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Last night was my first night on the air as a General licensee and at HF. I've got an IC-7300 with the built-in antenna tuner. I'm pretty sure I understand how to operate the radio, for the most part.

My antenna is an MFJ-1625. It's one of those telescoping apartment window whips with a big coil and an alligator clip. It has a tuner mounted on it also. Problem is that I can't reach the dang thing where I'm deploying it out on the deck. I'm fairly certain that the 12 foot whip will be verboten the first time management sees it. Anyway, after I figured out how to read the SWR, it seemed pretty close to 1:1 but that is reading it from the transceiver, of course. I was able to listen to AM radio stations without much trouble. I didn't hear much of anything on other bands though although there were spot sources of RFI. Of course, having found an RF source, I would naturally cycle through the modes to see if I was just in the wrong mode.

Note that my brother is a Ham up in the thumb area of Michigan and I live near the Ohio river. We were unable to reach each other regardless of the tricks that we tried. He is checking his gear as he hasn't hammed it up in quite a while.

Now to the question. I was thinking of replacing the antenna tuner on the whip with an automatic one such that I don't need to reach it, but reviewing the options in the market so far, and looking at what specific antenna tuners's appear to be designed for, makes me think that maybe a whip doesn't need two tuners, one at each end of the transition line. Is this the case?

Request enlightenment.

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It is not normal to have and use tuners on both ends of a feed line.

The purpose of an antenna tuner is to provide an adjustable impedance transformation. The reason we want that transformation is so that the transmitter can work into the (usually) 50 Ω load it was designed for.

  1. If you have an antenna tuner located (only) at the antenna, then this is the ideal condition; the transmitter transmits onto the matched-by-design feed line, and the tuner transforms that impedance to the antenna's feed point impedance.
  2. If you have an antenna tuner located at the transmitter, this is usable but results in additional losses, because the impedance of the feed line does not match the antenna, so the transmitted signal reflects off that mismatch, and reflects back and forth (standing waves), losing some power to the resistance of the line each time. This can be a good compromise when your feed line is short, or made of a low-loss type of line such as ladder line.
  3. If you have antenna tuners in both locations then at a minimum you have unnecessary components (which all add some loss to the system), but it's also likely that you're unnecessarily mismatching with the line and adding standing waves to the system (more loss).

In your case, you have an antenna and a transmitter with built-in tuners; therefore, the ideal approach to using this system would be to set the tuner built into your radio in bypass mode, and use only the tuner at the antenna (case 1 above). This is also the case if you buy an automatic or remote-controlled tuner to install at the antenna — the best configuration is to use that tuner only, and set your radio's tuner to bypass mode.

If you do not get a remote controlled tuner and your antenna is positioned such that you cannot practically adjust the tuner at the antenna when operating, then using tuners at both ends (case 3 above) makes some sense; the one at the antenna can be set to give the best match feasible over the entire range you want to use and the one at the radio can be set for the frequency you're actually using at the moment. But that's a compromise, and it could be improved on by using a fixed matching network at the antenna, designed once and left in place, rather than a tuner whose adjustable components aren't being used. If you do this, make sure to adjust the antenna's tuner with the radio's tuner bypassed, or with a separate tuner; otherwise you're not getting the best match with the feed line.

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  • $\begingroup$ I'm using LMR-400 and the line is only long enough to reach from one room to another. I can remove the tuner at the antenna, easily. So, I would put in a fixed matching network and then tune it without the IC-7300 tuner but would I then use the tuner after tuning the matching network? $\endgroup$ – NonYaBidnezz Jan 20 at 21:44
  • $\begingroup$ @NonYaBidnezz If you use a fixed matching network, then you have to use the tuner in the radio to make up the rest of the matching. It sounds like you've got a good situation for that (short feed line, though coax is not as good as ladder line for unmatched use). However, with the MFJ-1625, the tuner also contains a balun, so if you choose to remove it, you would need a replacement balun. I recommend keeping the tuner and just setting the L and C controls either to the lowest available values, or those that make a good match on your favorite band. $\endgroup$ – Kevin Reid AG6YO Jan 21 at 1:26
  • $\begingroup$ The chief concern about the feed point tuner is that it is outdoors but not designed for outdoors. It's reasonably safe on the deck for now, I think, but it will have to be replaced eventually regardless. $\endgroup$ – NonYaBidnezz Jan 21 at 14:23
  • $\begingroup$ "a low-loss type of line such as ladder line" or decent coax, like Times Microwave LMR-400, which has loss similar to typical 300 or 400 ohm ladder line. $\endgroup$ – Phil Frost - W8II Jan 24 at 17:16
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First, I'd say that using both the tuner for the antenna and your built-in antenna tuner probably didn't hurt anything, but was most likely unnecessary. You would have a bit more efficiency if you put your internal tuner on bypass. Of course if you adjusted the whip's tuner at a particular frequency, and then changed the frequency, then you might have had higher losses that were somewhat disguised by the 1:1 SWR you saw.

