Quadrifilar Helicoidal

[VK4ZEJ]

Hi All,

Just wondering if anyone has had any success with this type of antenna for satellite work. If so, would I have to build 2 seperate antennas for 2m and 70cm or can I combine and build the 70cm one inside or on top of the 2m one.

Eddie - VK2ZEJ

[VK2GOM]

Hi Eddie,

Build them separate.

They work BRILLIANTLY. I built one for 137MHz, and with a MiniKits preamp tuned to 137MHz I was receiving weather sats S9 from 1deg on the horizon. Their only drawback is if you have a satellite go over your absolute zenith (directly 90deg up) there is a 'hole' / null there, but it's not much of an issue since a) it's rare for a satellite to pass through that area, and b) it's quick!

There are online design programs for them. I punched in the numbers, got the printout and built it from PVC tubing and RG58C/U. I built another one with a wooden spar frame but it never worked as well as my PVC one.

Work carefully and think about it, since it can be tricky getting the iron inside to the tube to solder it up, for instance.

If you look in the forum here, you should find pics of my antenna. Search for QFH to find it. SEE HERE: viewtopic.php?f=46&t=8668

73 - Rob VK2GOM / G0MOH

[VK4ZEJ]

Thanks Rob,

Have been looking at the online calculator and have the RG58 and PVC. Now just to build them and see what happens. Hopefully catch you some time on air with them.

Eddie - VK2ZEJ

[VK4CRO]

I built one for 70cm many years ago when the initial article came out in QST
worked Brilliantly !!!
de cro