I typoed, I ordered .01uF. They arrived today, I installed one (a major PITA, those things are TINY), and the noise around the battery door is gone. I have 99 left.
BCD436HP/BCD536HP: UHF Reception Issues due to Noise from Battery Compartment
- Thread starter bearcat
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I typoed, I ordered .01uF. They arrived today, I installed one (a major PITA, those things are TINY), and the noise around the battery door is gone. I have 99 left.
Hey I'm glad we found a solution to this but still having to open up a 500 dollar scanner and perform a surgery on it to get it to work correctly just seems wrong. Uniden should have been on top of this. Any chance I could grab a couple of those off of you PM me with price and shipping cost if you can part with a couple.
Thanks,
Bob
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k3fs
Member
The truth is Uniden has started to place the Capacitor on the board. Unfortunately it is difficult to pin point when they did this. The board was modified around the time of the original repair campaign to include the capacitor. Uniden chose to omit that part originally. At some point last year Uniden started to include the capacitor. Uniden has been completely silent on this issue. Won't admit its an issue, and won't deny it. This only demonstrates their lack of willingness to fix the issue. Much as they have been silent on the failure to release the advanced analysis features ("a $100 value right there").
I am not sure what to make of Mattimac's issue of worse reception after the repair campaign. Recently a local unit was sent back and the capacitor was in place on the replacement board. Issue was resolved. I suspect that there may be a problem with the board they swapped out, or another issue. Can you look to see if your board has the capacitor? Certainly sending something in and having it perform worse is not the norm. I would send back to Uniden. They should have some warranty on their repair.
These buggers are small and not easy to work with. Unless you are very comfortable with working on this type of thing I would order a couple of extras. They are very hard to find if you should drop one on the floor. I know a little something about that. I too have a few extras. I ordered from Mouser and they were something on the order of 5 cents a piece. Sending it would be the expense.
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It would be nice to see before and after capacitor results on a spectrum analyzer with sniffer antenna. If anyone is in the LA, CA area and wants to see the results, I have an analyzer and calibrated test antennas handy.
prcguy
prcguy
I don't have a spectrum analyzer, just an SDR dongle on a USB extension cord wearing the factory antenna from the 436. Before installing the capacitor, placing the antenna on the battery compartment would raise the noise floor 10-20dB, depending on the frequency. Now I can't detect any consistent change in noise level. The noise level fluctuates a few dB, but not correlated to placing the antenna next to the battery compartment or any other part of the scanner.
I agree. Installing the capacitor has not made reception worse on my unit, so something else happened.
+1 on this. They also have an annoying habit of sticking to the tip of the soldering iron instead of the circuit board unless held in place. The ones I ordered came packaged in reel tape, rather than loose. They can be sent in a first class letter, if you're willing to forego a tracking number.
I've got 95 available, asking $2 + the price of a stamp for 5, or make an offer if you want more. PM me if interested.
Fidgety9996
Member
I also have sdr so i will try to complete same test. Uniden claims they added the capacitor, i do not want to open the device, i do not want my warranty lost.
Can someone please summarize the last 45 pages with a quick answer on if its worth putting the foil tape in the battery door, and can you give any comparisons of how much better you can lock onto weak signals by doing this mod? (i assume it works if there is 45 pages on the subject)
troymail
Silent Key
I can tell you it made a huge difference for me (and as I recall - many others as well). However, as with anything, there were also those who said it made no difference for them. There are far too many variables.
dcisive
Member
All I can say is it was a world of difference for me. I managed to take some "commercial" quality (thicker) Reynolds Aluminum and folded a piece I cut to the right width over several times. This rendered an equivalent 8 layers of it. I took two small pieces of tape and placed it on the back side where it would interface with the battery door just to keep it in place. I made sure to perfectly trim the now block of foil to conform to the battery door. It was a REAL snug fit at first, but now with some time it has conformed to the shape and is like a part of the door. Without the foil I got decent reception unless in the 100-400mhz range I noted some static on weak channels.
WITH the foil I began picking up a ton of channels (largely tone oriented) that weren't even there before. While some hams were talking on the 147mhz and 447mhz ranges without the foil they got fairly weak, WITH it they were virtually noise free like in the room with me. To me that is a HUGE difference. I've just left the foil in place and forgotten about it. No more noise issues and I have compared it's sensitivity with my 536 and now they are quite identical. So I've let this issue go. The aluminum foils doesn't draw any attention to itself as now it has molded itself to the door and it's like a part of it with no wear issues when I take batteries out to replace with charged ones. No way I'm bothering to send this in as I don't feel the need. So far the display is behaving itself. I sure hope it doesn't fade. I got mine in January from Scannermaster who is kind of known to keep relatively fresh stock on hand. I hope the display never becomes an issue, if not, I won't be sending it in for anything.
WITH the foil I began picking up a ton of channels (largely tone oriented) that weren't even there before. While some hams were talking on the 147mhz and 447mhz ranges without the foil they got fairly weak, WITH it they were virtually noise free like in the room with me. To me that is a HUGE difference. I've just left the foil in place and forgotten about it. No more noise issues and I have compared it's sensitivity with my 536 and now they are quite identical. So I've let this issue go. The aluminum foils doesn't draw any attention to itself as now it has molded itself to the door and it's like a part of it with no wear issues when I take batteries out to replace with charged ones. No way I'm bothering to send this in as I don't feel the need. So far the display is behaving itself. I sure hope it doesn't fade. I got mine in January from Scannermaster who is kind of known to keep relatively fresh stock on hand. I hope the display never becomes an issue, if not, I won't be sending it in for anything.
k3fs
Member
The noise generated by the radio interferes with VHF high to 500mhz. The results all vary to some degree in how much tape to use, and how much improvement you see. Likely since we are all using different materials with different properties. Foil, copper, or EMI spray will all work to decrease the noise, and increase what you hear. EMI spray typically having the best overall results. Foil and copper are a close second. In some instances we saw the noise decreased in certain sections on UHF band with no decrease in the UHF T band or VHF.
