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

[W2SJW]

I got some tape from nosoup4u today & put 2 layers down on my 436. Here in the shack near my PC, I was unable to decode DMR from the site 3 miles up the hill from here.

I've been monitoring for the last hour & continue to get totally clean decode of every transmission from that tower on only 2 bars of signal using my new 3" stubby BNC antenna.

I'm impressed!

 

[cellphone]

Is it possible that the foil/copper on the battery cover is creating a ground plane for the antenna? In the past I recall a post that mentioned running a wire from the ground ring of the earphone jack to create a ground plane that significantly increased performance.

 

[Comp-100]

Is it possible that the foil/copper on the battery cover is creating a ground plane for the antenna? In the past I recall a post that mentioned running a wire from the ground ring of the earphone jack to create a ground plane that significantly increased performance.

The testing so far seems to indicate it is suppressing some type of fairly wideband noise rather than increasing effectiveness of the antenna system. DC/DC Converter noise might be a possibility or some data buss, even internal to the cpu, somehow getting into some place that is desensitizing the receiver.

Now there is one person saying this is also helping a totally different scanner....

 

[snerd]

Are the extra layers of tape just for creating a tighter fit of the door-to-batteries? Or is it helping in the reflection of the spurious signal?

 

[ur20v]

I got my copper tape today from Amazon. Five minutes later I had my battery cover done. Since I have a discone at 25' at the shop, I decided to wait until I got home to test it out. I can say without a doubt the copper foil on the inside of the battery cover works to improve reception with the stock antenna! I'm hearing certain signals and systems that I would previously only hear with the outdoor antenna, and the local repeaters that I could copy are coming in completely noise free. What an improvement! Now I just need to figure out what to do with the remaining 9'9" of 2" wide copper tape ��

 

[ur20v]

Oh, and I carefully removed the foam and put it back in place after putting the copper down, and only used 1 layer of the copper tape. A massive improvement.

 

[snerd]

Oh, and I carefully removed the foam and put it back in place after putting the copper down, and only used 1 layer of the copper tape. A massive improvement.

I believe the correct way is to lay the shield "over" the foam. I thought I read where under it was not as effective.

 

[ur20v]

I believe the correct way is to lay the shield "over" the foam. I thought I read where under it was not as effective.

You cannot use "I believe" and "correct" together in the same sentence while we're experimenting.

I chose not to cover the foam for logical and aesthetic reasons, though I did also cover the lower 'lip' of my battery cover. The way I have done it has made a dramatic improvement in UHF reception in my radio.

 

[snerd]

For sure, whatever works for you!

 

[devicelab]

...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.

I'm using PowerEx batteries as well (the silver/black with yellow logo - 2700mah) and I'm also not seeing a difference.

Using a single layer of copper tape on the battery door.

I notice a very minor difference in the RSSI bars when using just a USB power supply with no batteries on VHF NOAA but that was about it.

I tried the battery door on/off test while searching 450-470 and had no noticeable changes.

I have a later model serial... last four is 7808... and my rubber duck is a Watson 801 antenna.

Perhaps Uniden fixed something?

 

[Comp-100]

You cannot use "I believe" and "correct" together in the same sentence while we're experimenting.

I chose not to cover the foam for logical and aesthetic reasons, though I did also cover the lower 'lip' of my battery cover. The way I have done it has made a dramatic improvement in UHF reception in my radio.

Great job!

 

[troymail]

I have a later model serial... last four is 7808...


Perhaps Uniden fixed something?

Excellent question....... Paul?

 

[bearcat]

Excellent question....... Paul?

I thought this would come up so i bought a new one to test before i made the initial-post on this topic. It did the same thing. Xxx8408. Meaning it had the noise issue

 

[ur20v]

It's a conspiracy, folks. We're all just Uniden's guinea pigs, paying them to improve their product on our own time. Good thing I didn't pay full retail!

(I'm kidding, of course. Well, except for the retail part. Never pay retail if you can help it. Spay and neuter your pets, folks.)

 

[troymail]

I thought this would come up so i bought a new one to test before i made the initial-post on this topic. It did the same thing. Xxx8408. Meaning it had the noise issue

Ok - so possibly no change in the manufacturing, etc. .... but this is another piece of the puzzle that might tell us more...

Environmental? Location? Specific systems folks are listening to?

In my case, I'm listening to some smaller systems with weaker transmissions but there are others that are regional systems with much larger coverage areas. Without the foil, I was hearing pretty much zero of the DMR activity (at least on UHF and with the stock antenna). Now, I'm hearing some activity at distances I would not even expect for some smaller systems.

 

[ecarvalho]

You cannot use "I believe" and "correct" together in the same sentence while we're experimenting.



I chose not to cover the foam for logical and aesthetic reasons, though I did also cover the lower 'lip' of my battery cover. The way I have done it has made a dramatic improvement in UHF reception in my radio.

Hello there! Is that copper spray paint?


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[SCPD]

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???

108-136MHZ airband.

 

[ur20v]

Hello there! Is that copper spray paint?

No sir, 2" wide copper foil "Tapes Master" brand EMI tape ordered from Amazon. A 10' roll cost me a whole $8.

 

[ecarvalho]

No sir, 2" wide copper foil "Tapes Master" brand EMI tape ordered from Amazon. A 10' roll cost me a whole $8.



I know Aldie is a good hour drive from me up near Harpers Ferry, but if you find yourself in my neck of the woods sometime I'd be happy to give you a section for your scanner.

Oh thanks for the offer!!!
It looks so perfect in your picture that I thought you used spray copper such as what is used on motor gaskets. Exceptional job!
I'm heading to Amazon. This is for my SDRplay. I don't own a 436 but a 536 with a desktop discone (UK made (?)) and an inline amp M75. The combination for base scanning works well. I drove with my 536 yesterday tho, that was fun.
Thanks for responding so quickly.

73s PY2BTK


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[IAmSixNine]

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

The SN on mine is 376Z58001xxx and yours appears to be xxx48000xxx
I want to say i also read someone else post theirs with an xxxz38 number.
Does this mean that perhaps the number after the z, being a 3, 4 or in my case a 5 means it was manufactured at different times? different revisions maybe? I ask this because i am NOT having the issues other people are describing and trying 1 and 2 layers of copper tape on my battery door did nothing to help me.
Can those who are in this thread with or with out problems please post the serial number with the last 3 or 4 digits hidden with xxxx Please do include the first 8 or 9 digits and if you are having or not having the issue.

So my SN 376Z58001xxx is NOT experiencing the noise issue and the battery door with copper tape did not help my unit.