BCD436HP/BCD536HP: UHF Reception Issues due to Noise from Battery Compartment

[IAmSixNine]

I think a larger sample size of freqs is need for a true test. Do a 450 - 470 custom search and take the door off and on. That will tell the tale

I put the tape on yesterday at work and monitored several channels ive already been listening to, also had one UHF amateur radio sound weaker. I can normally get it at home and last night nothing came in. I did some searching 450-460 and 481-485 and didnt notice much of a difference.
Thats why i parked it on the one channel i knew was in the 45x range that was a single channel and was on the borderline of receiving.
I honestly dont think my scanner is affected by the issues others are referring to.
So for now i think ill go back to monitoring and chime in if needed.

 

[bearcat]

I put the tape on yesterday at work and monitored several channels ive already been listening to, also had one UHF amateur radio sound weaker. I can normally get it at home and last night nothing came in. I did some searching 450-460 and 481-485 and didnt notice much of a difference.
Thats why i parked it on the one channel i knew was in the 45x range that was a single channel and was on the borderline of receiving.
I honestly dont think my scanner is affected by the issues others are referring to.
So for now i think ill go back to monitoring and chime in if needed.

Let us know if you find anything more. Did you put the copper over the foam?

 

[IAmSixNine]

Let us know if you find anything more. Did you put the copper over the foam?

Yup, put copper on top of the foam. Posted a few pics of my copper tape job in this posting.
http://forums.radioreference.com/un...mprove-your-uhf-reception-12.html#post2617022

Im satisfied my scanner has good UHF reception.
My Hytera PD682 and PD782 both were tuned to the 454.575 channel as well as my scanner and both Hytera radios picked up the signal with 1-2 bars each. My scanner barely picked up the signal and decoded it with 1 bar using normal battery door and RS800mhz antenna. With the tape on the door it would not pick up the signal. Stock antenna no signal with battery door normal, with tape and no door at all.
Based on the Hytera units getting 1-2 bars and my scanner picking it up fairly weak i have to conclude i dont have the UHF issues.
I can also pick up some UHF conventional PD channels that my Motorola radios in the same spot get a bit staticy with the scanner having more static before it drops off.

 

[bearcat]

Yup, put copper on top of the foam. Posted a few pics of my copper tape job in this posting.
http://forums.radioreference.com/un...mprove-your-uhf-reception-12.html#post2617022

Im satisfied my scanner has good UHF reception.
My Hytera PD682 and PD782 both were tuned to the 454.575 channel as well as my scanner and both Hytera radios picked up the signal with 1-2 bars each. My scanner barely picked up the signal and decoded it with 1 bar using normal battery door and RS800mhz antenna. With the tape on the door it would not pick up the signal. Stock antenna no signal with battery door normal, with tape and no door at all.
Based on the Hytera units getting 1-2 bars and my scanner picking it up fairly weak i have to conclude i dont have the UHF issues.
I can also pick up some UHF conventional PD channels that my Motorola radios in the same spot get a bit staticy with the scanner having more static before it drops off.

I guess I was not very clear in my previous post. This fix has little to so with what you can hear before the shielded case. It has more to do with what you are not hearing. Listening to freqs that you were receiving prior will not validate it is helping. I just do not want you to give up if it may be helping else where in 450-470

 

[IAmSixNine]

I guess I was not very clear in my previous post. This fix has little to so with what you can hear before the shielded case. It has more to do with what you are not hearing. Listening to freqs that you were receiving prior will not validate it is helping. I just do not want you to give up if it may be helping else where in 450-470

I dont see how i can benefit from this when i found through my own testing that on my device it doesnt help.
Again, i can listen to a distant / weak signal better with out the tape then i can with it.
So what good would it do for me to use it when its hindering my reception.
As stated in my original post a UHF amateur channel DMR was completely silent last night, that was the first time its been silent all night and last night was the only night i had the copper tape modified door. My hytera radios picked up the same channel fine so i know there was activity on it. So a 44x frequency was worse with tape and a 454.xxx frequency was worse with tape.
I get what your saying about it having less relevance with distant channels as the interference your referring to is causing noise on strong channels and preventing decoding on digital channels. However for me thats not the case. So yes i do believe we are on the same page but with my particular unit i dont get a benefit from tape.
But seeing as i have 12 yards of it and i only used a few inches i can put it back on.

 

[darunimal]

Okay, try 2plys without the fingers that lock into the case having any tape, you may have better result, idk. I believe you aren't receiving an improvement based on that. Try it out and let us know. Troymail did note improvement with 2 layers over a single application.

 

[KC0KBC]

Any requests?

Yes. Could you try a test where the battery door is removed entirely but the battery cases are all connected using a piece of bare wire or short ground strap? My theory is that the foil isn't really "shielding" anything, but rather providing a path to ground for this stray signal which is floating on the center battery.

 

[KevinC]

Interesting...

