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Post by Art / N4QNT on Jul 3, 2021 14:02:50 GMT -5
 For some time now I wanted to experiment with a tunable symmetrical antenna system for multiband use with minimum losses. All the old antenna handbooks always mention the Flat-Top Doublet antenna fed with Open Ladder Line using the 600-ohm spacers. I constructed this with jacketed AWG-12 stranded wire and LMR-400 coax using the tractor supply co. 4-inch fin tube insulators and 16' UV resistance Zip-Ties to construct the 600-ohm spacers. The key to this perfectly Symmetrical doublet is utilizing a continuous run of ladder-line and threading the dipole legs through each end of the apex support. So no solder points or mechanical connections at the Apex. The first connection is at the weatherized transition box outside the house where the AWG-12 and the LMR-400 coax inner conductors terminate and outer braided shields of the coax shunt together. Then routing the twin coaxes through various obstacles and 3 walls of the house that finally connect to the Balun Designs model 1171 1:1 dual core current balun that double-barrel connect to the back of the T-Network Palster Auto antenna tuner. The tuner easily matches the antenna 6 through 75-meter bands.. The block diagram below gives a great example of the installation.  |
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Post by Admin-N8SDR on Jul 3, 2021 19:35:09 GMT -5
Nice Art, I can confirm by your signal that is is working well
congrats- now how too fit this into a 42X51 foot lot....
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