BCT-8 Garbled Audio in Trunking mode--only

[ka3jjz]

It looks like all it takes to remedy this condition is the "fix" that is outlined in homer545's posting. I just did that to my BCT-8...and BINGO....the audio is now clear and it stops on Trunked Transmissions as it did before..and just as my other two BCT-8's do.

Step-by-Step Directions....

Remove power from the scanner. Remove the 4 phillips head screws that are found on the sides of the bottom cover. Carefully pull off the bottom cover...it might be tight and there are wires to the speaker that you need to be aware of...so take it easy..

Locate a small tuneable coil that is close to the center of the circuit board. It is silver in color and about 1/4" square. Examine the top and you will see the 'slug' with a small screwdriver slot in it. For 'insurance' purposes, mark the exact location of the slot...just in case you need to reposition it if you screw up. (Ask me how I know to do this....!!)

At this point you might want to position the scanner so that you can re-attach the power cord and be able to put the bottom cover back to the point where it might be close to its original position. You might find that when you do this, the scanner will work as when new....or...you might not. This step is just a bit of 'experimenting' and might give you an idea as to how far out of alignment it is.

Now...for the actual 'surgery'...with a small screwdriver, turn the slug in the coil 'Clockwise' a very small amount ! In my case, it was almost the smallest amount that I could move it...and still be able to say that I had indeed adjusted it. Now...attach the power cord again...and give it a try. You should hear a big improvement...this might depend on how far out of adjustment it was. You may want to give that slug another slight tweak...or not. The 2mm movement that was mentioned in the preceeding post is a good guide...I don't think I went that far....but the change was immediate.

My Wild A** Guess about this is that some of the components (a capacitor most likely) in the tuned circuit has changed value over the years...with time, heat, cold, etc. and has allowed that tuned circuit to become 'detuned'.... Since I am guessing (again!)...that your BCT-8 was working fine for a long time and then over a period of a few months, it got more and more flaky...that would mean that only a tiny bit of tweaking is going to be all that is needed to bring it back to 100%..

Before reattaching the bottom cover, let it warm up for a half hour...listen to the audio...bask in your new success, give a big THANKS to Homer545...then remove power, replace the bottom...and SCAN AWAY!!

I am sending a stack of Virtual $50 bills to Homer545 for this tip....and if it works for you, please do the same...!!!

Into the wiki this goes -- there seems to be a number of folks with BCT8s - surprising since it's such an old radio

Mike

 

[Jethro32]

We have a bunch floating around in my firehouse. And as old as it is I was surprised Uniden had a rebanding update for it. Thats going to keep them around even longer. I wish there was a way to update the 780xlt's

 

[ac4jx]

DaveIN.... I fail to see what you are getting at with your question... IF you read my posts, you should see that the BCT-8's ALL have worked fine for a long time, and then two of them...and now the third, have developed a problem in the Trunking audio... Uniden / Bearcat has fixed two of them...and now those two work as intended. I fail to see what could be learned by whether or not the Search works...as that would NOT fix my problem. IF I had been doing anything wrong in the setup or programming, I think that Bearcat would have told me so...and...I don't think they would have worked correctly for such a long time...

And, yes....it does fail the same way in Search...but...I could care less about that...as I want it to work right in Scan....which is how I use it... Thanks for your efforts...

kskama: Thanks for your information, I also have this problem & have no solutions , but certainly glad to hear that it wasn't just me. Have you ever noticed these forums are nearly useless? There's always some idio telling you ""should"" work. Well if it worked, I wouldn't be in this room would I? lol
I'm sending mine to the factory as well, and a radio tech at the law enforcement agency where I work is looking into my 2nd BCT8. If I get a "specific" answer, I'll relay it to you....and avoid the psychobabble that the rest of these morons like to place on these forums.

 

[ka3jjz]

If you look at message 21 of this thread you will find a little procedure that may cure this problem. It is also in our wiki

best regards..Mike

 

[kskarma]

Just a follow up to all of this... As my first post mentioned, I have 3 BCT-8s that are all about 5-8 years old now. One is in my van, the other two are inside. Since I got the great hint from Homer545, I have applied this 'fix' to all of them at one time or another... It looks like tweaking this coil is the ONLY thing that can be a 'User Adjustment", so it's lucky that it works for the only problem I have ever had on my BCT-8s.

Good to see that this went to Wiki...I am sure many others have had the same problem.

 

[ac4jx]

Ke4ksm

Let me ask you, have you actually READ my postings?? This has happened before...to two other BCT-8's... And...currently those two are working perfectly fine after having been serviced by Bearcat. And...while some of the radio users here DO use APCO...(i.e. digital)...those are not the freqs. that I am having this problem with...(with just this ONE BCT-8)..the others work fine...as does my BR-330T.

My many years of servicing main frame computers for a BIG company (guess which one!) would suggest to me that if you have 4 units of any kind...and three of them work just fine...and one does not...that the problem just MIGHT be with that one unit....!!!

I am NOT a novice in this...have had many scanners over the years (about 35 years and as many scanners!), I currently have about a dozen running...a few in Trunking...a few that do not Trunk.

This just reminds me a bit of the problem that used to happen to the Bearcat 250 scanners....after a few years of service..when they would develop "Bearcat Disease"...a problem with the CPU chip I think... They would get to the point where they were unable to store freqs...or scan..etc. It was only repairable by Uniden and I think I had or knew of 4- 250s with this problem.

