Icom R-75 Antenna Help

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cmed325

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I currently run a Icom R-75 ,Im using a wire antenna located in the attic,However i want to really wake up the reception by mounting an outside antenna,Any recomendations? I Have an HRO store nearby.
 

jackj

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Decide which bands you want to monitor then put up resonate antenna(s) for those bands. If you have to room then I would recommend half-wave, center fed antennas. You could use a single feed line and arrange the antennas fanned out from the feed point.
 

ka3jjz

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That's one approach, though a bit land-intensive. cmed, how much room have you got to work with? Any trees that can serve as supports? Any nearby power lines (which we want to strictly avoid)? Any particular points of interest (hearing a particular part of the world, for instance)?

The above questions will help narrow down your design possibilities. While a lot of people start with the very popular Par EF-SWL (and there's certainly nothing wrong with this), there are numerous other designs. You're in a good position to get a lot of interesting stuff - there were several top DXers in the area that I knew from living there many years ago.

Mike
 

wbswetnam

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Icom R75... I used to have one of those. It's a really nice radio, I wish that I still had it.

If you're only going to be listening, you can set up a really simple center fed fan dipole antenna using a plastic coat hanger and four lengths of wire. You can vary the lengths for the bands you're especially interested in, but it's not as critical as it would be if you were transmitting. If it were me, I'd make two lengths of wire 30 feet long each and two lengths of wire 15 feet long each (again, this is purely arbitrary). On the right side of the coat hanger, attach one of the 30' lengths and one of the 15' lengths to the center lead of some 50 ohm coaxial cable such as RG-8X (use zip ties to attach the cable to the coat hanger). Do the same with the other 30' length and 15' length of wire on the left side of the coat hanger, and attach one end of each to the braid of the coaxial cable. When you hang the antenna, splay the legs of your antenna lengths apart on both sides by about 10 degrees; this is why it is called a "fan dipole". Run the coax cable to your R75's low impedance antenna socket after attaching a PL-259 male connector to the opposite end (from your fan dipole) of your coax cable. Hoist that antenna as high as possible and you're ready to go! You might also want to consider getting an antenna tuner to tweak the antenna's performance.

If you have more room in your yard, you could also try what is called an off-center fed dipole (also called a 'Windom') antenna using a 4:1 voltage balun. For this antenna you only need two lengths of wire, one 45' long and the other 90' long. Attach the 45' length to the connection on one side of the voltage balun, and the 90' length to the other connector on the other side. The voltage balun will already have a female connection on it (called a SO-239) so it's ready to connect a coaxial cable to it. Connect the other end to the low impedance socket on your R75, or better, to an antenna tuner so you can tweak the antenna's performance. Hoist up the antenna as high as possible; you'll be amazed at how much better your reception will be.
 

k9rzz

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EXPERIMENT. Don't limit yourself. Try one of those, take it down, build one of these, take it down, now one of them. Eventually, you'll find what works best for YOU.
 

mbott

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If the budget allows, look at the Wellbrook or Pixel/Inlogics/DX Engineering magnetic loop antennas. I have the RF Pro-1B and I am extremely pleased with it. Being able to rotate it to null out local interference is a major plus for me. Most mornings it allow me to listen to RNZI after their antenna turn at 1100ut. I could rarely get them on my random wire at any time.

--
Mike
 

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wbswetnam

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Looks cool! I have collected most of the necessary components to make a homemade version of the magnetic loop, I just haven't gotten around to assembling it yet.

I'll bet a lot of your neighbors have pointed to it and asked "What the ____ is that??!".
 
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