I think it may have been mentioned previously, but Close Call should also benefit from this fix. It's difficult to test this over the air due to external influences though.
BCD436HP/BCD536HP: UHF Reception Issues due to Noise from Battery Compartment
- Thread starter bearcat
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k3fs
Member
There is no difference in reception from when fully charged batteries are placed in the unit to the point the radio shuts down.
I have noted an improvement in close call with the shielded battery door in place. That, is if you consider receiving close call hits from a further distance an improvement.
I am now able to use my cheapo little dual band antenna, and receive things that were not even close to being received before. Actually that antenna is working as I would expect now.
Copper tape should be here within the hour, and things have slowed down here, so hopefully I will get to try some things out.
I have noted an improvement in close call with the shielded battery door in place. That, is if you consider receiving close call hits from a further distance an improvement.
I am now able to use my cheapo little dual band antenna, and receive things that were not even close to being received before. Actually that antenna is working as I would expect now.
Copper tape should be here within the hour, and things have slowed down here, so hopefully I will get to try some things out.
k3fs
Member
HIGHLY unscientific findings, using NO calibrated equipment.
All tests are subjective findings. Testing done on my deck while smoking ribs.
Received copper tape. Tape was EMI tape for electric guitars, and was pretty thin. Essentially copper foil. One layer was not as good as the thicker aluminum tape I had on there.
I had another radio tuned to a local agencies input link that provided a steady carrier with an audio tone, and at times voice traffic. With the battery cover off, the audio from the other radio would be reduced to nothing but static, if the 436 was brought within 4 inches of that radios antenna. I reached the point of diminishing returns at the 6 layer mark. At that point I could place the 436 with shielded battery compartment door to about one inch of the other radios antenna. Increased noise, but not the total obliteration it was without the shielding.
Checked a couple of local frequencies. One DMR channel was lost completely when I took the battery door off, and I would get fully decoded audio with the battery door back on. PGH PD 3 was received with some steam, but when I took the battery door off I mostly lost it. Same held true with PGH Fire 2. Findings are slightly better than the original aluminum tape I used.
I really have noticed minimal change in VHF.
I would say this moves the 436 from poor to average on reception of UHF. The 396XT still receives better than the 436, but really not by much at this point. As a side note, the Pro-96 was the only radio I had that could pick up that input link from my back deck. The 396 and 436 will both pick that frequency up, but not there.
All tests are subjective findings. Testing done on my deck while smoking ribs.
Received copper tape. Tape was EMI tape for electric guitars, and was pretty thin. Essentially copper foil. One layer was not as good as the thicker aluminum tape I had on there.
I had another radio tuned to a local agencies input link that provided a steady carrier with an audio tone, and at times voice traffic. With the battery cover off, the audio from the other radio would be reduced to nothing but static, if the 436 was brought within 4 inches of that radios antenna. I reached the point of diminishing returns at the 6 layer mark. At that point I could place the 436 with shielded battery compartment door to about one inch of the other radios antenna. Increased noise, but not the total obliteration it was without the shielding.
Checked a couple of local frequencies. One DMR channel was lost completely when I took the battery door off, and I would get fully decoded audio with the battery door back on. PGH PD 3 was received with some steam, but when I took the battery door off I mostly lost it. Same held true with PGH Fire 2. Findings are slightly better than the original aluminum tape I used.
I really have noticed minimal change in VHF.
I would say this moves the 436 from poor to average on reception of UHF. The 396XT still receives better than the 436, but really not by much at this point. As a side note, the Pro-96 was the only radio I had that could pick up that input link from my back deck. The 396 and 436 will both pick that frequency up, but not there.
Got my copper tape today. Applied to the battery door over the foam as most noted. Only 1 layer at this point. It's been a few hours of regular DMR scanning with no noticeable difference. It's pretty quiet though, only the usual suspects chatting away. Tomorrow I'll re-read the thread and try some of the suggested testing. My 436HP was purchased in the beginning, early March, 2014.
