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Author Topic: Tuning problem  (Read 11372 times)

AD5QA

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Tuning problem
« on: March 07, 2004, 01:34:20 AM »

I have a TS440 mobile with the Hustler RM80 cut to the mars frequency. The transceiver seems to have problems as if it had a bad ground. While using the tuner (internal) the swr meter waves, just like stray capacitance in the line.  I can jump to 80 meters and 40 meters and tune the antenna up just fine. Even though it has been cut to that frequency, just tells me the tunner is working even if I may be putting out 1.5 watt from the antenna. Dont care just want to tune the rig to that frequency.  I know I really need an swr analyzer but dont have one, would rather geta carolina cyclone screwy antenna. Any suggestions?
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N3ZKP

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Tuning problem
« Reply #1 on: March 07, 2004, 10:47:16 AM »

First off I would guess that you DO have ground problems, either with the rig or more likely with the antenna.

The second thing is Hustler coils are notorious for narrow bandwidth on 80m and I seriously doubt you are going to get it to load outside 80m.

What is the exact frequency you are trying to load? Please use the standard three-letter identifier.

Lon - NNN0OOR
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AD5QA

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Tuning problem
« Reply #2 on: March 07, 2004, 12:12:42 PM »

Hustler sent me a cutting chart and I had to cut the antenna almost in half.  The frequency is KCE.
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N3ZKP

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Tuning problem
« Reply #3 on: March 07, 2004, 03:25:35 PM »

<< The frequency is KCE.    >>


@#$%^^&! Forgot that Army has different identifiers. Now I have to dig out my copy of the Army matrix. <g>

I'm still betting on both a ground problem and that antenna not wanting to resonate that far out of band, even with trimming. On 80m good grounding is a must. It's also possible you are going to need some inductance across the feed point.

Lon NNN0OOR

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AD5QA

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Tuning problem
« Reply #4 on: March 07, 2004, 08:18:06 PM »

I will check it out again, I did add a 240 pf mica across it dosen't help any that I noticed. I need to find someone with an analyzer, I wonder what the resonate freq is? Of if it is even close.  I will have to add more grounding or maybe check my connections again.  
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N3ZKP

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Tuning problem
« Reply #5 on: March 07, 2004, 08:42:32 PM »

<<  I did add a 240 pf mica across it dosen't help any that I noticed. >>

More than likely you need _inductance_ rather than capacitance across the feedpoint.

I agree you need an antenna analyzer. It is next to impossible to prune an HF antenna without one.

Just to make sure I understand you, are you pruning the coil or the whip? I seriouly doubt that yhou can make the whip short enough to make the coil resonate that far above 57m.

Lon NNN0OOR
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AD5QA

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Tuning problem
« Reply #6 on: March 07, 2004, 09:20:55 PM »

The whip, I agree; I was/am trying to take an easy way out. But, with HF mobile there is no such thing.  I was looking for a simple coil for inductance at a recent ham fest, didn't find one.  I was goung to emmulate one with a transmatch / versa tuner gear but didn't find one also that was decent.  Before I spend lots I think I will just save and invest in a screwdriver antenna, that way I will have freq agility. I checked over my ground and it looks good, radio grounded with 6in cable, engine grounded to the frame with factory ground of 4in. Antenna grounded to roof/back hatch with 5in cable. I still have some to go but should be ok, Ham Bands have no problem.  

This really buggs me, I have to sign up with something and can't seem to get my stuff togeather. It's been 3 months.

Thanks for your help, any other ideas I am wide open.

Thomas Jenkins
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N3ZKP

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Tuning problem
« Reply #7 on: March 08, 2004, 11:18:41 AM »

Thomas:

I think you'll find the motorized antenna is a much better arrangement. I switched to a High Sierra 1800Pro last year and couldn't be happier. I highly recommend it over the "clone from Carolina" - better constructed, better looking, etc. :)

Although most of the manufacturers have "baby" versions of their motorized antennas, I haven't any personal experience with them. Look long and talk to lots of folks who own the antennas before you plunk down a big piece of change.

Good luck!

Lon
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N3ZKP

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Tuning problem
« Reply #8 on: March 08, 2004, 11:20:57 AM »

<< I have to sign up with something and can't seem to get my stuff togeather. It's been 3 months. >>

Are you trying to do it strictly mobile - no home station?

Lon NNN0OOR
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K8KAS

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Tuning problem
« Reply #9 on: March 08, 2004, 12:51:03 PM »

I think you missed the point, all of your problems point towards a poor or bad RF ground. Is the rig grounded to the car body(inside the car) and the coax shield at the antenna connecton grounded as well. The antenna connection (shield) may need to be jumpered to the car body, sometimes the bumpers connection to the car body is not a good one.
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