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

[snerd]

Running Custom Search 450-469 I picked up 2 I haven't heard before. I would bet they're the Goodyear plant west of town, a good 10 miles from me here on the far east side. 0 to 1 bar and I hear them fine. Not scientific by any means, but I think it helped mine.

 

[darunimal]

.. I picked up 2 I haven't heard before..... 10 miles from me .. 0 to 1 bar and I hear them fine. Not scientific .., but I think it helped mine.

Awesome if we can see some more people (unlocking all of their local birdies) and checking this out for themselves, I won't have to make 436 effigies and sell them on ebay.

More reading material for those diagnosing and testing
http://forums.radioreference.com/uniden-tech-support/291445-rf-performance-feedback-436hp.html

http://forums.radioreference.com/un...nsitivity-test-had-come-out-eventually-5.html

 

[deadvolvo1]

Is it possible that the foil over the foam is actually coupling sufficiently to the negative battery terminals and acting as a counterpoise?

 

[Comp-100]

Someone could run a little metal strip or bare wire from the ground across the batteries and see if having that contact the metal tape sheild makes a difference.

 

[KC0KBC]

What I don't think has been mentioned is if anyone has tried grounding the shield tape to the radio's ground plane?

I agree. I'm a little surprised that this is making much difference at all without grounding the new shield. I plan to add the shield too, but would be interested in seeing some testing done with the updated door grounded.

I may use 3M 1345, which is tin-coated copper to facilitate soldering and impede corrosion (but it's pricey).

Edit: Another thought would be, maybe this works simply because it's grounding the battery cases together, and that's enough to provide a path to ground for this stray signal. It might be interesting to try wrapping a bare wire around the three batteries and repeating the SA tests without the battery door or with a door that hasn't been modified. I'm not equipped to perform such tests.

 

[AA6IO]

I have two 436HPs and one seems reasonably sensitive. Other one was less sensitive and have been debating about sending to Uniden to see what is going on. Received copper tape today from Amazon.
Put on back cover like Jay in post #214 of scanner with poor sensitivity, especially UHF. Thought someone had exchanged scanners. Came back to life with very nice signals. Have not done any quantitative tests, but qualitatively, just listening to it, seems to be "returned" fo life. Something going on with this shielding.
Will ltry on the "better sensitivity" 436HP tomorrow. Perhaps will have a "supersensitive" 436HP.
Thanks for the tip everyone. Grab your copper tape before Amazon runs out.

 

[bearcat]

Is it possible that the foil over the foam is actually coupling sufficiently to the negative battery terminals and acting as a counterpoise?

There is no phyical connection

 

[dsalomon]

Got my roll of 1" copper foil tape from Amazon yesterday and immediately applied it. I am happy with the results. I have not done any screen captures of side by side testing with / without the battery door, so nothing concrete to show, yet. However, I am seeing / hearing a discernible difference from listening with / without the battery compartment door on.

Now that I know improvements can be made with simple changes, I will look for more posts from others who have found other ways to improve upon this already excellent radio. I will also continue my own testing and tinkering and post any results I find.

73 - David, AG4F

 

[bearcat]

Got my roll of 1" copper foil tape from Amazon yesterday and immediately applied it. I am happy with the results. I have not done any screen captures of side by side testing with / without the battery door, so nothing concrete to show, yet. However, I am seeing / hearing a discernible difference from listening with / without the battery compartment door on.

Now that I know improvements can be made with simple changes, I will look for more posts from others who have found other ways to improve upon this already excellent radio. I will also continue my own testing and tinkering and post any results I find.

73 - David, AG4F

So far all positive results except for jeffm77 not bad

 

[bearcat]

Emi/rfi spray ?

I wonder how effective spray will be since the gap between the case and the battery would still exist. We do have one positive sprayer but he is not at liberty to give out details due to work rules

 

[troymail]

I wonder how effective spray will be since the gap between the case and the battery would still exist. We do have one positive sprayer but he is not at liberty to give out details due to work rules

Given this has proven to fix a pretty significant problem, it should be in Uniden's court to provide a real fix at this point.

My reception went from non-existent to actually working for UHF DMR systems as a result. Significant.