The true fix for this is the capacitor Uniden has finally started putting on the board. Due to Uniden's silence on this matter, it is apparent they have no intention of admitting to the problem and fixing it. Even though Uniden has implemented the fix silently. They will not tell you if your radio has the capacitor in it or not. The capacitor improves VHF and UHF reception.
Some good videos demonstrating the problem :
https://youtu.be/hJWp3FsnwPg
https://youtu.be/qv4TlWZXAS8
https://youtu.be/-5OiNho416U
There may be others, and I do apologize for the omission. I just did a quick search.
After battery door modification, you will likely have reception on frequencies you did not before. It's not going to fix the stuff you are receiving, unless it is very weak.
When there is a problem, admit it as soon as possible.
Customers are not stupid. Ignoring or denying a legitimate problem is not the way to handle it.
The true fix for this is the capacitor Uniden has finally started putting on the board. Due to Uniden's silence on this matter, it is apparent they have no intention of admitting to the problem and fixing it. Even though Uniden has implemented the fix silently. They will not tell you if your radio has the capacitor in it or not. The capacitor improves VHF and UHF reception.
Some good videos demonstrating the problem :
https://youtu.be/hJWp3FsnwPg
https://youtu.be/qv4TlWZXAS8
https://youtu.be/-5OiNho416U
There may be others, and I do apologize for the omission. I just did a quick search.
After battery door modification, you will likely have reception on frequencies you did not before. It's not going to fix the stuff you are receiving, unless it is very weak.
When there is a problem, admit it as soon as possible.
Customers are not stupid. Ignoring or denying a legitimate problem is not the way to handle it.
Yeah I'm still trying to decide of my soldering skills are up to it. It's been a long time since I have tinkered with my toys but I will probably grab the capacitors and give it a shot. Just need a little practice first to get back into soldering tiny capacitors to a board with out harming it. :\
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dcisive
Member
Well, I respect the opinions expressed by several folks that have opted for the addition of the resistor and such. However having run extensive test comparisons between my 536 against my 436 both before and after the aluminum foil block I added to my battery compartment, all i can say is it is, WITH the block in place virtually identical in it's reception of weak (and average) frequencies I scannned and monitored with both radios. If there was ANY difference between them I'd be the first to say the resistor is the ONLY answer to this. I can't say if I'm just plain lucky or what the layout is of the boards in this particular 436 I got new from ScannerMaster in January is. Only to say that when applying the battery cover WITH the block of aluminum foil I constructed, it immediately starts to receive channels (like ironically perfectly with NO noise or static in the background) that without it often literally disappear or get very weak indeed. I seriously do NOT think I have a less then stellar performing 536 which I'm using as my main comparison source. My reception in my area in general is quite excellent to begin with. But frequencies in the 100mhz to 500mhz range can indeed be weaker at times depending on what they are. In particular ham's. But once again WITH the aluminum in place in my area it's all I could possibly ask for, so I'm not bothering with the resistor installation option. So far any channel I can get on the 536 I easily get in an equal measure of quality reception on the 436. I'm done.
Well said dcisive I'm just curious how much better the capacitor is than the copper tape I am using. If I can get a better signal I'm all for it.
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That's a whole lot more shielding than the copper on the door. So basically with the capacitor it works correctly. I'll pm you monday when I have some time. Thanks jonwienke
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k3fs
Member
The copper or aluminum tape will improve things for a good section of the UHF band. It will not help VHF, or in most cases UHF T band. There is a lot of variance in results, but the tape will help.
The capacitor is the true fix, and has shown to improve reception of VHF to UHF T. This explains why Uniden has silently started to add this to the radios. I don't think it's too surprising that a capacitor is used to filter the noise.
It's a shame that Uniden is willing to let people risk damaging their radios. Truly this fix should have been in place with the start of the repair campaign, but was not despite the addition of the spots for the components on the new boards.
The least invasive, and safest fix is to use some shielding on the battery door. I chose to do the capacitor install to confirm what we were finding. I would not recommend anyone try it, who is not comfortable in that type of work.
When there is a problem, admit it as soon as possible.
Customers are not stupid. Ignoring or denying a legitimate problem is not the way to handle it.
The capacitor is the true fix, and has shown to improve reception of VHF to UHF T. This explains why Uniden has silently started to add this to the radios. I don't think it's too surprising that a capacitor is used to filter the noise.
It's a shame that Uniden is willing to let people risk damaging their radios. Truly this fix should have been in place with the start of the repair campaign, but was not despite the addition of the spots for the components on the new boards.
The least invasive, and safest fix is to use some shielding on the battery door. I chose to do the capacitor install to confirm what we were finding. I would not recommend anyone try it, who is not comfortable in that type of work.
When there is a problem, admit it as soon as possible.
Customers are not stupid. Ignoring or denying a legitimate problem is not the way to handle it.
I forget, do all BCD436HPs have mounting pads for the noise suppression capacitor or was this only added to the circuit board in later production revisions?
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