That is not a problem... I could be of help.
What I need from you:
1- The boomlenght.
2- element diameters and section lengths.
(for example does the element contain 3 sections ...the centerpart 2 meter long 25mm diameter and the tips are 20mm in diameter to complete the element lenght.
3-confirmation the element distances can be moved
(some yagi's have the elementy bolted on fixed spaces).
4- Your preferred design frequency. ...say 27.025 or 27.555 MHz (for example).
5- a bit of time
I understand you are going to consruct a gamma-match.
THat will work oke, no worries.
Though personally im not to enthusiastic about gamma-matches...or any matching type at all.
Normally i prefer "direct fed" 50 Ohms,
For a couple of reasons:
1- No mather how litlle it may be, a matching system will introduce some loss..i like to prevent that.
2- A matching system normally limits the power handling capabilities of the antenna.
3- If something is wrong with the antenna (especially after years of service) it 9 out of 10 times is ...the matching system.
4- If a yagi is direct fed, that leaves no room for error. If your SWR isnt what it supposed to be ...you know there is an error, you will never know that with a matching system as you just "tune" the error's away.
But it is easy to use for verious impedances.
ll design the beam a bit lower in impedance so you can match it with the gamma-match.
You can get an idea of what is possible from here:
cb-antennas.com
Kind regards,
Henry
19DX348