenna and see if reception improves?


Re: BCT15X Sensitivity

Matt Levin
 

You may want to try a LNA to boost the signal level.  Each splitter device connected  attenuates the signal level. 

Matt (via iPhone)


On Dec 10, 2021, at 12:49 PM, GM7BNF via groups.io <gm7bnf@...> wrote:



This mulicoupler, is it buffered by each having an built in attenuator? If not it could be an input impeadance/loading issue.

Try the discone direct to the radio first, then comeback.

Mike



On 10 December 2021, at 13:49, Leslie Polt <ljpolt@...> wrote:


This venerable analog-only model is still being offered new, and I recently purchased NIB from reputable electronics retailer. Primarily for civil/mil airbands. My attic discone feeds the 15X and 3  ICOM receivers (7100, 8500, 8600) through a multicoupler, so all are receiving the same signal. 15 miles from BWI the ICOMs clearly pick up transmissions that the 15X does not hear; even some controllers are breaking squelch with S-5 signals on the ICOMs, the Uniden hears nothing. The same with many aircraft comms; parking all receivers on the same freq. the ICOM misses what the others hear. Close Call is disabled and there is 0 attenuation. Am I overlooking another setting? Using ProScan. Thanks.
Les Polt
Towson, MD.


Re: Looking for Suggestions

Michael
 

First of all, sorry about the fire. I hope everyone in your family, including pets, are OK. I would stay with the 536 or upgrade to the latest technology, the SDS-200.

Mike


Re: Looking for Suggestions

Joel Kahn
 

SDS200's

Joel R Kahn





On Friday, December 10, 2021, 05:01:03 PM EST, Tim Ferguson <tferg53@...> wrote:


Looking for suggestions on replacing two BCD536HP scanners that took the heat in a recent fire?  


Tim

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