Antenna tuner won't tune

[KJ6TSX]

I am having trouble getting my antenna tuned, I have a antron 99 antenna set up for 27mhz, I am using a MFJ 949e antenna tuner. I would like to match the antenna for 40 and 80 meters. I have downloaded and read the tuner manual.

I would assume that when you change the inductor on the tuner it should change the swr?? mine stays steady at 1.5 in SSB I get better results when I tune in CW, something also interesting I have to adjust the antenna and transmitter dials to get the SWR down to 1:1 when using the dummy load. My rig is a Kenwood TS130s

Not sure what I am missing??
Thanks for all the Help
George

[LA1BRA]

Your antenna is way to short.....you might read over some of the SGC tuner manuals for some reference reading, They are free on the SGC website, lots of useful antenna and tuner info... You would do better stringing out a long wire fed against a ground system for any kind of performance..or a loop, many options out there

73 de LA1BRA / Kb5vwz tom

[KJ6TSX]

I know my antenna is short, only 18 feet high Buttttttt thats why I got a antenna tuner<GRIN> Should I be happy with the 1.5 match? in till I can get a better antenna? What antenna should I be dreaming about?
Thanks
George

[WX7G]

1.5:1 is fine.

[KB1GTX]

The a99 has a coil to ground that's about 1/2 inch dia, and only a few turns,, would not that just about short out the circuit as far as an antenna goes for 4mhz?

[WD259]

Congrats on your new ticket!  Read up on antennas, the 99 will do ok on 10 and 12 meters, poor on 20. build a di-pole, as long as you have room for and go from there. Look around for a local club if possible.  The antron is pretty much worthless on 40 and 80,

73, KD8GEH

[VE7REN]

i too use the a99 . it works great on 10/11/12/15/17 meter,but wont work on 40/80. its not designed for this. build a wire antenna,and you will be surprised what you hear.

[G8JNJ]

Hi,

Well done on getting your licence. As you are now finding, it's only the very first step in a very long voyage of discovery 

The A99 is not just a length of wire in a plastic tube. It has a rather complicated matching section built into it's base. Which is optimised to obtain a good 50 ohm match on 28MHz. As you try to use the antenna on frequencies that are removed from the design frequency of the matching network. A greater proportion of the RF energy you apply to the antenna will simply be generating heat somewhere in the system.

When you attach your tuner to the antenna via a length of coax. You are trying to match the whole antenna system, including the coax to something like 50 ohms so that your rig is happy. When operating on 40 or 80m. The coax will be severely mismatched at the antenna end of the cable. Which will result in a significant amount of power being lost as waste heat in the cable.

As a rule of thumb if you measure a SWR of greater than say 5:1 (and certainly when 10:1) at the rig end of the coax without a tuner. Then adding a tuner at the rig end  is not the way to go. Even though it may make your rig happy. You will not be radiating much power from the antenna, as most RF will be generating waste heat somewhere.

Try hooking up a 10 or 20m length of wire to the random wire input on your tuner. And find out what you are missing on 40 & 80m.

As long as your rig is happy, don't agonise about an SWR of better than 1.5:1. It's really not going to make that much difference.

Regards,

Martin - G8JNJ

www.g8jnj.webs.com

[K9YLI]

 No one else has noticed the little blurb..   difference  in tuning in  ssb  or  cw..

you always  have to  tune  in  CW  mode as you need a steady  carrier  to have indication on the meters..
or    am or  flm  works as both  provide steady carrier..

SSB  and  whistling or what ever,, is way  to random to see a good  meter indication..

[W5DXP]

... mine stays steady at 1.5 in SSB ...

Does it stay steady when you do a long loud whistle into the mike? SSB doesn't put out any power unless modulation is present so the SWR meter won't work unless modulation is present.

[N4NYY]

I am having trouble getting my antenna tuned, I have a antron 99 antenna set up for 27mhz, I am using a MFJ 949e antenna tuner. I would like to match the antenna for 40 and 80 meters. I have downloaded and read the tuner manual.

No chance in hell. I have an Imax 2000 which tune well 10-15M, and then struggles on 17M, but will still tune. But that is about it. Being that the A-99 is shorter than the Imax, it may not tune on 17 at all, or may tune better if it is a harmonic. But I am not positive because I am not really familiar with the A-99.

But in all likelihood, you are looking at 10-15M.

[N4NYY]

BTW, in CB circles, the effort to attain a perfect 1:1 match is almost contagious and mandatory. This is about the biggest waste of time anyone can have. I would sign on the dotted line right now, if I could get matches of 1:5 on most bands. You have to go over 2:1, just to get passed the 10% power loss territory. 1:5 power loss is almost negligible.

[WB6BYU]

You have to go over 2:1, just to get passed the 10% power loss territory. 1:5 power loss is almost negligible.

I presume you mean 1.5 : 1 rather than 1 : 5.


An SWR of 1.5 : 1 is fine - it is rarely worth improving any beyond that.  But if you can't get the SWR
to go any HIGHER than that when you turn the inductor switch, something is wrong.

Do you have the tuner switched to BYPASS or DIRECT mode?  Actually, if the SWR is constantly
1.5 : 1, I'd guess that you have the tuner switched to the internal dummy load, which also bypasses
the tuner.  Perhaps the knob on the switch has shifted?  The SWR on the coax is going to be very
high - I expect it to read over 10 : 1 (and that low only due to losses in the coax) if you aren't
going through the tuner.

Are you reading the SWR meter correctly?  Does the output power on the meter vary when you
adjust the tuner?  Or when you change the output power on the radio?

Are you using a constant carrier mode (CW, FM, AM, RTTY) when adjusting the tuner?  It is possible
to do it on SSB while making noise into the mic, but it is much easier with a constant carrier.


Two things in summary:  first, if the SWR reads low (1.5 : 1) all the time, you aren't connected
to the antenna you describe through the tuner.  Something is wrong.

Second, just because your tuner can match the coax in the shack doesn't mean that an antenna
will work.  The losses in the coax and/or the tuner will eat up most of your power.  You'll probably
get better signals by connecting the coax shield to the single wire output of the tuner and using
the feedline as the antenna than with the antenna fed in the conventional manner.

[N4NYY]

I presume you mean 1.5 : 1 rather than 1 : 5.

Yes.

[AD6KA]

Hi George:

Why don't you measure the dimensions
of your yard/available space, and maybe we can
give you some ideas for some inexpensive
wire antennas. (Yes, you CAN run wire antennas
through tree branches without appreciable
decline in performance).

For some interesting reading about how your
Antron works,and is effected by feedline isolation
and mast height, check this out:
http://www.w8ji.com/end-fed_vertical.htm#IMAX
Yes, I know it says "IAX" in the URL but Tom
also discusses the Antron 99 in that article.
(Similar antennas anyways)

Just about any wire antenna
of decent construction will out perform the
Antron, especially on the low bands.
A good antenna book is always a good investment
and will be useful for years to come.
(The laws of physics don't change, but your
QTH might.....)

Do you have an HOA or anything that limits
antenna height?
Good luck with your low band antenna project.
73, Ken  AD6KA