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Antenna Tuning - Rules and Ethics

Discussion in 'On-Air Operations - Q&A' started by KM4LDX, Jan 22, 2017.

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  1. KM4LDX

    KM4LDX Ham Member QRZ Page

    Well, we hear it all the time in CW form. We'll be in a conversation and hear a faint but consistent CW key in the background. Sometimes it's on frequency, others it's in the background. Sometimes it's flat out annoying, particularly when it comes out of nowhere unexpectedly. I have a dipole that I use on multiple bands, connected to an antenna tuner. When I change bands, I need to tune my antenna to the new band, but I want to do this in a way that is within legal parameters and so that it doesn't affect others in a negative way. It seems that there's no way around having to tune an antenna this way, unless one owns other expensive equipment I suppose.

    Would this be within legal and ethical means prior to transmitting during this process?

    1) Check to see if the frequency is in use, either by means of CW or phone.
    2) If all clear, send out the call sign of the station performing the tuning, either by CW or phone, before and/or after transmitting.
    3) Transmit on the lowest power setting, unless more fine tuning is necessary.
    4) Carry it out in as little time as possible.

    More often than not, at least when I'm listening, I hear this tone without the station identifying themselves. It's very common, but seems that technically doing so goes against FCC guidelines. As far as checking to see if the frequency is in use, this seems more of a common courtesy, but even in doing this, sometimes I imagine the tone will bleed over to other frequencies. Instead of using CW, would a silent AM keying be more acceptable? The lack of tone may seem that way, but then more bandwidth is being used, potentially causing a more widespread disturbance.

    There are different opinions out there, so I just want to be clear on the proper procedure for carrying out this process. Thanks in advance.
     
    AI3V and AL4Y like this.
  2. K7MEM

    K7MEM Ham Member QRZ Page

    The tone that you refer to is generated within the receiver. It doesn't make any difference whether you are keying in CW or silent AM. Both produce a carrier, which, when it is offset from your receiver's BFO, generates a tone. As long as there is not modulation, the AM carrier alone doesn't use any more bandwidth than the CW carrier. Another tone may be generated, due to the close proximity of two signals.

    I use a manual tuner. With each of my antennas, I have checked the tuner settings with a antenna analyzer. I then have a record of the approximate settings for each band. I also check the 2:1 SWR band limitations, for each of the setting. That tells me how far I can stray, without the need to re-tune. Sometimes there are two settings per band. One for the low end and one for the high end.

    When I change bands, I can then set the tuner very close to the final value, without ever generating a carrier. Sometimes the tuning is broad enough so that I don't have to tune any further. And, on some bands, the tuner isn't needed and I switch it to bypass.

    When I need to do some extra tuning on a band, I reduce my power and find an empty spot near the frequency that I want (+/- 10 KHz). I then tune up there. When I am done, I move to the spot I want to be. Tuner settings are usually broad enough so that I don't need to tune every time I move around a section of the band. The exception to this might be on 80 or 160 meters, but I don't use those bands very often. On the higher frequencies, there is usually no need to re-tune as I move around a small section (+/- 50 KHz) of a band.

    For tuning purposes, all you need is enough power so that your SWR bridge gives you a reliable reading. Usually that is just enough to get a full scale reading in the FWD mode.

    I have never used an auto-tuner. So someone with a auto-tuner might have a different method for tuning up and keeping interference at a minimum. Maybe some day I will put away my stone ax (manual tuner) and try a auto-tuner (If I can get one cheap at a ham fest).
     
    N4AWP and WG7X like this.
  3. KE0CAA

    KE0CAA XML Subscriber QRZ Page

    I think the biggest issue is that in order to perform step 1 on your list you are transmitting and without tuning up you very likely could be damaging your rig by transmitting into a high swr. Most common courtesy that I have heard regarding tuning is to tune to an open frequency (listen for a minute to see if it's in use) and then using the lowest power that your tuner will tune up. Of course the problem with any of this is that your antenna may be a bit on the deaf side in comparison to the contest station with the big beam pointed in your general direction. You may not hear anyone else there but they certainly will hear you when you go to tune. Unfortunately this is a situation that is nearly impossible to avoid.
     
  4. KM4LDX

    KM4LDX Ham Member QRZ Page

    I've been looking into auto tuners, need one that'll work well with an IC-735. I'm open to suggestions if anybody knows of one. I like the MFJ models, but my particular radio doesn't appear to be on the support list.
     
  5. AA7EJ

    AA7EJ Ham Member QRZ Page

    All valid points with one note to add - you are assuming that amateur radio hobby is limited to making contacts.
    And since you have mentioned "rules" - check out something about "amateur is progressive etc etc. "
    There are amateurs who are experimenters, do not necessary have means to meticulously scan the frequency for "59 QSL" in progress.
    And there is this thing called "propagation" - just because you can hear them doesn't mean they can hear you.

    Yes, tunning 10KW amp full tilt is annoying, just think about the offender's KWH meter spinning.

    However, HF in not and ever will be same as 2 meters FM full quieting repeater "contact" which seems to be the underlying motive of your post.

    Am I wrong?

