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Author Topic: can you FINE TUNE (w/tuner) a OCF antenna????  (Read 2503 times)
KC8Y
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Posts: 496




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« on: November 15, 2015, 06:33:42 AM »

Just need information:

My antenna is a Buckmaster OCF that works on 80, 40, 20, 17, 12, 10 & 6m (never operate on 6m).

Is an OCF antenna able to be FINE TUNED (w/tuner) for/on the mentioned bands???

I operate QRP power levels [less than 5watt] and require every watt out.  Thank you

Ken KC8Y

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DL8OV
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Posts: 801




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« Reply #1 on: November 15, 2015, 06:44:36 AM »

An antenna tuner can be used on any type of antenna from verticals and yagis to OCF dipoles and long wires. Please remember however that the most efficient place for any tuner is at the antenna end of the coax, that way there will be 50 ohms at both ends of the line.

If every fraction of a watt is important then the best option is a series of resonant dipoles fed with ladder line.

Peter DL8OV
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KC2QYM
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Posts: 875




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« Reply #2 on: November 16, 2015, 08:27:13 AM »

Any well designed multiband antenna has resonnant SWR dips somewhere within each band.  After that you have to use a tuner when you change frequencies outside of resonance.  I don't get the nature of your question; do you understand antennas on the basic level?  As you bought this antenna and did not build it, you missed an opportunity to learn something about antennas.  Had you built it you would probably never ask this question.  Please read the ARRL publications related to antennas, SWR, resonance, etc. because this will help you understand what is happening under the covers.  Build yourself a simple mono band dipole and experiment a little...it won't hurt.
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WE1X
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Posts: 537




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« Reply #3 on: November 19, 2015, 06:17:15 AM »

Just need information:

My antenna is a Buckmaster OCF that works on 80, 40, 20, 17, 12, 10 & 6m (never operate on 6m).

Is an OCF antenna able to be FINE TUNED (w/tuner) for/on the mentioned bands???

I operate QRP power levels [less than 5watt] and require every watt out.  Thank you

Ken KC8Y



Ken,

I've been using a Fridzel FD-4 OCF 80-10m dipole for almost 20 years. Great antenna.  SWR varies a bit by band (80, 40, 20, 17, 12, and 10). Yes, I use a tuner to "touch-up" some bands like 80/75m with no problem. Although the antenna is nowhere resonant on 15m I use a tuner for that band and it works just fine.  Although rated at 2kw I seldom use more than several hundred watts, but generally 50-100 watts.

Harry WE1X
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K9PHT
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Posts: 79




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« Reply #4 on: November 24, 2015, 06:13:42 AM »

I have the Buckmaster OCF antenna here that works on 75/80M and use it for the house. I have a second older portable OCF Antenna as well to use with my OFF-ROAD POPUP trailer set. I also have one of those real small mobile type MFJ antenna tuners - can't remember the model number...

I use the MFJ962D and also the MFJ941D antenna tuners here with it.

I like the 962D with its roller inductor that matches anything.

Of course for me all of this is only making the transmitter happy and probably has nothing whatsoever to do with changing the performance of the off-center antenna.  When camping OFF-ROAD the roller inductor is great as my OCF antenna is about 15-feet high at the center pole and gets throwed up into the trees on each end.   I used it on 75M ham bands mostly and liked to be able to check-in with the Navy MARS HF frequencies when they was still operational...

Roy Ken
k9pht - King George VA

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KC8Y
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Posts: 496




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« Reply #5 on: November 24, 2015, 06:48:23 AM »

Thank you, all for your comments

My OCF is a Buckmaster (covers 80/75; 300watt balum), and my rig is an IC-7200 [run about 40watts] & tuner is MFJ-945E.

Will try 30 and 15 meters, next

Ken KC8Y
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