No one? =(
The trick of this antenna comes down to matching it properly or you end up with some nasty sidelobes that kills your forward gain. Try adding or removing just 1/4 turn and you should see some changes. Remember that the helical begins to become a transmission line near the feedpoint and thus, the shorter this matching section is, the better results you will have.
I measure gain just for an indication.
It's not reliable I think.
I put a vtx with attenuator a few meters away from my desk and use the IRC power meter on dB settings to find the peak values.
Works fine with directional antennas but not that good on omnidirectional. Get a lot of up and downs there.
Don't have a clear 0 value as antenna so just comparing between identical or different antenna's.
What do you mean by matching.
Only vSWR or something else. Swr is most of the time only by tuning the feed point.
Good to know it has to be a short as possible.
In my case most of the time you should start as low as possible at feedpoint to get it almost right.
Bandwidth you're right.
That's why I use thin wire. It has a great bandwidth so with thin wire it gets a bit smaller. Still big enough for most Vtx channels.
I love these still. My favorite antennas for 1.2ghz (1010-1.3). Compact enough that I run a pair in my backpack 60* offset in diversity with some LNA's and the coverage is just un-freakin believable.
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Last edited by Toysrme; 26th December 2016 at 03:23 PM.