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8009RE: Re: [RADIOSHACKDX394] Better antenna

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  • josephrot
    Oct 13, 2013

      In the world of DX-394...

      What would be generally sublime if only we all had room, both vertically and horizontally, would be what we sometimes humored others at NASA with...


      The One-Fifty Principle...

      An antenna 150 ft long, strung 150 ft high, via 150 ft twin towers, fed with no more than 150 ft of RG-6 coax...

      Not too surprisingly, with the HF usage range back then, late 60's into early 70's, the "principle" worked very well receiving when put into action, be that surprising or not --  regardless of the Law of Resonance, or what any of the "antenna elite" felt would happen.

      It also happened to perform quite satisfactorily on transmit as well, with few if any complaints, and interestingly low SWR as well.

      Wouldn't work well, you say ?  Tell that to the comm operators and crews that used it every day and night, and got the receive / transmit job done for many years.

      If only we all had the space...

      Joe Rotello / Knoxville, TN / USA


      ---In RADIOSHACKDX394@yahoogroups.com, <radioshackdx394@yahoogroups.com> wrote:

      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...
      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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