AWESOME ! KSKAMA , That was the 1st specific data in my life-time ever posted on one of these normally useless forums, that WORKED!!!
I let the BCT8 run for over an hour, and audio is fantastic, both in normal scan mode, and "trunked" mode!
And yes, I get so frustrated at brain-dead people like the previous post who questioned if your system had switched to APCO-25? Damn, if i'm that brain-dead, the scanner should not be taken apart!!
Thank you! Not to ramble, but where my radio would hose up: Switching from the stored EDACS groups, to the "SEARCH" MODE, while remaining in the "trunked" mode. At this point the audio would garble, and switching back to "trunked" scan mode would NOT improve the audio.
Also thought it was heat related here in Florida, with scanner mounted in my truck. That was incorrect !
Cool, or Hot....audio sucked! Until turning that coil just a tiny bit.
I've posted rare fixes for radios, but ONLY when absolutely certain I knew what I was talking about...most of these people just "type" to be typing. lol
Thanks again: KE4KSM 911 Dispatcher near Orlando, Florida

 

[ac4jx]

p.s. As KSKARMA previously advised, only turn that coil 2mm or less, or you're in a world of trouble!
My BCTB was placed on an RF techs bench at the Law Enforcement Agency where I work (With a service monitor attached)..and moving that coil causes "major" deviations to the receive frequency.
Mark the spot on the coil...or you'll own a BCT8 boat anchor. 73's

 

[ac4jx]

Ke4ksm

DaveIN.... I fail to see what you are getting at with your question... IF you read my posts, you should see that the BCT-8's ALL have worked fine for a long time, and then two of them...and now the third, have developed a problem in the Trunking audio... Uniden / Bearcat has fixed two of them...and now those two work as intended. I fail to see what could be learned by whether or not the Search works...as that would NOT fix my problem. IF I had been doing anything wrong in the setup or programming, I think that Bearcat would have told me so...and...I don't think they would have worked correctly for such a long time...

And, yes....it does fail the same way in Search...but...I could care less about that...as I want it to work right in Scan....which is how I use it... Thanks for your efforts...

OMG: I just saw the post from DAVEIN......He is the reason I despise these forums!!
Thanks again KSAMA for a clear, concise , fix to a given problem, minus the psycho-babble.
My BCTB sounds great again.
73's

 

[ac4jx]

Without a service manual you can just guess, but it does sound like a filter problem. It would be odd however to just have the problem on the trunked receive only, unless a different set of filters are used for the trunked mode. Do you load the radios using external software? Is this a Motorola or EDACS trunked system type? If EDACS I'd make sure the frequencies are entered correctly. If Motorola, I'd use the Control Channel only setting fro TrunkTracking.

Does this happen when using the Highway Patrol or Police search bank as in, does it sound garbled on a Motorola trunked system when the radio tracks a Motorola system in the search bank mode?

DavIn: Must work for the Federal Government!! lol Still talking this problem to death!
thanks to Mike....My BCT8 has been working like a charm for 3 days...while DAVIN,, is still talking about it.
lol

 

[ac4jx]

And it may be odd as hell for the problem to occur only in Trunking mode...but that's "exactly" what the last 15 posts have said!! GEEEEZ
Don't know why!!! But tune the tiny slot (as mike suggested) and you'll save yourself a lot of talking.

 

[bge1234]

I've been having the same problem and almost bought a replacement scanner (not realizing that it would be cheaper to send it in for service) when I thought I'd post on here first. Glad I did! Thanks everyone.

 

[talk89]

i have a BCT8 uinden scanner my countywent to trunked radio systems the type is motorole type 2 smart zone my scanner came witch this software version 1.01 are any new version will this up grade to trunked thank

 

[bge1234]

I think you're asking if you need any software upgrades to use the BCT8 in trunked mode, and the answer is no. The only reason you might need to upgrade is if an older version didn't support trunking, but I'm pretty sure the BCT8 always has.

 

[ka3jjz]

There is a firmware upgrade for rebanding, but that's about it. It seems a LOT of people have problems trying to program the BCT8 for trunking - this should be helpful (all links are in blue)

Programming the BCT-8 - The RadioReference Wiki

It would be helpful to know what system you are trying to program - that way we can all see what you're trying to hear - note that the BCT8 can't handle a P25 digital system - you need a digital trunktracker for that...

best regards..Mike

 

[dixie729]

I found the solution to this problem.

Take the bottom cover off the radio. On the bottom circuit board of the radio directly under the speaker magnet there is a varible coil. Take a small flathead screwdriver and turn the coil about 2 millimeters clockwise. Boom......you will have clear audio in trunking mode once again.

I have done this and it corrected the problem with my BCT8. I read on a couple of other forums that the magnet in the speaker is causing the inductance in the coil to go out of wack.

Let me know if this works for you.

Thanks for the DIY tip. My BCT8 was acking up the same way.

 

[ka3jjz]

For future reference, the procedure for correcting the garbled audio has been captured in our wiki for some time now (all links are in blue)

Correcting the Garbled Audio when Trunking with the BCT8 - The RadioReference Wiki

best regards.....Mike

 

[ac4jx]

To KSKARMA

Cutting thru all the B.S. . Remove the top cover of the radio, & there is a black "pot" with a slot in it.
I took a plastic screw-driver and (with control channel tuned in) turned the pot very slightly & it solved my distorted audio problem.
I was advised of this "fix" last year by an RR memer for my BCT-8 which sounded as if it was off frequency.
He advised me to "BE SURE" to mark the space with a pencil so you can return to original spot if needed.
It worked so well, I mounted the BCT-8 in the dash of my truck & it works great. (Trunking & all!)
Always amazed at the B.S people type on a subject when they have no idea what they're talking about.
I've performed this fix on the BCT-8 , which was so hosed up it couldn't even follow the talk groups.
And it looks pretty snazzy in the dash!!!