This is an idea I had as well. Can't hurt to try! The 436 I'm using right now is on loan so I can't try this mod with it but the SDR is definitely prone to some interference.
BCD436HP/BCD536HP: UHF Reception Issues due to Noise from Battery Compartment
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This is an idea I had as well. Can't hurt to try! The 436 I'm using right now is on loan so I can't try this mod with it but the SDR is definitely prone to some interference.
Yes indeed... the plastic casing offers no shielding to in-home noise. Again thanks for the info on the material you used.
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troymail
Silent Key
Sounds like you weren't experiencing the issue this fix is intended to solve so I wouldn't expect that you'd see a difference. IF you are receiving well already, this isn't likely to help much if at all (I believe). In my case, I can tell you it's extremely night and day.
Having said that - I'm curious what (UHF) DMR systems you are monitoring and how far they are from you. Also, can we assume you're using the stock 436 antenna?
Webheadfred
Member
Really nice job. I should get my tape Monday. How hard was it to pull the foam up?
Is there not a vent on the side of the SDR sticks (I'm thinking the Nooelec blue ones) which shouldn't be covered up? Or is that just for the IR remote control that came with the thing to be able to "see" the IR receiver?
I have my roll of copper tape with me today and two of the SDR sticks on my desk...
I have my roll of copper tape with me today and two of the SDR sticks on my desk...
I suspect we are getting off the 436 subjects here LOL
To quickly answer your question, SDRplay is not a stick and the case has no ventilation.
I'm glad to see reported data on the 436 improved reception with the copper shields that I decided to give it a try on my SDRplay box.
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I realize the SDRplay is not the same as the sticks that I described in my question. That's why I described the sticks in my question. Like you, I have a different device that I want to try shielding to see if things improve, but I'm leery of turning it into a molten pile of nickle and plastic if I let it overheat.
As i mentioned in my previous post i tested it with stock antenna and RS800mhz antenna. However for day to day use i stick with the RS800mhz antenna. http://forums.radioreference.com/un...mprove-your-uhf-reception-12.html#post2617022
The main channel i used for testing was one about 10 miles from me at a local hospital. 454.575 security uses a single channel DMR. http://forums.radioreference.com/un...mprove-your-uhf-reception-13.html#post2617082
There are other DMR systems that are in down town dallas with a much higher power output that i can monitor with no problems that are also about 10 miles out.
I guess it helps that im using Hytera PD782 and PD682 radios to monitor some of the same things while im trying to monitor on my scanner.
Testing with copper tape battery door on and off i had better results with it off. Since my unit doesnt appear to have the issue thats why i was wondering about other peoples SN. Wondering if its been fixed in later dated units or if it was perhaps a defective part supplied to uniden during the manufacturing which may indicate a specific batch.
436 How to Improve Your UHF Reception
Sorry I missed your point before.
If the device(s) you use need vents I would not cover them.
You could try a ferret set on the USB cable between the dongle and the computer (if you aren't plugging it directly into the USB port). Most important to note it is, home noise will still be an issue if the antenna is also inside / indoors.
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Sorry I missed your point before.
If the device(s) you use need vents I would not cover them.
You could try a ferret set on the USB cable between the dongle and the computer (if you aren't plugging it directly into the USB port). Most important to note it is, home noise will still be an issue if the antenna is also inside / indoors.
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I do not do a lot of aviation monitoring. I can tell you that i am getting close call hits on air band from planes flying over my house that i never heard for the two years i had this radio
If you search 450 - 473 with the door sheilded on or off the results are the same. Do not evalute what you are already hearing. Look for what you are not hearing
k3fs
Member
I have noticed an improvement in close call function as well.
I got close call hit on family radio at a road contruction stop/slow sign worker about 200 yards away
436 How to Improve Your UHF Reception
I'm 7 miles away from the tower at IAD and I hear them Ok but the DMR is so low power that I have to be 2-3 miles close to hear any of it.
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I'm 7 miles away from the tower at IAD and I hear them Ok but the DMR is so low power that I have to be 2-3 miles close to hear any of it.
Sent from my iPhone using Tapatalkhttps://vimeo.com/176756028
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Have you tried the shielded battery door? Sorry i just noticed the picture you have a 536. This fix is related to the 436
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The way Close Call works is (the way I understand it) measuring how strong a signal is compared to the noise floor, and if it reaches a certain threshold, it is considered a close call candidate. So improvements to the "quality" of the noise floor should theoretically improve your Close Call experience.
no no... this is a 536. I was showing the OK reception in VHF... and thinking of my lack of it for their DMR dulles 5/6 sites
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I would love to know how much noise is coming through your sprayed door. Obviously pin pionting the noise source. Component? What is the freq and level of noise without a shielded case. You appear to have the expertise to give us some super data Thanks !!
