On Mar 19, 5:59*pm, Wimpie wrote:
On 19 mar, 22:25, JIMMIE wrote:

I was palnning on building a 2M Yagi this weekend and was wondering if
my available bill of materials would have a significant effect on
normal design parameters. The plan is to use 3/4 inch EMT conduit for
the boom and 3/8 inch all-thread for the elements. My concern was that
the threads could change the design frequency.

JImmie

Hello Jimmie,

I think it will be OK, but if you want to be 100% sure, make a dipole
of same thickness tubing and one from the threaded material of choice.
If results are same, you can use it without dimension scaling. *Are
you using galvanized or alu material?

If required, apply some corrosion protection.

With kind regards,

Wim
PA3DJSwww.tetech.nl
.

Galvanized, The pupose was to demostrate that materials can often be
adlib and still have a useable antenna. Maybe this one will not last
30 years before it corrodes away but probably 5 or 6. Also I want to
demonstrate the value of using a jig when building many antennas all
made the same. I have tried the test you mention on 10 meters before
replacing a vertical mounted on my truck. Changing materials didn't
seem to make much difference. WIll try the same for 2M but I dont
have an SWR meter for 2M at this time.. Was hopng someone in the group
might think this interesing enough to try.


Jimmie