[amsat-bb] Re: 1.2ghz helix
lucleblanc6 at videotron.ca
Wed Oct 29 01:02:09 PDT 2008
On 29 Oct 2008 at 2:58, w7lrd at comcast.net wrote:
> I am almost finished with a 16 turn helix for 1.2ghz. I am not sure of what type of matching I should use.
> Some of designs I have seen use a flat tab on the first 90 degrees of the helix. What size should it be? Is there a better way? I > have a bird 43 with a 1.2 slug for tuning.
> 73 Bob W7LRD
Here is a clever way to match an helix http://helix.remco.tk/ For 1.268Ghz a 3" tube od with caps seems to fit near the formulas
dimension. The problem is the stub foil dimension on 1.268Ghz could be a pro rata of the S band will be good enough?
Experts idea are welcome with figures for a L band model
Luc Leblanc VE2DWE
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