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8007Re: [RADIOSHACKDX394] Better antenna

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  • Tom Holden
    Oct 13, 2013
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      What you accomplished is a solution I have advocated over the years, i.e., a smallish antenna as high and in the clear as you can get it, fed with shielded transmission line, shield grounded at entry to premises. I’m not sure how to characterise the behaviour of your 2m antenna at hf. It is certainly small. The tee-match makes a very small loop – maybe 13 inches shy of being a short-circuit; the rest of the 2m dipole might act as capacitive stubs. Ideally, the feedline is not acting as an antenna but it may well be. If not, then the antenna is nicely removed from local interferers.
       
      Another cause for it being apparently quiet is that it is just a very small antenna, compared to your 150’ doublets, and does not pick up nearly as much energy across the spectrum but especially so at lower frequencies. In other words, it is acting as an equalizer. This can have the added benefit of reducing the risk of receiver overload and the consequent internal generation of many intermodulation products raising the background noise level.
       
      I don’t think I would design an hf antenna with such a small loop – I daresay it will not pull in upper hf signals as well as a larger antenna but if you’re happy with it...
       
      Tom
       
       
      Sent: Saturday, October 12, 2013 9:51 PM
      Subject: [RADIOSHACKDX394] Better antenna
       

      I was trying to come up with a better lower noise antenna for my DX 394. I drew several ideas out on paper and found them unsatisfactory. I thought what what can I do. Then I remembered that I had a set of 4 element 2 m Boomer beams up. I disconnected all the coax from the back of the 394 and hooked up the Boomer beams to the so235 on the back. Much to my surprise the 2 m beams were very quiet and really pulled in the signals. Ernie

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