I wanted to mention, I applied 1 layer of tape to the battery door over the foam on my 396xt. On regular old UHF analog, I have noticed less noise in transmissions, and 1 more bar than normal on a few of the frequencies I normally monitor. This is using the RS 800MHz antenna.
I wanted to mention, I applied 1 layer of tape to the battery door over the foam on my 396xt. On regular old UHF analog, I have noticed less noise in transmissions, and 1 more bar than normal on a few of the frequencies I normally monitor. This is using the RS 800MHz antenna.
Funny you should bring the 396 topic up. I checked the middle battery, positive side of my 396 today and there is the same noise on that radio, but very low level. And based on the fine performance of the 396 I was no even going to bring it up. Let us know how you make out as you apply more layers.
I rarely use my 436 in a mobile environment. Usually it is here at home plugged into an external antenna. Given that it was so cheap to by some of the copper tape referenced earlier in this thread, I bought some. It arrived today. For the first time since I've owned the 436, i decided to test the 436 on whatever DMR signals I could pick up on the rubber ducky in the basement of the house. Of course, this was very few.
Well, I used the custom search to search between 450 and 470, and I made note of all of the DMR signals I had heard. By simply listening, none of them sounded like they had any local noise inducedon them. They simply sounded weak, which they were (1 bar maybe).
Then I cut off two squares of copper tape to completely cover the inside surface of the battery lid, placing the copper tape over the padding. So I have two layers.
I then went through and ran the custom search, and I instantly realized something -- In search mode it is supposed to display DMR trunked system information on the screen when I was picking up a DMR signal. Prior to putting the tape on, I only "heard" the signals -- nothing was displaying on the screen. After I put the tape on and scanned the same band, for every DMR signal that it stopped on the display was showing the relevant trunked system information.
I'll be damned, but the copper tape suggestion absolutely has a positive effect on local noise. Now, the weakest of signals seems to be picked up strong enough to display at least some trunked info. I have no numbers to give anyone. I can simply say that before putting on the tape, every trunked signal I came across when running a 450-470 search using the rubber ducky in the basement resulted in no trunked information displayed on the screen, and after putting the tape on nearly every trunked signal that the scanner stopped on produced trunked system information on the screen.
Thanks bearcat for bringing this up. I think I'm going to start digging through all my scanners and adding some shielding in various sections of the case to see if it makes a difference.
In my case, the tape definitely improved reception on 450-470 mhz significantly. I don't know about any other band.
Mike
Well, I used the custom search to search between 450 and 470, and I made note of all of the DMR signals I had heard. By simply listening, none of them sounded like they had any local noise inducedon them. They simply sounded weak, which they were (1 bar maybe).
Then I cut off two squares of copper tape to completely cover the inside surface of the battery lid, placing the copper tape over the padding. So I have two layers.
I then went through and ran the custom search, and I instantly realized something -- In search mode it is supposed to display DMR trunked system information on the screen when I was picking up a DMR signal. Prior to putting the tape on, I only "heard" the signals -- nothing was displaying on the screen. After I put the tape on and scanned the same band, for every DMR signal that it stopped on the display was showing the relevant trunked system information.
I'll be damned, but the copper tape suggestion absolutely has a positive effect on local noise. Now, the weakest of signals seems to be picked up strong enough to display at least some trunked info. I have no numbers to give anyone. I can simply say that before putting on the tape, every trunked signal I came across when running a 450-470 search using the rubber ducky in the basement resulted in no trunked information displayed on the screen, and after putting the tape on nearly every trunked signal that the scanner stopped on produced trunked system information on the screen.
Thanks bearcat for bringing this up. I think I'm going to start digging through all my scanners and adding some shielding in various sections of the case to see if it makes a difference.
In my case, the tape definitely improved reception on 450-470 mhz significantly. I don't know about any other band.
