I agree that you are probably right, but some people might see the word "ground" and take a wire to somewhere it shouldn't be (as darunimal stated).
BCD436HP/BCD536HP: UHF Reception Issues due to Noise from Battery Compartment
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I agree that you are probably right, but some people might see the word "ground" and take a wire to somewhere it shouldn't be (as darunimal stated).
radioman2001
Member
Has anyone tried a few ferrite beads on the lines going to the batteries. If it is indeed coming from the battery compartment, and is being induced from the inside of the radio and out the battery leads that might fix it also.
Quote"
My plan is to take various readings, but I am open to suggestions. Know most don't have access to a SA so here is your chance"
If I was looking for a rouge signal I would start with setting the SA up on the middle of the 450 band set my bandwidth to 20 mhz and just look at the noise floor when you run a probe of a piece of coax with a loop of unshielded area around the problem area namely the battery case. If you pick up any spikes that's when you can zero in on the specific area and frequency.
Quote"
My plan is to take various readings, but I am open to suggestions. Know most don't have access to a SA so here is your chance"
If I was looking for a rouge signal I would start with setting the SA up on the middle of the 450 band set my bandwidth to 20 mhz and just look at the noise floor when you run a probe of a piece of coax with a loop of unshielded area around the problem area namely the battery case. If you pick up any spikes that's when you can zero in on the specific area and frequency.
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devicelab
Whacker Extraordinaire
I wonder if wrapping the batteries up in the copper foil (minus the contacts of course) would be better than messing with the back cover...
Covering the inside of the battery door is way easier, especially since I remove the batteries to charge them.
Agreed, and that's why I was trying to convey the concept of draining off the signal to "somewhere" without specifically saying "ground the batteries." The thought was that the signal must be finding it's way - somehow - back to ground on the outer batteries.
I wonder too about the effect of different battery selection, only from the standpoint that there are minute dimensional differences between some cells. For example, for years I used Powerex's in everything but when the 2300's came out I found that they were slightly longer and fatter and this caused fitment issues in some devices - so I switched to Eneloop. The point being, might the cells in some 436's already be touching each other? (I don't have mine in front of me at the moment to look at the clearance.)
k3fs
Member
Placing foil under the batteries actually made things worse. This certainly is making contact with all batteries. The batteries also have an insulated cover on them, so not sure how much this is connecting the cases together. Still puzzled why results are better with the foam under the shielding.
I made 3 different videos and I'm not able to post them on youtube since the rendering taking about 30 mints to do. I'm trying to do this before I go to work if not I'll post later tonight or tomorrow morning.
I made 1 video of the aluminum foil than 2 video I have 1 layer of copper tape on door 3 video I have 2 layers of copper tape on.
I made 1 video of the aluminum foil than 2 video I have 1 layer of copper tape on door 3 video I have 2 layers of copper tape on.
Door
You have to put the foil tape On the Battery door,I think these batteries somehow make noise perhaps via their contacts to that part of the PC board.
So dont go under the batteries.Do the door only.Theres a picture a few posts back.This is great,everything is nice and clear now!
You have to put the foil tape On the Battery door,I think these batteries somehow make noise perhaps via their contacts to that part of the PC board.
So dont go under the batteries.Do the door only.Theres a picture a few posts back.This is great,everything is nice and clear now!
Great point. And I agree about the vinyl cover on the batteries, but that signal is apparently getting there somehow.
k3fs
Member
I tried it under the batteries early on. Even with the shielding on the battery cover, placing foil under the batteries made things worse.
It does seem as if the stray noise, signal, or whatever, is finding its way to the battery. Findings with placement of the shielding do seem to support this as well.
At home I generally run the 436HP on an outside antenna, but I decided to do the modification anyway. Strange as it may seem, UHF seems to have approved even when on an outside antenna. Totally subjective, so it's likely me.
I then swapped the Radio Shack 800 Mhz antenna onto the radio and receptions seems very clear. Not very much background noise, and both UHF and 800 seem stronger. Again, subjective. I'm going to run the scanner on the RS antenna for a while and get a general impression of performance.
Given the lost cost and ease of the modification, doing it makes sense.
I then swapped the Radio Shack 800 Mhz antenna onto the radio and receptions seems very clear. Not very much background noise, and both UHF and 800 seem stronger. Again, subjective. I'm going to run the scanner on the RS antenna for a while and get a general impression of performance.
Given the lost cost and ease of the modification, doing it makes sense.
After two one-hour commutes, I'm going to cautiously suggest that I'm getting some improvement across the board.
Perhaps it's just fulfillment syndrome, but it does seem like I am getting better reception on formerly weak(er) signals. The hissing interference when plugged into the vehicle mounted USB power supply is not as pronounced as well.
And argue that my external antenna should make this moot all you want, but this is how I use the radio and this is how it seems to be faring better.
Perhaps it's just fulfillment syndrome, but it does seem like I am getting better reception on formerly weak(er) signals. The hissing interference when plugged into the vehicle mounted USB power supply is not as pronounced as well.
And argue that my external antenna should make this moot all you want, but this is how I use the radio and this is how it seems to be faring better.
I could see this happening, especially if the external antenna is relatively close to the radio and/or a gain antenna.
D
darunimal
Guest
Seriously. Nobody said it would improve 700 or 800 maybe high 890's-930mhz
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D
darunimal
Guest
As far as what it is doing:
You are making an electro-magnetic field that is acting as an attenuator, pushing the spurious signal back at itself and keeping it contained.
As per the shunt from the bottom right negative terminal across and up to the second battery there is a little attenuation, but its not very practical if you are going to be taking your batteries in and out for charging. I made a quick and dirty one out of a thin strip of aluminium in an L shape, and bent the right leg down to the negative terminal and with the left leg, made the undulatiuon to go up and over to the 2nd Battery, with grand fears that it could come losse and touch the 2nd batteries positive terminal I would rather not use this approach, (though it does seem to be a good mechincal/pressure holder, I've been known to be ruff with my devices and WOULD NOT advise other to use this solution).
You are making an electro-magnetic field that is acting as an attenuator, pushing the spurious signal back at itself and keeping it contained.
As per the shunt from the bottom right negative terminal across and up to the second battery there is a little attenuation, but its not very practical if you are going to be taking your batteries in and out for charging. I made a quick and dirty one out of a thin strip of aluminium in an L shape, and bent the right leg down to the negative terminal and with the left leg, made the undulatiuon to go up and over to the 2nd Battery, with grand fears that it could come losse and touch the 2nd batteries positive terminal I would rather not use this approach, (though it does seem to be a good mechincal/pressure holder, I've been known to be ruff with my devices and WOULD NOT advise other to use this solution).
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jeffm77
Member
Just for grins and giggles, I tried wrapping the middle battery cell, which i was using a regular alkaline battery, in the copper foil tape just to see what would happen. Found it did nothing. I have 3 layers of the copper tape on my battery door. I have noticed some improvement, might put a 4th layer on in a little bit.
Here is some video I did for today. https://www.youtube.com/watch?v=-5OiNho416U
The noise is much worse in the 406-420 range, so you should see a great improvement on the Tyndall system.
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jeffm77
Member
Nice video Bravo14. I have 3 layers of copper tape on mine and seeing little improvement. I just might add a 4th layer.
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