I have been surprised by the success of some when the foil is on top of the foam and in close contact with the batteries which got me to thinking. Very dangerous!
Battery is a cylinder with a closed end representing the negative and open at the positive for the guts to make contact with the positive post.
3 stack battery arrangement, center battery "floats" meaning isolated from radio other than electrical contact with top and bottom battery.
Bottom battery negative (right side) is connected to antenna ground (threads) as measured with ohmmeter.
Top battery positive (left side) is the hot side of the radio.
Other have reported the noise level increase around the middle battery which I have no explanation for.
Capacitor is formed when conductive surfaces are placed in close proximity and separated by a dielectric (battery insulating sleeve) from each other.
Here my theory as why the foil over the foam works/helps as it is placing the foil in contact with the insulating sleeve or the batteries. The noise level at the middle battery is being capacitively coupled to the negative cylinder of the bottom battery, part the of the radio ground system. The equivalent circuit is two decoupling capacitors in series which reduces the capacitance which is already small. What I see would be the most effective fix is decoupling caps at each end of the middle battery to the radio ground plane. Really hard to tell if its a band-aid or a fix as we don't know the source of the noise.
I have not seen the schematic, but I am aware of complex microprocessor working with RF circuit have multiple "grounds" to help control and isolate noise and cross-talk. So my use of the word ground is open ended as which one is the best.
That's my story and I am sticking to it.
Battery is a cylinder with a closed end representing the negative and open at the positive for the guts to make contact with the positive post.
3 stack battery arrangement, center battery "floats" meaning isolated from radio other than electrical contact with top and bottom battery.
Bottom battery negative (right side) is connected to antenna ground (threads) as measured with ohmmeter.
Top battery positive (left side) is the hot side of the radio.
Other have reported the noise level increase around the middle battery which I have no explanation for.
Capacitor is formed when conductive surfaces are placed in close proximity and separated by a dielectric (battery insulating sleeve) from each other.
Here my theory as why the foil over the foam works/helps as it is placing the foil in contact with the insulating sleeve or the batteries. The noise level at the middle battery is being capacitively coupled to the negative cylinder of the bottom battery, part the of the radio ground system. The equivalent circuit is two decoupling capacitors in series which reduces the capacitance which is already small. What I see would be the most effective fix is decoupling caps at each end of the middle battery to the radio ground plane. Really hard to tell if its a band-aid or a fix as we don't know the source of the noise.
I have not seen the schematic, but I am aware of complex microprocessor working with RF circuit have multiple "grounds" to help control and isolate noise and cross-talk. So my use of the word ground is open ended as which one is the best.
That's my story and I am sticking to it.
I agree the shielded case is a band aid. There is a component existing or add on solution. I just do not know what it isI have been surprised by the success of some when the foil is on top of the foam and in close contact with the batteries which got me to thinking. Very dangerous!
Battery is a cylinder with a closed end representing the negative and open at the positive for the guts to make contact with the positive post.
3 stack battery arrangement, center battery "floats" meaning isolated from radio other than electrical contact with top and bottom battery.
Bottom battery negative (right side) is connected to antenna ground (threads) as measured with ohmmeter.
Top battery positive (left side) is the hot side of the radio.
Other have reported the noise level increase around the middle battery which I have no explanation for.
Capacitor is formed when conductive surfaces are placed in close proximity and separated by a dielectric (battery insulating sleeve) from each other.
Here my theory as why the foil over the foam works/helps as it is placing the foil in contact with the insulating sleeve or the batteries. The noise level at the middle battery is being capacitively coupled to the negative cylinder of the bottom battery, part the of the radio ground system. The equivalent circuit is two decoupling capacitors in series which reduces the capacitance which is already small. What I see would be the most effective fix is decoupling caps at each end of the middle battery to the radio ground plane. Really hard to tell if its a band-aid or a fix as we don't know the source of the noise.
I have not seen the schematic, but I am aware of complex microprocessor working with RF circuit have multiple "grounds" to help control and isolate noise and cross-talk. So my use of the word ground is open ended as which one is the best.
That's my story and I am sticking to it.
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