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

[jeffm77]

See I don't know about any of you guys but on my 436 the problem is I can do a limit search between 450 and 480 megahertz and have my 396xt searching the same band side by side using nothing only but the stock antennas on both radios the 396xt will find signal and the 436 just scans right past the same frequency that the 396xt just found so there is something wrong somewhere. I'm at work until 7 when I get home my tape is already there I order the copper Emi Shield tape off of Amazon I'm going to do the tape experiment and I'll report back my findings. I don't understand how some people's radios work just fine and others have the UHF issue I have two friends of mine locally that have the same radio and have no issues with theirs however two other friends of mine that don't live in Pennsylvania have the same radio and have the same static issue that I have with mine. I can scan a local DMR trunk system with my Whistler with no issues and when I scanned the same system with the 436 it skips Transmissions and doesn't pick up any of it

 

[KevinC]

I think there are other problems with some of the 436 scanners causing RX issues. As I mentioned in one of the DMR threads, my 536 consistently receives 2 bars more than my 436 when I attach them to the same external high gain antenna and monitor UHF DMR. If the 536 receives 4 bars the 436 will receive only 2 bars. So whatever issue is causing this 12 dB drop between the two scanners is likely not going to be fixed by shielding the battery cover. Shielding the battery cover might improve reception with an HT antenna on the 436. I still have not seen any data in this thread that really backs that up. Mostly just seeing anecdotal data, which is rather useless IMO. What I would like to see is a video showing terrible reception on UHF, especially DMR, with the battery door unshielded, then decent reception on same system with the door shielded. Not all 436's seem to have the same issues nor the same amount of issue. Some here seemed to be having better reception while others don't with this shielding experiment. I've never really noticed the hissing issue on UHF. My issue seems to be total deafness on UHF DMR when using an HT antenna.

Keep in mind I'm not a videographer...

https://youtu.be/RVWvf5ELnVI

https://youtu.be/s0F8iZWfbvU

 

[bravo14]

Keep in mind I'm not a videographer...
https://youtu.be/s0F8iZWfbvU

How do you get the info to show up in SCR Mode? I have the latest firmware.

 

[bearcat]

Did you go over or under the foam. Going under did not work for me

 

[jeffm77]

Bearcat, on the tape experiment, you must cover up the whole back, going over, not underneath the foam, correct?

 

[troymail]

IMPROVEMENT??????

Earlier, I had removed the foam and then place two layers of copper foil on the door... didn't see much change....

At Kevin's recommendation, I put the foam pad back under the foil and WHOA.... What a change! I am now hearing things I wasn't hearing at all before without standing on my head and holding the radio up with my feet.....

BIG BANG has arrived.

 

[bravo14]

Earlier, I had removed the foam and then place two layers of copper foil on the door... didn't see much change....

At Kevin's recommendation, I put the foam pad back under the foil and WHOA.... What a change! I am now hearing things I wasn't hearing at all before without standing on my head and holding the radio up with my feet.....

BIG BANG has arrived.

Did you take out the tape completely off the door and put back the foil? Or Let the tape on and just piece of foil around the foam pad?

 

[troymail]

Did you take out the tape completely off the door and put back the foil? Or Let the tape on and just piece of foil around the foam pad?

Right over it - foil is edge to edge on the flat part of the door

 

[snerd]

Enough, or more on the sides?

Wow! It doesn't downsize pics here! I'll get a smaller one.

 

[Jay911]

The positioning of the foam rubber now makes a difference in signal strength?

When are we going to concede there is voodoo magic going on inside this box?

 

[snerd]

The positioning of the foam rubber now makes a difference in signal strength?

When are we going to concede there is voodoo magic going on inside this box?

I found that standing on my left foot, with my right arm extended, while playing Stairway To Heaven on the stereo at volume 11, tended to optimize my reception.

 

[troymail]

The positioning of the foam rubber now makes a difference in signal strength?

Odd as it sounds, yes. Actually, the presence of the foam makes a huge difference - at least in my case.

 

[KevinC]

I found that standing on my left foot, with my right arm extended, while playing Stairway To Heaven on the stereo at volume 11, tended to optimize my reception.

Odd as it sounds, yes. Actually, the presence of the foam makes a huge difference - at least in my case.

I'm leaning towards it's foil actually touching the battery that makes the difference.

I can hold my door up to the batteries and still see the noise, as soon as it touches them it attenuates greatly.

I would do more testing along these lines, but my noise is all but gone so I'm happy.

 

[troymail]

I have 9 1/2' of copper foil tape available --

 

[jeffm77]

I have the copper tape on mine and am not seeing any difference.

 

[troymail]

I have the copper tape on mine and am not seeing any difference.

Gathering info...

Overtop of the foam pad? Mine did nothing when I removed the foam. When I returned it UNDER the foil, it made a big difference.

Were you having issues receiving 450-470 Mhz (DMR specifically) before? In my case, with only a few exceptions, I'd get UHF DMR reception but only if I was very close to a transmitter.

What brand batteries are you using? I use either Eneloops or Duracell NiMHs.

 

[KevinC]

Gathering info...

Overtop of the foam pad? Mine did nothing when I removed the foam. When I returned it UNDER the foil, it made a big difference.

Were you having issues receiving 450-470 Mhz (DMR specifically) before? In my case, with only a few exceptions, I'd get UHF DMR reception but only if I was very close to a transmitter.

What brand batteries are you using? I use either Eneloops or Duracell NiMHs.

Now he's the expert...

 

[jeffm77]

I put the copper tape over top of the foam and covered the whole back of the door.

 

[KevinC]

I put the copper tape over top of the foam and covered the whole back of the door.

Doing it just like this should work, nothing more, nothing less...

http://forums.radioreference.com/un...mprove-your-uhf-reception-10.html#post2616713

 

[troymail]

Now he's the expert...

I just train well.... slow, but well.

:lol: