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Re: Helical array (was ... well never mind)




On 1999-05-21 kf4fdj@AMSAT.Org said:
   >CC: amsat-bb@AMSAT.Org

   >Whatever the case, I highly recommend a mast mounted preamplifier
   >for 70 cm, helix -OR- Yagi.  Not only can I hear very weak signals
   >with my KLMs using an ARR preamp, but the extra "section" before
   >the receiver front end improves the out of band rejection on my
   >FT-847.

 Actually was thinking of building one for 70 cm and 2 meters, I am
 interested as I have a readily available supply of 1/8 and 1/4 inch
 hard drawn copper line stock available. Also I agree that the setup
 appears to be rather awkward. Have you ever experimented with the mast
 mount T.V. Antenna Pre-Amps? I am looking at one here now and it has
 a noise factor of about 3 db, not too bad but I am going to play with
 it to see if its feasable to improve the s/n ratio by narrowing the
 bandwidth a bit. Seems to me with all the garage sales going on here
 these days you can get some great junk to convert for sat use. How
 about feeding that Helical antenna with 75 ohm T.V. Coaxial cable?
 Looks like it could handle maybe 25-50 watts? Trying to get a cheap
 station setup for the local School who are interested in Sats and
 Amateur Radio. Found a couple of Alliance U-101 TV rotator's last
 Fall so may try to come up with a cheap interface circuit so it
 can be computer controlled. My wife says I tend to be "Stingy", if
 she means "thrifty" and "forward thinking" I would have to agree with
 her! But I suspect she ment I am just too cheap to BUY the REAL stuff.

73
Terry

terryb@bmts.com

Net-Tamer V 1.11.2 - Test Drive

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