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Radio Road Which tuner to get and getting the most from it. Thank God, for the radio! |
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Radio Road Which tuner to get and getting the most from it. Thank God, for the radio! |
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In Reply to: RE: thanks for the good wishes, but .... posted by JRMA on February 13, 2016 at 11:56:51:
Yes, it is possible to build 'doubled and spread' versions, and you can narrow the Rhomboid shape to tighten the pattern.Remember that only a truly directional antenna can reject multi-path.
Once you find the straight line direction between you and the transmitter, mark it on a map of your town and environs. Use a school geometry half circle compass to read off the bearing. Then print-out one of just your house on its block and mark on it the bearing. For a compass use one of the GPS based ones downloaded to your smart phone, as it won't be affected by large ferrous-metal objects.
Given the hill you need to test the 'straight-line on the map' bearing, from you to the transmitter.
Most stations use a mixture of vertical and horisontal polarities to assist car reception. So, use a ribbon T-antenna on a vertical board to find the best bearing. Then try if the same bearing is best with the T antenna horizontal.
Do remember to get away from the antenna yourself to minimise your own effects on it.
Outdoor wire antennas? You'll need to look at a book called 'Joe Carr's receiving antennas' published in the USA for guidance for wire antennas. Including earthing, static charges and lightning strikes. It doesn't have any stuff for (FM) rhombics but the principals are the same.
Local 'hams' might be a good resource.
See if you can fit it into your loft space. Because you can use indoor rated 300 ohm ribbon as the article assumes. This doubles the gain without any increase in size / area, as you then have two rhombics 'stacked.'
Rhombics are by nature wide-band-width antennas. IE the shorter the wavelength you are picking up the greater the gain. For that reason alone a loft DIY rhombic had a lot of appeal to me.
It would have covered VHF digital TV (BndIII) and FM (BndII), with lots of gain, almost no maintenance, long life, etc. Everything I want is in band II (FM) and band III DTV, all from the same mast.
But, the floor of my loft is the ceiling of the house - plaster-board nailed to timber beams - and all covered by very thick fibreglass insulation, well above the beams. So I can't see where to walk. End of that idea. :-)!
LBNL, given the hill, you might find it works better aimed up a bit, like my new VHF-DTV item is.
Warmest
Tim Bailey
Skeptical Measurer & Audio Scrounger
Edits: 02/13/16 02/13/16 02/14/16
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Follow Ups
- Have you read the article in FAQs here at AA? Print it out and read it a few times. - Timbo in Oz 14:12:27 02/13/16 (2)
- RE: Have you read the article in FAQs here at AA? Print it out and read it a few times. - Tin Ear Bob 13:36:48 04/11/16 (1)
- Yes if you have metal tanks etc in the roof that could affect any antenna up there. Foil insulation, too. - Timbo in Oz 14:51:59 04/11/16 (0)
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