Mike
More testing today Copper vs Aluminum
I found a few interesting things today. I was lucky enough to have some copper tape gifted to me. I do not have an SA so my testing is done by probing with an AirSpy and Spectrum Spy software. The numbers are not intended to be true measurements. They are just comparisons between each other.
All tape was applied over the foam. I still get lesser results when I go under the foam in all cases.
All freq = MHZ
All DB numbers refer to noise floor increase when probing the middle battery plus side.
460.0000 MHZ center freq 200 MHZ span
No battery door
350 - 425 +30db
425 - 520 +20db
520 and up noise drops off
Copper Battery Door
350 - 480 +5db
480 - 550 +15db
Aluminum Battery Door
350 - 480 +10db
410 - 550 +5db
It is interesting how the peak noise when shielded is in two different areas based on the material used. So based on this if you like MILAIR use copper, if you like the 450 band use aluminum. Well not really this is one test by one person who do not have the proper equipment to make a scientific proclamation.
Also of interest. I lined the entire case with foam and covered that with aluminum. It made things worse maybe worse than an un-shielded battery case. Also I monitored the noise with each layer of copper once at six layers things were good. Layer 7 started to hear more noise, Layer #8 was about the same as the case with foam, horrible. Something must go hay wire when the foil starts getting too close to the battery. So I stopped a 6 layers and frankly I would be splitting hairs to say the copper was better than aluminum. They are about the same. If I had to pick copper would get the edge.
At this point I have two doors one copper and one aluminum. My radio is working better than ever. In fact side by side with my 396 they are about equal now. I am going to leave well enough alone and use what I have.
At some point we should have some data from the young lady who was getting some equipment on loan. I am looking forward to that. I have more spare doors on the way and will probably spray one to see how that works.
Hopefully one of the really smart folks on here or Uniden can find the miracle cure
I found a few interesting things today. I was lucky enough to have some copper tape gifted to me. I do not have an SA so my testing is done by probing with an AirSpy and Spectrum Spy software. The numbers are not intended to be true measurements. They are just comparisons between each other.
All tape was applied over the foam. I still get lesser results when I go under the foam in all cases.
All freq = MHZ
All DB numbers refer to noise floor increase when probing the middle battery plus side.
460.0000 MHZ center freq 200 MHZ span
No battery door
350 - 425 +30db
425 - 520 +20db
520 and up noise drops off
Copper Battery Door
350 - 480 +5db
480 - 550 +15db
Aluminum Battery Door
350 - 480 +10db
410 - 550 +5db
It is interesting how the peak noise when shielded is in two different areas based on the material used. So based on this if you like MILAIR use copper, if you like the 450 band use aluminum. Well not really this is one test by one person who do not have the proper equipment to make a scientific proclamation.
Also of interest. I lined the entire case with foam and covered that with aluminum. It made things worse maybe worse than an un-shielded battery case. Also I monitored the noise with each layer of copper once at six layers things were good. Layer 7 started to hear more noise, Layer #8 was about the same as the case with foam, horrible. Something must go hay wire when the foil starts getting too close to the battery. So I stopped a 6 layers and frankly I would be splitting hairs to say the copper was better than aluminum. They are about the same. If I had to pick copper would get the edge.
At this point I have two doors one copper and one aluminum. My radio is working better than ever. In fact side by side with my 396 they are about equal now. I am going to leave well enough alone and use what I have.
At some point we should have some data from the young lady who was getting some equipment on loan. I am looking forward to that. I have more spare doors on the way and will probably spray one to see how that works.
Hopefully one of the really smart folks on here or Uniden can find the miracle cure
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That there is funny!! The second joke (I think) on this thread and they were both really good! Keep 'em coming"Customers who bought this also bought... bcd436hp."
I guess I forgot to mention. I did try some combinations or copper and aluminum without any significant findings. The person who posted the CAP fix later came back and stated he was not getting the results he thought he was at first. That certainly does not mean others cannot experiment with both of these ideas
I didn't realize how much tape was being applied to other radios so I stopped with 3 layers. I may try to add more tonight and see how much more of a difference it makes. I know it was dramatic with the shielding added so I'm curious if more layers would help.
