[amsat-bb] Re: HELIX REFLECTOR?

According to the W1GHZ antenna book at : http://www.w1ghz.org/antbook/conf/Helical_feed_antennas.pdf "The ground plane diameter is typically 0.94? in diameter" or about 25.25" for 440 MHz. John WA4WDL -- From: "Pete Norris, K1HZU" Sent: Thursda

[amsat-bb] Re: HELIX REFLECTOR?

Hi Pete, Take a look at this article on helix ground planes: http://www.alzacomm.com/downloads/Helix_Letter.pdf It is also possible to make a helix with no ground plane. This was a cover article of the IEEE Antennas magazine in 1995. Search f

[amsat-bb] Re: HELIX REFLECTOR?

At 04:51 PM 6/3/2010, Pete Norris, K1HZU wrote: >Hi All: >I am rebuilding a 440 MHZ Helix that I built several years ago . It >worked very well, but I would like to reduce the size of the >reflector to a more manageable size than I had before. The only >reference to reflector size I can find is,

[amsat-bb] Re: Helix Reflector

 Ed - KL7UW, WD2XSH/45 said:   "You might be interested in the Helical Beam that Mike Cook designed in 1996 for reception of the Mars Global Surveyor (MGS).  He used a 10.66 inch diameter loop Reflector. "    I have built two 70 cm helix antennas using the loop reflector. The first one was an

[amsat-bb] Re HELIX REFLECTOR?

To add to the discussion the July/Aug 2007 Amsat Journal has an article covering some gain comparisonmeasurements I made between four 13 turn (2.88 wavelengths) 13cm antennas with different square solid aluminum reflectors. The sizes were 0.56 wavelengths, 0.84 wavelengths, 1.0 wavelength and 1.

[amsat-bb] Re: HELIX REFLECTOR?

- Original Message - From: "Pete Norris, K1HZU" To: Sent: Friday, June 04, 2010 2:51 AM Subject: [amsat-bb] HELIX REFLECTOR? > Hi All: > I am rebuilding a 440 MHZ Helix that I built several years ago . It worked very well, but I would like to reduce the size of the reflector to a more ma

[amsat-bb] Re HELIX REFLECTOR?

Hi John, I agree with you. I have in my hands the book "RADIO ASTRONOMY" by John Kraus ISBN 07-035392-1 This is the text of page-200 "An example of a partially steerable (meridian transit) array antenna is presented in Fig.6-41 This antenna,built in 1952 at the Ohio State University radio obse