Connecting 6700 to oscilloscope

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  • Updated 4 years ago
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(this is probably off-topic) I'm thinking of getting a entry-level oscilloscope to learn/experiment with. I know *nothing* about oscilloscopes. Reviews keep sending me to the Rigol DS1054Z and it does look pretty neat.

Anyway, I've been trying to figure out how to connect it to my 6700 to see transmitted signals and stuff (where stuff == i dont know what I'm talking about). I've seen some examples online where people connected their oscope to an unused antenna port on their amp to get the coupling signal without blowing up their oscope.  And I saw on ham nation where Bob built a thingy to output the signal to a rca/bnc port or something like that.  

So, I'm curious what the experts on here have to say?  What is the best way to learn and experiment with oscopes and ham radio and connect them together without blowing up anything? :-)

edit: spelling
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Robbie - KI4TTZ

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Posted 4 years ago

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Dan -- KC4GO

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Alex - DH2ID, Elmer

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I wouldn't recommend to use an oscilloscope for output signal monitoring purposes.
What do you hope to see on the screen? You will see the trace of the hf signal, not
more. You can't even monitor a SSB or AM signal without using a special demodulation
probe.
To monitor my signals I use either my spectrum analyzer, which has special programs
for the measurement of hf modulation signals, or I hook up my IC-756PRO as my
signal monitor with attenuation at -18dB of course :-). As all my TRX have their output
routed through the same AlphaDelta switch, this works fine.
73, Alex DH2ID
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Jon - KF2E

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Robbie,

Have a look at this Youtube video...

https://www.youtube.com/watch?v=y4Zt_LJX1Tc

Jon...kf2e
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Alex - DH2ID, Elmer

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Jon, thank you for the video, quite interesting! Will try this.
But anyway IMO a spectrum analyzer is the much more
valuable instrument for the ham operator.
MyRigol DSA-815 TG was quite affordable and opened
a whole new world of measurements for me :-)
73, Alex DH2ID
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Jon - KF2E

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Alex,

I agree a spectrum analyzer would be better for the task. That said someone wanting to learn more about electronics should probably start with an oscilloscope. I bought this one...

http://www.amazon.com/Siglent-SDS1102CML-Digital-Storage-Oscilloscope/dp/B00GQNNL1U/ref=sr_1_4?ie=UT...

Whatever Robbie gets he should get as high of MHZ as his budget allows.

73,

Jon...kf2e
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Walt - KZ1F

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I have a Heathkit 5MHz dual channel, as I recall, sitting in a closet I could part with.
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Richard McClelland, AA5S

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Tektronix donated one of these to the ARRL, it has a spectrum analyzer and an oscilloscope.  http://www.farnell.com/datasheets/1761667.pdf  Every ham should have one :-)
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Dave - WB5NHL

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Here's the Ham Nation episode on monitoring your signal with a scope.
https://www.youtube.com/watch?v=IB20vnf9zYw

Dave WB5NHL
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Jim W3IPO

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Robbie,
Thank you for asking this question.  I would like to see more "learning" questions like this.  For me and I suspect others this adds more enjoyment to this wonderful radio.

73,
Jim
W3IPO
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Robbie - KI4TTZ

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Thanks for the input everyone! I'll also have to do some research on spectrum analyzers to see what they can do.
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Reg

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Robbie:
Two easy methods to snatch a sample output signal are:  (1)  The Wave Node power/SWR sensors  have an "RF View" option.  This provides a low level signal that can be viewed on an oscilloscope.  Also, the Wave Node software provides some interesting views of the RF signal data.  (2)  CleanRF.com offers a Variable RF Sampler model RF-S5K AND a RF Demodulator Model RF-D.  I have the Wave Node AND CleanRF products and they work fine with my oscilloscope and my spectrum analyzer.
Reg
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Paul Christensen, W9AC, Elmer

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For experimentation, one can simply make an inductive coupling loop by wrapping a half-dozen turns of an alligator test lead around a coaxial transmission line.  A BNC-to-banana adapter works well for this application.  Within limits, the level can be adjusted into the scope or spectrum analyzer (S/A) by adding or subtracting turns.  I normally use commercial Bird and Narda couplers, but in a pinch, I'll just do the above.

I wouldn't dismiss the value of a scope when it comes to making RF measurements.  There are some neat things you can do in the time domain that can't be done in the frequency domain.  A scope is also essential when trying to ensure proper system timing.  For example, I often use a 4-channel scope to monitor the CW key line, RF output after the rig, RF output after the amp, and receive audio coupled to the last channel.  That kind of testing can't be done with a S/A.

There are some exceptionally good values on used test equipment.  With some due diligence, one can find Tektronix and HP gear that won't break the bank. 

Anyone interested in a new digital storage oscilloscope (DSO) should carefully evaluate competing models.  I strongly recommend that any new DSO have variable intensity gradient shading.  This is a trick that some DSO manufacturers use to mimic the effect of a phosphor display.  The Rigol Z series are such DSOs.  If you're making complex measurements (e.g., an AM waveform), you'll want to see variable brightness along the trace.  Common DSOs use one intensity.  My first DSO experience was kinda' disappointing - until I purchased a variable gradient model.  As accurate and maintenance-free as the high end DSOs are, none of them look as good as an analog phosphor display.  That will probably get better over time.

Paul, W9AC



   



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