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I have a magnetic loop antenna that takes a long time to tune and of course, while tuning it, I need to be transmitting.

What is the best procedure for tuning on air? I understand I need to check the frequency and identify myself before transmitting, but what if I'm nowhere near resonant when I do this? I'll just be getting louder and louder as I reach resonance, and probably no one heard me calling that I was performing a test initially.

So I guess my first question is, what's the procedure from start to finish for tuning on the air? Keeping in mind, I can't quickly tune with my radio; due to the magloop, tuning is very specific and the SWR is too far out for my radio to automatically fix this. It's a very long process to tune it properly.

Also, is it acceptable to simply put out a carrier signal while tuning? This is definitely more accurate and quick than tuning against a phone transmission, but is it allowed?

I'm located in California in the United States in case this is a locale specific answer.

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    $\begingroup$ I think this is a great question in that it's answer is something that's not usually covered in the rules or the common new operator materials. And it's definitely the kind of thing this site is about. $\endgroup$
    – WPrecht
    Commented Dec 10, 2013 at 21:12
  • $\begingroup$ It's an interesting one. I've been told several best practices by different people over the years. $\endgroup$
    – David VK2VXK
    Commented Dec 10, 2013 at 22:21
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    $\begingroup$ Adjust it close with a noise bridge to minimize adding QRM. $\endgroup$
    – Optionparty
    Commented Dec 20, 2016 at 4:02
  • $\begingroup$ Generally you can do some rough tuning without transmitting by peaking the noise floor on receive, or peaking a relatively constant received signal. Unfortunately I can't really do this with my auto-tuner. $\endgroup$
    – Chinasaur
    Commented Mar 26 at 23:57

3 Answers 3

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I am pretty sure this isn't covered explicitly in Part 97 and probably falls under the "don't cause intentional interference" clause.

The practice I was taught is this:

  1. Tune off the pileup you found several KHz to a 'clear' spot
  2. reduce power to the either the lowest the rig will go or the least that will facilitate the tuning process
  3. Switch to CW mode
  4. key the transmitter (hold down the PTT) and tune away

When you are done:

  1. Unkey the transmitter
  2. Send your callsign to identify your transmission
  3. Go back to SSB mode
  4. Go back to full power (I forget to do this more often than I would like to admit)
  5. Tune back to where you were
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    $\begingroup$ This procedure doesn't mention identifying anywhere...? $\endgroup$
    – Kevin Reid AG6YO ♦
    Commented Dec 11, 2013 at 4:45
  • $\begingroup$ Glad I'm not the only one who forgets to go back to full power;-) $\endgroup$
    – PearsonArtPhoto
    Commented Dec 11, 2013 at 11:58
  • $\begingroup$ Once you're back on frequency, fine trim to background noise. If your "Antenna Tuner" is calibrated, build a chart of the settings for any given frequency. As you work various frequencies you will find a straight lines developing on your chart. There are daily variations caused by ground water levels and antenna length changes due to temperature changes, but your custom chart will help you get in operating range faster. $\endgroup$
    – Optionparty
    Commented Jan 19, 2014 at 1:39
  • $\begingroup$ Should one ask if the frequency is in use (in CW, "QRL?") before tuning? $\endgroup$
    – Wayne Conrad KF7QGA
    Commented Feb 3, 2014 at 18:13
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    $\begingroup$ I added an identification step to the answer above, with the assumption that the tuning process will not take longer than 10 minutes. I don't know that I've ever heard anyone actually follow this rule in practice, but it's pretty clear that they should. See e.g. exam question T1D11 or even more plainly T2A06: "What must an amateur operator do when making on-air transmissions to test equipment or antennas? Properly identify the transmitting station." $\endgroup$
    – natevw - AF7TB
    Commented Dec 16, 2016 at 4:43
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If you are concerned about unintentional interference, then you should use an antenna analyzer. Some of them actually have a mode for that whereby the analyzer sends a tone that beeps; and the closer to a 1:1 match, the faster it beeps until it is a solid tone.

Just make darn sure you don't transmit into you analyzer, or you will damage it and I can promise you this damage will not be repaired by the mfg for free.

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Other than interference issues, the key to doing this is to follow the rules about station identification.

Every transmission should be something like "VK2VXK test"

(Really, the rules say you have to do this for the first one then every 10 minutes, but I do it with every test transmission that might radiate)

When you are finished say something like "VK2VXK out"

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