    73 Shirley
     
    WA0MNA likes this.
  6. K7MEM

    K7MEM Ham Member QRZ Page

    I use a IC-735 with a manual tuner. According to the manual, there is the ICOM AT-150, AT-100, and the AT-500. You might be able to find one in the QRZ or eHam.net swap meet areas. Possibly even eBay, but I would avoid the ones that are listed as untested. But I am sure there are other auto tuners out there that will work with the IC-735. Any one you choose should be able to interface with the rear ACC-2 connector, which contains band information.

    But, don't be so fast to abandon your manual tuner. If you have recorded the manual tuner's settings for each band, its easy to switch from one band to the other. A little fine tuning, after checking the band, and your ready to go.

    It has been said that auto tuners tend to have smaller ranges, then manual tuners. One of my antennas is a 92' End-Fed, with a 9:1 Balun at the feed point. With my manual tuner, I can tune all bands down to 1.2:1, or lower. I don't know if that would be possible with and auto tuner. But, I can't confirm that, because I never owned one.

    FWIW, I reread your original post and didn't see any underlying motive.
     
  7. AG6QR

    AG6QR Subscriber QRZ Page

    I think it would be legal and ethical, though your first step, while seeming polite, might actually end up causing more interference than it saves. Also, transmitting ID before tuning is not legally required, nor is it required by protocol, since you're not expecting a response. Transmitting ID after tuning is complete is required by 97.111, though I sometimes hear stations omit this.

    The legal requirements are:
    1. Avoid intentional interference (97.101(d))
    2. Be brief (97.111(b)(1))
    3. Use the minimum power required to accomplish the goal (97.313(a))
    4. ID your transmissions (97.111)
    5. Operate in accordance with good engineering and good amateur practice (97.101(a))
    I think the ethical considerations are pretty much the same, mainly to be careful to avoid interfering with anyone else.

    I use an antenna tuner which can match the antenna quite a bit quicker than I can transmit "QRL?" in CW or "Is this frequency in use?" on voice. I also use low power for tuning, typically one watt. So I check if the frequency is in use merely by listening for at least a couple of minutes before tuning. Transmitting and waiting for an answer would be more disruptive than the actual tuning process. Also, when I'm at one watt, it's unlikely, though admittedly not impossible, that I'd be an "alligator" who would cause problems for someone I couldn't hear.

    With that in mind, my process is:
    1. Check to see if the frequency is in use, by listening. Tune to an empty frequency as required (my tuning frequency might be a few tens of kHz away from where I eventually want to end up communicating). If I'm using my manual tuner, then get it close to correct by using the manual controls to peak the noise received during this step.
    2. Transmit a steady 1 watt carrier for a couple of seconds to tune.
    3. Transmit "DE AG6QR" in CW at the same low power level to comply with 97.111.
    If my purpose in tuning up is to get ready to call CQ on that same frequency, I might skip step 3 and go straight into my CQ procedure. That is, turn up the power, transmit "QRL?", wait, repeat, then transmit my CQ, including my call sign.
     
    KC8VWM likes this.
  8. N1BCG

    N1BCG Ham Member QRZ Page

    I adjust a manual tuner by using a home-made (simple) impedance bridge and about 50mW from a VFO. The bridge compares the antenna to a known 50Z resistor and displays the relative difference with a voltage on a sensitive meter. The tuner is adjusted for minimum meter deflection:

    [​IMG]

    The antenna to be tuned and matcher are connected to "X". A non-reactive 50Z load is connected at "Reference". I used all 1/4W resistors at this power level. "Generator In" is where the VFO connects. You could also pad your rig's output waaaay down.

    The VFO and bridge are connected via a switch to the tuner/antenna as if they were a rig. The receiver is set to the operating frequency and the VFO / bridge are switched on line. The VFO is set to the operating band and frequency with a zero beat and the tuner adjusted for minimum meter indication (the SWR meter on the tuner doesn't deflect at all, even in forward, with this little power). Once tuned, the antenna is switched back to the rig to be used.

    This is a magnificently useful circuit for experimenting with antennas. A poor null can also indicate that your VFO is outputting harmonics.

    The bridge works by splitting the RF signal into two paths that are electrically identical when the antenna and 50Z reference resistor present the same load on the circuit. Any imbalance is rectified by the diode and displayed on the meter.
     
    Last edited: Jan 24, 2017
    W4KJG likes this.
  9. W4KJG

    W4KJG Subscriber QRZ Page

    I do something quite similar to what N1BCG described above.

    I have several old Palomar noise bridges. One is dedicated to my homebrew L-network tuner through a bypass switch to whatever right I'm using.

    [​IMG]

    The one dedicated for this purpose is powered with a wall wort power supply. It is always turned on, but is bypassed except when changing bands. I keep it set for Z=r50 ± j0. My bypass switch is a spring loaded push button DPDT switch, so the bridge is in the normally bypassed mode except when setting the tuner.

    All I have to do is set my transceiver receiver to the desired operating frequency, push the bypass button, and listen for a minimum of noise in the receiver when I fine tune the matching network. As others said above, I know settings that get me very close on each band.
     
  10. NI4TG

    NI4TG XML Subscriber QRZ Page

    An LDG auto tuner (like the z100) will work great with your rig. You do not have to be on the exact frequency of a conversation in progress to tune. Also, after a little use, your auto tuner will work in the blink of an eye. After a few times of tuning, an amp can be set to noted settings for a given band/frequency.

    Operators who tune for a long time in a current conversation or contest are just plain annoying. My two cents.
     

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