BCD436HP/BCD536HP: UHF Reception Issues due to Noise from Battery Compartment
- Thread starter bearcat
- Start date
- Status
k3fs
Member
The window clip mount for the ducky is nothing more than some cable with a BNC mount on it. I used the same duck mounted directly on the radio, and then attached to the window clip mount. Reception improved when the antenna was moved away from the radio by 1-2 feet. It made no difference in what direction. This was true for all antennas I tried, and all of them were tested directly on the radio using the adapter.
I did not realize the extent of the problem, until I had sent the 436 in for repair. Using only the 396XT made me realize how much I was missing. With the door treated, I am able to use my cheapy small duck antenna and get better reception than I did with the untreated door and the Diamond. When I put the Diamond on with the treated door reception is significantly improved.
I don't expect we will hear anything from Uniden. They have been silent on the failure to release advertised features as well.
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 did not realize the extent of the problem, until I had sent the 436 in for repair. Using only the 396XT made me realize how much I was missing. With the door treated, I am able to use my cheapy small duck antenna and get better reception than I did with the untreated door and the Diamond. When I put the Diamond on with the treated door reception is significantly improved.
I don't expect we will hear anything from Uniden. They have been silent on the failure to release advertised features as well.
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.
With a standard door installed. Yes. If I remove the batteries and run your test with USB power I see no change in the noise floor.
The best explanation of this problem would be:
The scanners measured sensitivity at UHF is .2mv (actual measurement). So if the scanner is generating UHF noise constantly amounting to .4mv (made up number for example) Then the scanner will never hear signals unless they are at least .41mv. This is just a made up scenario, but it makes the point. Eliminate the noise (most of it) with the door and the scanner will perform much better.
That is exactly how I found out how bad it was also. When I used my 396xt while the 436 was in the repair campaign.
I measured significant improvement moving the antenna 1-2 inches away from the scanner. Simply converting the stock duck antenna to BNC with an adapter so I had the same connector on base, mobile, and portable antennas made almost all the noise disappear.
Last edited:
Fidgety9996
Member
I did contact them. They copy pasted me the information about how to send the scanner in for repairs (they made no comments).
The problem is im in europe and they accept packages ONLY from US and they send back ONLY to us address. Even better - even if it's their fault you have to cover the cost of the package which from EU would be very expensive.
I'm done with Uniden, this way of disrespecting customers deserves seperate topic.
I asked them on telephone can they at least admit the prbolem is there, they ignored my repeating "we are sorry for invovenience but we can do nothing". CMON!
I have my friends 3600XLT for comparison and i will try to see if the problem is there also. As for now it seems 3600XLT does NOT have this problem and touching batteries gives opposite efect - makes things worse. That would suggest they fixed it in 3600XLT. In what way? we would probably need to see the internals of the device to compare.
So now that you have your findings can you find a freq that cannot be heard without the adapter, then attach the adapter and the unit will receive that same freq. On my known freqs that the 436 cannot hear I still cannot hear them by just adding an adapter. I need the shielded door.
You're missing a few things.
1. The noise level is not constant in every location. Like all RF signals, it decreases in intensity as distance increases from the source. Shielding the source will decrease the signal level picked up by an antenna, but increasing the distance between antenna and source will also decrease the signal level.
2. Similarly, using a longer antenna whose body is (on average) more distant from the noise source will reduce the signal level of the noise. That is why my test saw no difference in received noise when using the Diamond RH77CA--the base of the antenna is farther from the scanner (which increases the minimum distnce between the antenna and the noise), and the antenna is much longer than the stock duck (which increases the average distance between antenna and noise). The combination of those factors reduced the received noise level to negligible levels, even with the battery cover completely removed.
3. The intensity of the noise level in the battery compartment isn't really relevant. What's relevant is the noise level where the antenna is located while the scanner is operating. Given the data so far, it's not clear that the self-interference is a significant issue unless all of the following are true:
a. You're using an SMA antenna connected directly to the scanner.
b. You're using a short antenna, such as the stock rubber duck.
c. The battery cover is not shielded, or it is not installed.
