Can someone point me to a simple S-band helix construction article?
I can find plenty of information on helices and the theory involved with them but a lot of it seems to be contradictory and confusing.. I've found very general guideline type articles but what I haven't found yet is a simple step by step construction article from start to finish. I'd like to construct one using pvc pipe as the helix form if possible as it is readily available but I even find varying opinions on the suitability of that material. Are the dimensions really not that critical as has been stated in some articles? I was thinking of using schedule 40 1 and a quarter or 1 and a half inch diameter white PVC pipe. I could really use some simple formulas as my old brain starts to smoke when I see equations involving algebra and pi. Been way to long since high school! hi hi. Tnx and 73, Michael, W4HIJ
Try:
http://www.wireless.org.au/~jhecker/helix/
John WA4WDL
----- Original Message ----- From: "Michael A. Tondee" mat_62@netcommander.com To: "Amsat-Bb@Amsat. Org" amsat-bb@amsat.org Sent: Tuesday, February 05, 2008 5:11 PM Subject: [amsat-bb] Can someone point me to a simple S-band helixconstruction article?
I can find plenty of information on helices and the theory involved with them but a lot of it seems to be contradictory and confusing.. I've found very general guideline type articles but what I haven't found yet is a simple step by step construction article from start to finish. I'd like to construct one using pvc pipe as the helix form if possible as it is readily available but I even find varying opinions on the suitability of that material. Are the dimensions really not that critical as has been stated in some articles? I was thinking of using schedule 40 1 and a quarter or 1 and a half inch diameter white PVC pipe. I could really use some simple formulas as my old brain starts to smoke when I see equations involving algebra and pi. Been way to long since high school! hi hi. Tnx and 73, Michael, W4HIJ _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Hi John
An interesting article. I noticed that although the writer discusses that the PVC didn't get hot in his microwave oven (inicating it's not lossy), the detuning effect of the PVC dielectric isn't discussed. This was one of the major problems I had when using PVC pipe as a former. If you can take the dielectric effect into account (assuming all PVC pipes have the same dielectric properties), then great. Another common fault is to use a non-central support.
Had I known the above tips, I would have saved myself weeks of fruitless efforts!
Helices are very forgiving antennas in general. The things to pay attention to detail on are the former and the matching section if you're interested in picking up weak signals.
One further thing - the amount of RF at 2.4GHz now that wasn't there seven years ago is astonishing. The pick up from sidelobes of the helix may make performance disappointing for satellite use.
I have a number of articles on building helices including:
http://www.g6lvb.com/60cm.htm#PerfectHelix http://www.g6lvb.com/quadruple_helix.htm
Cheers, Howard G6LVB
Hello Howard and John, Thank you both for the links, a quick glance confirms that they already seem to have more practical information than what I was finding. I'm just trying to do a helix project to see how well I might receive the AO-51 S-band downlink with it. I have several DirectTV dishes here, and an old barbeque grill dish as well but I'm not ready to go that route yet. I'm hoping that 2.4ghz will still be relatively quiet in my area as I live out in a rural community. You never know though, what neighbors I do have could all have wireless LAN's. I hope not. 73, Michael, W4HIJ ----- Original Message ----- From: "Howard Long" howard@howardlong.com To: "'John Franke'" jmfranke@cox.net; "'Michael A. Tondee'" mat_62@netcommander.com; "'Amsat-Bb@Amsat. Org'" amsat-bb@amsat.org Sent: Tuesday, February 05, 2008 6:17 PM Subject: RE: [amsat-bb] Re: Can someone point me to a simple S-bandhelixconstruction article?
Hi John
An interesting article. I noticed that although the writer discusses that the PVC didn't get hot in his microwave oven (inicating it's not lossy), the detuning effect of the PVC dielectric isn't discussed. This was one of the major problems I had when using PVC pipe as a former. If you can take the dielectric effect into account (assuming all PVC pipes have the same dielectric properties), then great. Another common fault is to use a non-central support.
Had I known the above tips, I would have saved myself weeks of fruitless efforts!
Helices are very forgiving antennas in general. The things to pay attention to detail on are the former and the matching section if you're interested in picking up weak signals.
One further thing - the amount of RF at 2.4GHz now that wasn't there seven years ago is astonishing. The pick up from sidelobes of the helix may make performance disappointing for satellite use.
I have a number of articles on building helices including:
http://www.g6lvb.com/60cm.htm#PerfectHelix http://www.g6lvb.com/quadruple_helix.htm
Cheers, Howard G6LVB
Michael, The VHF/UHF manual by the RSGB is well written with charts and practical information. I suggest you look for a copy.
Art , KC6UQH ----- Original Message ----- From: "Michael A. Tondee" mat_62@netcommander.com To: "Amsat-Bb@Amsat. Org" amsat-bb@amsat.org Sent: Tuesday, February 05, 2008 2:11 PM Subject: [amsat-bb] Can someone point me to a simple S-band helixconstruction article?
I can find plenty of information on helices and the theory involved with them but a lot of it seems to be contradictory and confusing.. I've found very general guideline type articles but what I haven't found yet is a simple step by step construction article from start to finish. I'd like to construct one using pvc pipe as the helix form if possible as it is readily available but I even find varying opinions on the suitability of that material. Are the dimensions really not that critical as has been stated in some articles? I was thinking of using schedule 40 1 and a quarter or 1 and a half inch diameter white PVC pipe. I could really use some simple formulas as my old brain starts to smoke when I see equations involving algebra and pi. Been way to long since high school! hi hi. Tnx and 73, Michael, W4HIJ _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
participants (4)
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Howard Long -
John Franke -
kc6uqh -
Michael A. Tondee