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Oscilloscope for cb radio?

543_Dallas said:
I use a 30mhz scope to monitor modulation and do receiver alignments on CB radios. It does everything I need and I can see when a junk amplifier is oscilating. Found it on epay for under $50 shipped. Super glued a broken knob and and it was good enough for me.

I use a bnc connector to mount an RF pickup inside amplifiers, watt meters or whatever I have inline. It makes for one less jumper but you can build a pickup in a small project box.

Some guys wrap a dozen wraps of small gauge wire around their coax for a pick up. It does work but the waveform on the scope didn't look as clean for me.

As for the RX alignment all I use is an 8 ohm ceramic resistor and a bnc connector. For the simple tasks I do I haven't needed to buy any probes.
Click to expand...
How do you take rf samples from your transmitter. If that the pickup box?
 
805 california said:
How do you take rf samples from your transmitter. If that the pickup box?
Click to expand...

The blue teflon wire is my RF pickup. It's connected to a bnc connector mounted in the amplifier case. Originally the wire looped around the output and went to ground but this picked up noise from the blower or something. The way it is now works perfectly.
 

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Robb said:
Did you read thru the pages on that link I posted?
There are schematics to follow; I would do that.
Not hard at all to build . . .
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No kidding. I showed him how to do it with a bnc connector and piece of scrap wire. I don't think it could be done any simpler.
 
805 california said:
What components/values do I need to make a rf sampler box? I'm wanting to use it for cobra 29 ltds/ galaxy 959? Thanks for the help
Click to expand...
This RF sampler will work for any radio.

It will require a 100 om resistor, a ferrite bead, a female BNC connector, and a six inches of enameled solid copper wire. Assemble as per the schematic and photo.

You will also need a 50 ohm dummy load, preferably rated for 100 watts, for termination for the radio's output.
 
Robb said:
This RF sampler will work for any radio.

It will require a 100 om resistor, a ferrite bead, a female BNC connector, and a six inches of enameled solid copper wire. Assemble as per the schematic and photo.

You will also need a 50 ohm dummy load, preferably rated for 100 watts, for termination for the radio's output.
Click to expand...
10-4, thanks for the specifics. What kind of metal is used? Yeah I got a 100 watt dummy load. How much of a sample is generated into a scope with this setup?
 
Metal? If you mean 'ferrite', it is a mixture of ceramic and iron. Ferrite soaks up a little of the electromagnetic field that surrounds any electrically charged wire and does not affect the radio's performance. Then the coated copper wire is wrapped around the ferrite and that free current is sent to the BNC connector thru the resistor; and the other end of that copper wire is grounded. AS far as signal strength goes, it is more than capable enough to sense the small output of a standard CB - both below and beyond.
 
Robb said:
Metal? If you mean 'ferrite', it is a mixture of ceramic and iron. Ferrite soaks up a little of the electromagnetic field that surrounds any electrically charged wire and does not affect the radio's performance. Then the coated copper wire is wrapped around the ferrite and that free current is sent to the BNC connector thru the resistor; and the other end of that copper wire is grounded. AS far as signal strength goes, it is more than capable enough to sense the small output of a standard CB - both below and
Click to expand...
 
Robb said:
Metal? If you mean 'ferrite', it is a mixture of ceramic and iron. Ferrite soaks up a little of the electromagnetic field that surrounds any electrically charged wire and does not affect the radio's performance. Then the coated copper wire is wrapped around the ferrite and that free current is sent to the BNC connector thru the resistor; and the other end of that copper wire is grounded. AS far as signal strength goes, it is more than capable enough to sense the small output of a standard CB - both below and beyond.
Click to expand...
Good deal, thanks for the info. As in the metal, what material is used to bolt the BNC connector and pl connectors to?
 
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