436HP: I am noticing some favorable results on UHF searches. I would even say VHF is a bit better. I guess tonight I'll add 2 more layers and see if it gets any better. I have been using the 436HP everyday since I bought it back in 2014. Most of my "testing" thus far has been simply listening to what I am able to hear compared to what I was able to hear over the last 2+ years. I can with certainty, say that I am hearing more today than I did yesterday during a scan.
In regards to the 396xt, I am getting much better receive on my county's UHF "T" band system. Much clearer audio, and I'm receiving some of the "problem" channels better.
Disclaimer: I'm going to throw this out there. I don't know that the copper has anything to do with this. It most likely doesn't. I did have some squelch tail on my county's system with the 396xt. Today, the squelch tail is almost non existent.
In regards to the 396xt, I am getting much better receive on my county's UHF "T" band system. Much clearer audio, and I'm receiving some of the "problem" channels better.
Disclaimer: I'm going to throw this out there. I don't know that the copper has anything to do with this. It most likely doesn't. I did have some squelch tail on my county's system with the 396xt. Today, the squelch tail is almost non existent.
Just be careful to not over did it. There is a point were it will get worse. Why? I have no idea. My threshold was 6 layers. I think K3FS was 7. So your mileage may vary.
Thanks!
Thanks, I somehow missed that even though I've been trying to follow closely. Hoping to hear on the SA tests soon with more detailed information on the source and how the radiation pattern for the emission(s) is being affected by the different mods.
johnnyelectron
Member
- Joined
- Dec 19, 2002
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- 201
Where to put tape on a 396XT
Hi, on the 396XT- where did you put the tape? Aluminum ductwork tape works on 450 where? Thanks! 73
Hi, on the 396XT- where did you put the tape? Aluminum ductwork tape works on 450 where? Thanks! 73
copper tape
I have tried the copper tape and have found that it improves my ham side of the radio and the aircraft side
of the radio. it really makes some big difference. it was worth the 7.00 spent for the tape.
I have tried the copper tape and have found that it improves my ham side of the radio and the aircraft side
of the radio. it really makes some big difference. it was worth the 7.00 spent for the tape.
Webheadfred
Member
On further review, after removing the foam and putting copper tape on the battery cover back, I replaced the foam and put tape on it. Just in search mode, it was picking up DMR on the UHF bands which it wasn't doing previously. It didn't pick up anything I programmed for DMR because I must be an idiot. My 536 arrives Thursday. More fun in store.
Oddly enough I had lined the whole door with foil over padding on Sunday night and saw the saw the same thing, it actually made it worse.
I had ordered spare doors at the onset of this and have experimented a lot with different foil/padding combinations and have found (for me at least) a single vertical strip across the padding in the factory location works the best.
Uniden Parts must be wondering why there is such a rush on battery door lid orders. I have more on the way also. I ordered the Nickel RF/EMI spray today. It is not cheap but offers 29db of shielding. Much cheaper than buying another scanner which I was about to do. I will have it Thursday. So based on drying time I may know more on how that works sometime Thurs night or Friday.
Today I took a bike ride to the city and found three fairly distant DMR Control channels that I could decode using the aluminum door, but only heard undecoded DMR data on the copper door. Now this does not mean the the copper is not better in some other freq range, but it is of interest.
Get you spare battery lids before they are gone!
I should have mentioned that I was able to hear many repeater input freqs with either door that I could not hear with the door off.
Today I took a bike ride to the city and found three fairly distant DMR Control channels that I could decode using the aluminum door, but only heard undecoded DMR data on the copper door. Now this does not mean the the copper is not better in some other freq range, but it is of interest.
Get you spare battery lids before they are gone!
I should have mentioned that I was able to hear many repeater input freqs with either door that I could not hear with the door off.
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