4. I tested whether running the scanner on battery power made a difference in noise level, and it does NOT. Noise level increases by about 3dB (at least in the test configuration shown below) if you have a USB cable plugged in to the scanner, regardless of whether the cable is powered or not.
Your problem is that you are in Europe, and need to deal with Uniden EU rather than Uniden US. If I bought the EU version of the 436, I would have the same problems with exorbitant shipping and warranty service mailing the scanner to Europe.
Last edited:
Fidgety9996
Member
Yes you are right. So all the guys in US send your inquiry to Uniden and send the scanner for warranty repair! (1 year from the date you bought it). Can someone do it and see if they actually fix the scanner?
I see that they have only 1 office in Belgium but i will give it a try.
I had european version for comparison and it turns out the touch test gave opposite results (touching battery worsened the reception). So it looks BCD3600xlt is fixed.
Assuming the 3600 is fixed it would be great to get some pictures of the circuit boards to compare to the 436 to see if there are any differences or added components.
Fidgety9996
Member
Hey guys in my case adding the foil between the foam and batteries didnt help much.
Adding the cooper foil UNDER the batteries made the scanner reception MUCH better but i think it still did not resolved this fully.
My foil is self sticky so its on white non-conductable paper. So it goes like this, plastic>non-conductive part of foil>copper foil > batteries. check this out and see if that works for you.
what is interesting now when you touch batteries you have the opposite effect - reception worsens. exactly the same as in unaffected 3600xlt.
Adding the cooper foil UNDER the batteries made the scanner reception MUCH better but i think it still did not resolved this fully.
My foil is self sticky so its on white non-conductable paper. So it goes like this, plastic>non-conductive part of foil>copper foil > batteries. check this out and see if that works for you.
what is interesting now when you touch batteries you have the opposite effect - reception worsens. exactly the same as in unaffected 3600xlt.
static reception
I tried the cooper tape soluton yesterday.....what a world of difference.... static reduced by at least 50 to 75%
I went a little wild with tape 4 layers inside of battery cover and 1 later on the outside . However P25 still not being picked up ......in some areas no problem just not in my house
I tried the cooper tape soluton yesterday.....what a world of difference.... static reduced by at least 50 to 75%
I went a little wild with tape 4 layers inside of battery cover and 1 later on the outside . However P25 still not being picked up ......in some areas no problem just not in my house
static reception
I tried the cooper tape solution yesterday.....what a world of difference.... static reduced by at least 50 to 75%
I went a little wild with tape 4 layers inside of battery cover and 1 layer on the outside . However P25 still not being picked up ......in some areas no problem just not in my house
I tried the cooper tape solution yesterday.....what a world of difference.... static reduced by at least 50 to 75%
I went a little wild with tape 4 layers inside of battery cover and 1 layer on the outside . However P25 still not being picked up ......in some areas no problem just not in my house
troymail
Silent Key
Similar to my results except that in my case, I could not receive/decode most DMR initially until I put the copper tape on -- then it starting receiving (better).
Might be a completely different issue - LSM/simulcast?
Most of the prior tests showed the opposite of your findings. Meaning tape under batteries made things worse, but if it worked for you then that is great. Can you get any pictures of the 3600 circuit boards?
It may contain the missing link.
A cool test is to search 450 - 470 and as the radio stops on active stuff. Slide the door off and on listen to the change in signal strength (noise). You will probably find that some signals totally disappear with the door off. As mentioned DMR improvement can be drastic.
I should also mention that we found 6 layers of copper tape to be best and when we went further, I think it was eight layers things actually started to get worse.
Last edited:
Fidgety9996
Member
Unfortunately the 3600's owner didnt agree for that :<
the difference in what i tries is that the conductive side was only touching batteries, it wasnt touching the sdcard/board window.
Thanks for asking. Do you have any idea how old the 3600 is? The serial number would tell us. If it is not late 2016. Then I would not expect it to have any updates anyway.
Thanks again and I am happy the shielding made yours better.
I wonder if the foam is pushing the tape against the batteries and therefore, "grounding" it?
Sent from my iPhone using Tapatalk
- Status
Similar threads