With the power being supplied via USB and no batteries I seem to have little to no issues. Installing the bottom battery seems to have no affect, removing it and installing the middle and I start having issues, leave it in and install the top battery and I lose the test signal completely.

Installing the top battery only seems to have little affect.

 

[troymail]

Okay, try 2plys without the fingers that lock into the case having any tape, you may have better result, idk. I believe you aren't receiving an improvement based on that. Try it out and let us know. Troymail did note improvement with 2 layers over a single application.

FWIW - I didn't see a difference with 1 layer so I added a second before realizing that you must leave the foam pad in place and foil over top of it (or maybe put the foam back after installing the foil). So, I'm not sure the 2nd layer made a difference.

 

[SCPD]

436hp Question of the day

Now the question is "will Uniden do this to the new BCD-436hp's?"
And will they send fixed battery covers to all the 436hp owners?
Cant wait to see if this pans out ....
I liked the 436HP interface but the 400mhz and airband is inexcuseable.

Anyone tell me if this fixed the airband?

 

[darunimal]

Yes. Could you try a test where the battery door is removed entirely but the battery cases are all connected using a piece of bare wire or short ground strap? My theory is that the foil isn't really "shielding" anything, but rather providing a path to ground for this stray signal which is floating on the center battery.

Do Not Ground Any of the Battery's contacts except the bottom right, without special precautions which I won't elaborate on, I'll repeat DO NOT GROUND your BATTERIES. Some person is going to burn up their scanner/car/house.

 

[darunimal]

FWIW - I didn't see a difference with 1 layer so I added a second before realizing that you must leave the foam pad in place and foil over top of it (or maybe put the foam back after installing the foil). So, I'm not sure the 2nd layer made a difference.

Okay I stand corrected, so the point still stands try 2 layers w/o the fingers being wrapped, especially if the refracted spurious injection is coming off of something inside the 2 boards inside. If you wrap the fingers you maybe making an antenna instead of an attenuator.

 

[bearcat]

Now the question is "will Uniden do this to the new BCD-436hp's?"
And will they send fixed battery covers to all the 436hp owners?
Cant wait to see if this pans out ....
I liked the 436HP interface but the 400mhz and airband is inexcuseable.

Anyone tell me if this fixed the airband?

Which aircraft band? Have you tried shielding the battery door? 400 comes to life with the door shielded. We will just needto wait and see if uniden says or does anything. Paul has not weighed in on this thread so far. What they do or don't do is out of our control. We are well on the way to solving it ourselves. I think???

 

[KC0KBC]

Do Not Ground Any of the Battery's contacts except the bottom right, without special precautions which I won't elaborate on, I'll repeat DO NOT GROUND your BATTERIES. Some person is going to burn up their scanner/car/house.

By connecting the CASES of the batteries? What do you think is happening when you apply conductive tape to the door, on top of the foam?

 

[KevinC]

By connecting the CASES of the batteries? What do you think is happening when you apply conductive tape to the door, on top of the foam?

You are bonding the cases then, not grounding.

 

[KC0KBC]

You are bonding the cases then, not grounding.

Correct. I don't remember saying "grounding." I didn't want to use the term "bonding" because some may take that to mean a permanent modification to the batteries themselves, which of course no one should attempt.

 

[KevinC]

Yes. Could you try a test where the battery door is removed entirely but the battery cases are all connected using a piece of bare wire or short ground strap? My theory is that the foil isn't really "shielding" anything, but rather providing a path to ground for this stray signal which is floating on the center battery.

Correct. I don't remember saying "grounding."

Ok, you said "path to ground".

 

[KC0KBC]

The point is, everyone is convinced (and I don't dispute) that the stray signal is on the center battery, and not the others. If that's true, what's the difference with the other two batteries? If there is no signal on them, why not connect/short/bond/whatever you want to split hairs on, the cases together, so that however the outer batteries are eliminating the signal can be shared by the center battery? Because IMO that's all you're doing with the tape, otherwise the people who put the foil under the foam would be seeing the same results.

 

[SCPD]

Tried this with my Whistler TRX1,works better too! Thanks!
DMR is better,Airband is strong,my 440 noise went away,I hear new frequencies I never heard from before,it works for sure.
I used foil.LOL!(i probably will change it to copper tape.

 

[IAmSixNine]

Adding a second layer this time yielded the same results for me. No improvement. Sorry i couldnt be of any additional help. I guess this only points out that if the scanner doesnt have the noise coming from the battery compartment then adding tape will not help it.
I also saw no difference in a P25 system on 700mhz, no differnece on a type 2 trunking system in 800mhz. From a technical stand point id love to know whats so different about my scanner vs the ones that do have the issue.
I took pics of both my battery doors from the first attempt and todays dual layer attempt.

EDIT if it matters im using Powerex batteries in my scanner but all my testing was done with it plugged into a power supply.
But to eliminate that once or twice i did unplug it and saw no difference.