Tuning and Other Problems

OK, so I have run into some problems.  I’m having a hard time making contacts on HF.

At first I was having problems on the upper HF bands with tuning and the screen freaking out.  I couldn’t tune 10-17 meters.  20 meters seems to be the sweet spot for the radio.  I was able to make one (very weak) contact to a guy in Sacramento, but that was it.  For some reason that turned out to be because I wasn’t using the UNUN. I thought I’d try without it.  It doesn’t really make sense as to why this would be a problem on the upper bands (according to the documentation), but using it made the problem go away.  The other problem with the screen freaking out on the upper HF bands was easily fixed by making sure the control cable stayed as far away from the HF coax as possible.  OOPS!

I’m still having problems with tuning the lower bands.  I can get 40 meters to tune on the upper edge of the band, but nothing lower.  I was thinking a grounding issue..which it probably is, but I can’t track it down yet.  The mount is well grounded and the body, frame and exhaust have ground straps attached.  The only thing left is to try some different coax and run a ground strap from the hood to the panel the mount is grounded to.

On a good note…everything works great on 2M/70cm.  Very clean signal, good audio…all around good reports.

I know this is a compromise antenna, but I should be doing better than this.  Any ideas?

4 thoughts on “Tuning and Other Problems

  1. Carl Reply

    While installing your Chameleon Antenna do the following:

    – Install the UNUN right under the antenna and place the 2 ferrite beads right under the UNUN and secure with electrical tape or cable ties.

    – Ground the PL-259 INPUT of the UNUN to your vehicle chassis.

    – Make sure that the antenna is as high as possible on your vehicle. The higher the better.

    – Make sure that the antenna is as far as possible to ANY metallic surfaces.

    – Create a coax choke (7 tuner of coax with about 10′ feet of coax) and place it as close as possible of the antenna inside your vehicle.

    – Do not use a mag-mount. It’s not good enough because the antenna can’t be grounded properly.

    You can join our free Forum here:

    http://chameleonantenna.com/Chameleon_Forum/

    Regards,

    Carl

    • W4DVE Post authorReply

      Thanks for the input.

      I have a short 2 foot piece of coax running from the antenna into a duplexer and the UNUN and the 2 ferrite beads are right under that.

      According to installation notes, the UNUN should be no further away that 3 feet. The chameleon dealer says he uses a duplexer, so I assume that wouldn’t be a problem. UNUN input is grounded.

      As for a coax choke, I’ve read on your forum 20 feet of coax and now you’re telling me 10. I’m not sure what’s real anymore.

      Still working on the problem.

  2. Carl Reply

    I’m not saying to use 10′, I’m saying to create a coax choke right under the antenna with 10′ of coax cable: http://www.n0ew.org/StrangeAntennas/k0s.coaxchoke.html A coax choke is different thing of a coax feed line. THe feed line is minimum 20′ (coax from your tuner to the antenna) but a choke is a coil of coax attached right under the antenna to prevent RFI.

    Remove the duplexer and make sure that the antenna works without it. Closer will be your UNUN from the antenna and better will be the results.

    Concentrate on the frequencies 10M to 20M first and after that 40M to 80M. Now depending of your antenna installation 80M will be the toughest band to work. The 80M band operators are usually using several hundreds of power for their stations.

    For more ideas join the forum.

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