I was wrong Bob, the tip is NOT adjustable. Looking at the antenna image in the manual, it shows a screw is securing the tip element also. So, it looks like the whole antenna is fixed, and your right the frequency is adjustable via the gamma dog bone first at 43" from the top on the base element, then some fine tune adjustment can be made with the gamma stinger, but a caution says, "...do not reverse this process."
Boy, I understand now why guys have trouble with this antenna. They are using a pig tail stub connection, and that makes checking the SWR at the feed point impossible without a jumper or feed line, both of which can cause transformation if the load is not already near perfect at the desired frequency of operations. This says nothing about raising the antenna and seeing the match change due to height. This one might take a highwire act to tune.
You are right Bob, the JGSOG is intended to tune within the range given, 26.000 - 29.500 mhz, using the gamma adjustments only. So, in order to determine the length for this antenna for modeling purposes, one would have to get the specific length from JG and how it was measured. Or use a perfectly stock antenna from JG, assembled and measured between two specific points. We know for sure one point is the tip.
You're right again, we need to know the antenna is unmodified, and where the bottom is measured from, just like you state.
So, this may mean the old 3/4 wave idea is still valid, right?
I didn't think so either.
I agree, but if you're right and this antenna is that much longer than a 5/8 wave of about 22.5' feet, then what about the 3/4 wave rule? My model doesn't seem to suggest that this particular radial design fixes the 3/4 issue like happens with the Sigma4. Maybe I'll have to fix the radials on my JG to fully horizontal, and see what the difference is.
My buddies SOG was mounted on a 25' foot tower and went through hurricane Ike, when it came thru the Houston area in 2008. It was bent a little, but still working. I took all of my stuff down.
