The Defpom Forum, for RadioMods, S&M Software and Music by The Defpom

I have been reading about Generators and Oscilloscopes. But, I am not having much luck finding what type of probes to use. I know that for recieve alignment you input RF into antenna and connect Oscope to speaker with 8ohm load. But, not sure how to hook up to show modulation. I assume of corse I will need a 50ohm load. But, what type of probes. Or, can I make a probe for this function. I am all wet behind the ears so please excuse my mistakes. All I need is a little help along the way. I'm open for any sugestions. Maybe you have a diagram or link that would help. Also do I have the right scope to do the job? What I have is a Tekronix 2225 50mhz Dual trace. Has vertical and horizontal. AM/FM Signal generator frequency 100khz-110mhz has internal modulation sorce. I may need a nother device maybe a Audio voltage meter?but, not sure. Any help would be great. I just won't to do It right Please Help. Thanks

I always simply use a X10 probe connected to the antenna jack for rf output measurements. Just make sure your probe is good to at least 40 mhz and you should be ok.

Thanks timrim, I have the probe. So, do you connect it direct to PL259? Do I need a dummy load for RF output measurements or just the probe & Oscope? Thanks!!

Yes, your radio will need to be on a 50 ohm dummy load, just clip the probe on the wire that goes from the circuit board to the SO239 jack. Remember to start on a high volts/div setting on the scope and work your way downward. A lot of the radios will read over 100 volts peak to peak or higher on the scope.

Thanks timrim, I understand now. You helped me out and pointed me in the right direction. Any other suggestions would be greatly apprecianted. Thanks for all the help!

you need to get a 50 ohm 15 to 20 watt 20db attenuator.

the thing is this kind of stuff is getting hard to find. all I can find are attenuator cables that range form 0 to 80 Ghz. they sell for $200.00 to $300.00.

a few years back you could buy a CB 50 ohm 20 db attenuator $25.00.

just do a web search.i,e,

http://www.electronics-radio.com/articl ... -video.php