SDS200 Cloned SDS200's behave differently

kirkco

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I have 2 SDS200's that are set-up exactly the same (firmware, profiles, favorites...). They use the same antenna (goes through an active splitter).

They seems to receive everything the same - except for one single active site which is deaf on just one of the scanners.

I even swapped antenna cables (coming from the splitter) and desk positions (they are eight inches apart) - same issue. One scanner is def on a particular site - everything else seems to be equal.

Any ideas? Hardware differences...They are about 1 year apart in age.
 

tvengr

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On the scanner that is not receiving the site, set to Ignore Site NAC. Also, double check that the site frequencies are the same in both scanners and that none are avoided. Also check that the site is not avoided or turned off using a department/site quick key.
 

kirkco

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Thank you for your response. I double checked your setting suggestions and both scanners match. In-fact, I copied the "good" scanner to Sentinel, then reset the "bad" scanner and copied the "good" scanner data to the second. I also tired just swapping SD cards... Same issue persists. I think I may have found a second site that has the same issue (works on one scanner, but not the other). Both sites are Moto P25 in different systems. It seems like a hardware sensitivity/tolerance issue to me. PS, I have also tried different filters settings just for fun..no difference. BTW, the "bad" scanner is the newer one (about 3 months old). Probably would have just assumed bad reception if I didn't have the second scanner working just fine. Next step for me is to disconnect it from my network and take it for a ride.
 

JoeBearcat

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Any frequency relationship between the two sites? Are they both lower on the better scanner?
 

n1chu

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Used to be something called “birdies”, frequencies that would cause scanning to stop. The scanner was generating an internal signal. It was unintended and they called them birdies. The scanner’s IF could be shifted if any of these birdies interfered with normal operations. I’m wondering if differences in components and like component tolerances could be the reason for what you see? It’s a blind stab at it by me... a guess.
 

tvengr

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Are both scanners on at the same time? It is possible that one could be radiating a signal that interferes with the other. Try turning off the scanner that works OK. Oscillator signals can be emitted from one and into the other through the antenna coupler. Also, if the scanners are next to each other, try separating them.
 
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MStep

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(Snipped for brevity.....)

It seems like a hardware sensitivity/tolerance issue to me. PS, I have also tried different filters settings just for fun..no difference. BTW, the "bad" scanner is the newer one (about 3 months old).
I would tend to agree. To quote one of the world's most famous fictional characters:

"Once you eliminate the impossible, whatever remains, no matter how improbable, must be the truth.” - Sherlock Holmes
 

kirkco

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Well....I unhooked everything...took it to another room...with stock antenna... and...it starting talking, even with a lower RSSI! I took it back to its regular place, next to its sister with the normal roof antenna setup etc....and bam...both are still talking! I'll leave them on awhile and see if the positive trend continues. I suspect - like some have speculated - there might be some sort of interference thing going on (themselves, each other, my equipment...). I'll report back if I figure out anything. Thank you for all the suggestions/ideas and quotes!!
 

n1chu

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Even when we think all is the same, there are forces unknown by us that can cause differences. To be truly equal in any comparison we first need to start with a Faraday Cage. Faraday Cages are shielded rooms. Meaning a room shielded from all RF, splurious and otherwise. And even then, there are measurable issues with the first unit interfering with the second unit, and vice versa, in any comparison test.

I do realize I am splitting hairs here. The unscientific comparison testing we all do outside of Faraday Cages is usually sufficient for what we need to see.
 
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