Video: Oscilloscope Balanced Antenna System Tuner Performance Test

Hello Friends:
This video was made for anyone who wanted to see what is really happening at the carrier wave level when RF is leaving your station! I made two short videos, woven together showing you how to use a simple oscilloscope to measure the balance of your antenna tuner and antenna system. I will post additional videos regarding SDR technology, amplifiers, audio processing and more on my new channel.
Hope you enjoy! Tyler, KA0KA

 

I wonder what it would look like with various levels of real TX RF up to the top of the tuner specs?
And also the effect of near objects on the transmission line?

Lab exercises are great to show the concepts and basics but often do not translate to the real world.

Carl

 

Looks darn real world to me!

KA2RRK

 

Yes the antenna system test part of the video was with my 280 foot vertical loop feed with the 600 Ohm line into the shack. This is a zoomed out photo of the shack that was shown the at end of the video, ladder line can be seen in back area!

 

Very informative and well done, 'cept for the au courant use of a background music track (a personal bugaboo of mine). I particularly liked the attention to the phase shift and use of the add mode feature of the scope. Three thumbs up.

 

Im not criticizing the procedure or equipment used and had worked in RF labs most of my working years plus have a nice lab at home that covers from audio to well into the microwaves.

OTOH I'll start off by asking what RF power levels were used?

Im sure you, maybe not others, will understand that the RF fields in the OWL expand with increasing power and what may be minor at low power becomes very important as power increases. That may cause feedline radiation which is not desirable in a balanced system.

On receive even a small imbalance can cause common mode pickup.

I also find the backround "noise" very annoying.

Carl

 

Liked also , but also do not like music in this type of video .
At least for me , I would like to see things not working correctly - then demonstrate finding fault & correcting , rather than showing all working good / kinda telling us the butler did it and no storyline

Thanks John

 

nice job and I enjoyed talking to you on 40 meters this morning

 

Comments:
1) Ditch the music track. You're trying to give a technical presentation and we're not at a dance club.
2) The video seemed more about setting up a dual-trace o'scope than anything else.
3) To Carl's fine point....so the system is almost ballanced at low power levels. That's the easy part. What about real-world practical impacts from say a real dipole?
4) Unless the tuner is link coupled, the output V & I in each leg is a function of the balun type and the load ballance.
5) Finally...ditch the o'scope. Use an RF ammeter in each leg to see if the CURRENTS are equal. That is what really matters if your concern is feedline radiation.

 

Nice work as far as you went, thank you.

But I agree the music is not helpful.