Your antenna is not very efficient for transmitting, and the lower the frequency gets, the worse the problem becomes. The counterpoise wires are essential for getting the most out of a monopole antenna, so I hope that you had them installed.

You didn't mention what band you were on, but it's possible that you were inside each other's skip zone. The closer your frequency is to the maximum usable frequency (MUF), the longer the skip zone is. I've had the skip zone extend out a couple hundred miles or more at night on 40m.

I'd recommend enlisting help from someone at the local ham club. You could try a contact with your brother from a station with a known-good antenna, which would help explain if your problem is just propagation and noise; or propagation, noise, and the antenna. If you can't find an experienced ham to help, you might try a different antenna, such as a dipole hung in the trees of a local park. (Best to inform the people in charge of the park of your intentions beforehand.)

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    $\begingroup$ Counterpoise was installed. $\endgroup$ – NonYaBidnezz Jan 20 at 21:50
  • $\begingroup$ Well, my brother is a 20 year Air Force radio professional (retired) so I was pretty comfortable with him as Elmer. You're right though. I do need to join a club since he lives in a different state. $\endgroup$ – NonYaBidnezz Jan 20 at 21:51
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    $\begingroup$ You just have too many variables, and you need to eliminate some. Another ham in the same town could be a big help. Your brother can still be your Elmer ;) $\endgroup$ – rclocher3 Jan 21 at 22:34
  • $\begingroup$ Living in an apartment where they limit what I can do, is the most obvious. I couldn't, for example, put an antenna on the other side of the building. Fortunately I do just barely have an angle on Due North which is roughly the right bearing. ...and, of course, there's another building there. $\endgroup$ – NonYaBidnezz Jan 22 at 10:13
  • $\begingroup$ I feel for you, that must be frustrating! You might think about stealth antennas (any trees near your balcony?), and operating portable or mobile. Lots of other people are in your boat too. $\endgroup$ – rclocher3 Jan 22 at 16:52
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AS A HAM FOR 59 YRS, 1. BYPASS THE INTERNAL "TUNER", AND USE A MANUAL (MATCHBOX, TRANSMATCH, COUPLER ETC) BOTH THE BOX ON UR DESK AND / OR THE ONE BUILT INTO YOUR RIG ARE NOT, ARE NOT, ANTENNA TUNERS. WHEN YOU CUT A DIPOLE FOR 7.25 MHZ AT 64.55' YOU HAVE "TUNED" THAT ANTENNA. CHANGE YOUR FREQUENCY, YOU MUST CHANGE THE LENGTH OF YOUR DIPOLE. - THATS TUNING. THE INTERNAL TUNERS OR BOXES WITH DIALS AND SWITCHES LABELED AS TUNER, ARE BOTH ANTENNA MATCHING DEVICES (TRANSMATCH OR MATCHBOX). THEIR JOB IS TO ACCOMODATE THE IMPEDANCE LOAD GIVEN TO YOUR TX BY THE ANTENNA (AND THIS IS IMPORTANT) "SYSTEM". REMEMBER MAXIMUM POWER TRANSFER OCCURS WHEN ZL = ZS. PERSONALLY I USE ONE TRANSMATCH, AND ONE SWR BRIDGE BOTH AT THE TX END. ONCE YOUR ANTENNA IS PROPERLY TUNED. - THE RADIATING ELEMENT IS RESONANT AT THE DESIRED FREQUENCY, CHANCES ARE SLIM YOU ARE GOING TO RAISE AND LOWER, ADD AND SUBTRACT LENGTH. YOUR GOING TO MATCH THE CHANGE IN IMPEDANCE TO YOUR RIG. '73 AND GL KF9F

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  • $\begingroup$ Kindly do not use ALL CAPS, as it's difficult to read and is commonly taken as angry shouting. Also, this does not answer the original question. Please take a few minutes to read the tour. This site is different from a chat-style forum; This site is all about getting answers. It's not a discussion forum. There's no chit-chat. $\endgroup$ – Mike Waters Jan 22 at 21:17
  • $\begingroup$ 1. I can't use a dipole. I live in an Apartment. 2. Fair point about tuning vs matching. 3. I'm a software developer. I'm used to automating away the manual stuff. It's literally my job. ;-) I've a few coins to rub together so I'll probably just get an automatic one. Further, the matcher isn't designed for outdoors and MUST be replaced anyway. $\endgroup$ – NonYaBidnezz Jan 23 at 10:08

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