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Schottky diodes....

C

Cruiseomatic

Dark side of the Sun.
Dec 28, 2011
110
3
28
I've heard for a while these work great to quiet a receiver down without sacrificing sensitivity. If thats the case, Is it the same with almost every "major brand" radio? Such as Uniden, new Cobras, Etc... Most of my stuff is one of those two whether it has the builders name or a re-badge. Would really make the hobby more enjoyable in the area if thats the case though. LOT of RFI around here with all the industrial motors from the refineries, LED lighting at damn near every fuel station, drive thru, taqueria, etc...

Looking for input on this or other ways to lower the s/n I continue to have despite what radio or antenna combo I run.
 

Cruiseomatic said:
LOT of RFI around here with all the industrial motors from the refineries, LED lighting at damn near every fuel station, drive thru, taqueria, etc...

Looking for input on this or other ways to lower the s/n I continue to have despite what radio or antenna combo I run.
Click to expand...

First of all you can make sure you've a good RF ground at the antenna feedpoint and that you are using a RF choke so your coax isn't forming part of the antenna and being a source of the noise itself. One guy who had S9 on his mobile install got it to S0 by doing proper RF grounding and choking.

Secondly you can make sure your own home isn't a source of the interference by switching off the main power and running your radio from a battery. You'd be surprised at just how much noise is made in your own home.

Once you've done that so it is only the antenna picking up the noise generated that you have no control over you can use something like a MFJ1025 or MFJ1026 noise canceller.

Changing diodes won't do a thing to mitigate the noise you have. The above three things will.
 
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I do know, And this might be isolated to just the radio, But my galaxy 959 from '07 and cobra 29 ST from '97, Both I got used, Have some quiet receivers while still picking up distant fixed stations. I'll try the grounding advice though. Thanks. Anyone else try it or is it one of those "swing kit" type things?
 
Cruiseomatic said:
I've heard for a while these work great to quiet a receiver down without sacrificing sensitivity. If thats the case, Is it the same with almost every "major brand" radio?.
Click to expand...
Pretty much. If a manufacturer can save a penny per part but not affect function you can bet your socks they will use the cheaper part.
Schottky Diodes work sort of like this, they rectify just like regular diodes but they don't require .6 volts to conduct. They conduct with a forward voltage drop of .2 volts leaving the difference of .4 volts to be usable signal or AGC voltage.
This might be over simplified but without charts and a lot more explanation it's the best I can do.
If the noise is conducted via the power cable not much use, But it can help with nearby QRM that is not overpowering.
 
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Cruiseomatic said:
I've heard for a while these work great to quiet a receiver down without sacrificing sensitivity. If thats the case, Is it the same with almost every "major brand" radio? Such as Uniden, new Cobras, Etc... Most of my stuff is one of those two whether it has the builders name or a re-badge. Would really make the hobby more enjoyable in the area if thats the case though. LOT of RFI around here with all the industrial motors from the refineries, LED lighting at damn near every fuel station, drive thru, taqueria, etc...

Looking for input on this or other ways to lower the s/n I continue to have despite what radio or antenna combo I run.
Click to expand...
Purchase a west mountain DSP speaker for $185 (best price anywhere) and I'd bet your problems are solved. I myself never bought into those shotkey diodes. There's more information showing they don't work as opposed to one's showing that they do. Your post will most likely show the rift between those who believe and those who don't. I guess it's going to come down to the best argument and or proof they do or don't. Work that is. 73
 
While cutting down audible noise is great, That doesn't quite take care of receiver load. If you have for example, a clean S-6 signal but S-9 noise floor, forget it. Not trying to start a "war" or anything but with so much bad information in this hobby, Its hard to learn whats right from whats wrong. In my area, There is a insane amount of RFI no matter where you are or what antenna you have.
But basically Tallman, They can be helpful aslong as the QRM isn't extreme. Thanks. Trying to figure out what my old cobra and galaxy have that makes them so quiet yet sensitive. Sending a few radios to a tech this week and going to talk to him about them or something to cut the noise floor down some.
 
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Sonar said:
Purchase a west mountain DSP speaker for $185 (best price anywhere) and I'd bet your problems are solved.
Click to expand...
I have a external DSP processor box and it can wipe out the desired signal if not set up.

Cruiseomatic said:
But basically Tallman, They can be helpful aslong as the QRM isn't extreme.
Click to expand...
Yes indeedy! That's what I said.
The radio needs to be properly adjusted as well. I have ham radios that if you don't have the AGC and other items set correctly you won't hear a weak station at all.
 
Alright. Thats good to know. With my new interest back into the hobby and discovery of a new tech, ALL my radios are getting a gone through and cleaned up electronically. Including full alignments and the Schottky diodes if he thinks they'll help with it. I have a good tech locally but hes more "quick fix" type and less thorough than what alot of mine need or what I want. Call me crazy, Stupid, nuts, whatever but, I'm looking at about a grand for all my rigs to be gone through and set up right and put how they're supposed to be. Some even brought back to life. Alot of which I could do but current situation doesn't allow me to have a "station" setup to do much of anything.

Got my Galaxy open now, How can I tell between the Schottky and a normal diode, Or can you just by looks?
 
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