 

[IAmSixNine]

I did not have any luck testing this out.
I got 1inch wide copper foil tape https://www.amazon.com/gp/product/B018RDZ3HG/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1
applied it to my scanner and tested it out.
I have a station that comes in weak on my Hyetera radios and my scanner is on the border of picking it up.
454.575 is the freq and its a single channel DMR hospital security channel.
See the pic attached of my foil job on my battery door.
https://dl.dropboxusercontent.com/u/28210603/2016-07-27 13.04.04.jpg and
https://dl.dropboxusercontent.com/u/28210603/2016-07-27 13.04.12.jpg and my testing was done keeping the scanner in the same spot.
I would attach and detach the battery door between transmissions. I also tested with stock antenna and RS800mhz antenna. The best results i got were with it off using the RS800mhz antenna.
I also got the same results after i removed the foil and went back to a normal battery door.
So im guessing my scanner does not have the emissions issues coming from the battery door area.
https://dl.dropboxusercontent.com/u/28210603/2016-07-28 09.09.42.jpg
Im also on the 4th floor of an office building with an exterior window, not in the center of it. I also have the scanner on a stand so keeping it in the same spot as to try to keep the testing more accurate.

 

[troymail]

I'm curious if this is a manufacturing change... When did people acquire their radios and what serial numbers are we talking about?

Mine:
Purchased: April 2014
Serial: xxxx48000723
Comment: copper foil made a huge difference

 

[IAmSixNine]

My scanner is a second hand one. Picked it up about 9 months ago from a pawn shop selling it on ebay.
xxxz58001xxx
copper foil had no affect or just ever so slightly hindered it a tad bit. only tested on 454.575 dmr distant single channel.

 

[Jay911]

I won't be able to do any serious testing today as I'm getting buried at work. But it seemed like various DMR and analog signals in the 460 MHz range were improved on my commute... not sure how valid that is since my in-vehicle antenna connection is an Austin Spectra fender-mount.

My radio is 38001206 and I purchased in Feb 2014.

 

[troymail]

I won't be able to do any serious testing today as I'm getting buried at work. But it seemed like various DMR and analog signals in the 460 MHz range were improved on my commute... not sure how valid that is since my in-vehicle antenna connection is an Austin Spectra fender-mount.

My radio is 38001206 and I purchased in Feb 2014.

I think this is more about reception with a duck or similar on the radio itself getting interference from the battery compartment.

I typically got better results with an external antenna attached but now it seems like I'm getting better results WITH the stock antenna on the 436 (with 50 cents worth of copper shielding).

 

[SCPD]

I wonder how effective spray will be since the gap between the case and the battery would still exist. We do have one positive sprayer but he is not at liberty to give out details due to work rules

I'm a she, but that doesn't really matter.

Got a bit of good news, a colleague is going to let me borrow their personal spectrum analyzer (Signal Hound BB60C) for a few weeks. This is same model I used at work to confirm the measurements I took with the Keysight benchtop BSA.

This data I can release.

Any requests?

My plan is to take various readings, but I am open to suggestions. Know most don't have access to a SA so here is your chance....

Anne-britt

 

[bearcat]

I did not have any luck testing this out.
I got 1inch wide copper foil tape https://www.amazon.com/gp/product/B018RDZ3HG/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1
applied it to my scanner and tested it out.
I have a station that comes in weak on my Hyetera radios and my scanner is on the border of picking it up.
454.575 is the freq and its a single channel DMR hospital security channel.
See the pic attached of my foil job on my battery door.
https://dl.dropboxusercontent.com/u/28210603/2016-07-27 13.04.04.jpg and
https://dl.dropboxusercontent.com/u/28210603/2016-07-27 13.04.12.jpg and my testing was done keeping the scanner in the same spot.
I would attach and detach the battery door between transmissions. I also tested with stock antenna and RS800mhz antenna. The best results i got were with it off using the RS800mhz antenna.
I also got the same results after i removed the foil and went back to a normal battery door.
So im guessing my scanner does not have the emissions issues coming from the battery door area.
https://dl.dropboxusercontent.com/u/28210603/2016-07-28 09.09.42.jpg
Im also on the 4th floor of an office building with an exterior window, not in the center of it. I also have the scanner on a stand so keeping it in the same spot as to try to keep the testing more accurate.

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

 

[bearcat]

I'm a she, but that doesn't really matter.

Got a bit of good news, a colleague is going to let me borrow their personal spectrum analyzer (Signal Hound BB60C) for a few weeks. This is same model I used at work to confirm the measurements I took with the Keysight benchtop BSA.

This data I can release.

Any requests?

My plan is to take various readings, but I am open to suggestions. Know most don't have access to a SA so here is your chance....

Anne-britt

That was a typo i missed the s in front he. Lol. That is why i try to use poster most of the time. Thanks for your efforts

 

[bearcat]

I'm curious if this is a manufacturing change... When did people acquire their radios and what serial numbers are we talking about?

Mine:
Purchased: April 2014
Serial: xxxx48000723
Comment: copper foil made a huge difference

I knew this would come up. I purchased a new one before i made my original post and it did the same thing. My original radio is from the first shipment on release of the radio.

Xxx1145 feb 2014