| Author |
Message |
    
Joey_migs
Junior Member
Username: Joey_migs
Post Number: 30
Registered: 9-2009
| | Posted on Sunday, October 04, 2009 - 12:45 pm: | 
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Can a scope be attached to a transmission line via 'T' connector with connection to scope. By comparing the ratio of the voltage at the maxima and minima (peak and troughs)of the waveform I think it is possible. Any thoughts?
Thx,
Joe |
Tech833
Moderator
Username: Tech833
Post Number: 1753
Registered: 8-2002
| | Posted on Sunday, October 04, 2009 - 3:10 pm: |
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No.
A scope used in that manner would be good for showing your modulation envelope though. |
Joey_migs
Junior Member
Username: Joey_migs
Post Number: 32
Registered: 9-2009
| | Posted on Sunday, October 04, 2009 - 6:41 pm: |
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So there is no way to use a dual channel oscilloscope, one channel triggered by the incidental wave, the second channel monitoring the reflected wave triggered also by the incidental wave. Superimpose the waves on one another and note if wave-forms cancel one another (180 degree out-of-phase). I still say it can be done, not by me I assure you - but someone.
Actually, with a RF signal generator and a scope I believe one could simulate functions of an antenna analyzer.
Thanks,
Joe |
Five
Junior Member
Username: Five
Post Number: 30
Registered: 7-2009
| | Posted on Sunday, October 04, 2009 - 8:00 pm: |
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One should use a directional coupler if using scope for viewing radio output of any kind so there is no technical difficulties. :>) That is my opinion and I am sticking to it! |
Bruce
Senior Member
Username: Bruce
Post Number: 5201
Registered: 9-2003
| | Posted on Sunday, October 04, 2009 - 7:52 pm: |
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WHY ?
As for measuring antennas I use a noise bridge It has worked for me for 40 years. |
Tech833
Moderator
Username: Tech833
Post Number: 1755
Registered: 8-2002
| | Posted on Sunday, October 04, 2009 - 10:32 pm: |
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A scope is not a magic tell-all instrument. It is most commonly used for viewing a waveform.
You could use a directional coupler and get a forward sample and a reflected sample, then put both waveforms on the display at the same time. Still not much use.
If you had a spectrum analyzer and a tracking generator and a bridge, you could sweep your antennas. Now, that is pretty useful. Scopes, not as useful in this case. |
Joey_migs
Junior Member
Username: Joey_migs
Post Number: 33
Registered: 9-2009
| | Posted on Monday, October 05, 2009 - 12:57 pm: |
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The sweep generator and bridge are feasible but a spectrum analyzer is way out of my price range. Albeit, My question was mainly academic and more for my edification on the idea than anything else.Although using it to display my modulation carrier envelope sound interesting.
Thanks for all you guy's answers - I appreciate it.
Joe Migs |
Bruce
Senior Member
Username: Bruce
Post Number: 5202
Registered: 9-2003
| | Posted on Tuesday, October 06, 2009 - 6:33 am: |
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I have 3 spectrum analyzers and a sweep generator,several signal generators as well as a noise bridge several scopes ....now how do you measure SWR ......
I measure it once my noise bridge shows me where it is with a $ 20 SWR meter.
Sometimes I get fancy and use either my DRAKE W4 or my BIRD#43 ..... |
Five
Junior Member
Username: Five
Post Number: 31
Registered: 7-2009
| | Posted on Tuesday, October 06, 2009 - 10:06 pm: |
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Your right scopes don't show everything and a good cheap SWR meter is probably the best bet. There are many different ways to accomplish the same task and nowadays the least expensive way can be as good as any other although for academics seeing it while it happens can aid in understanding how things work. |
