My new Cushcraft 2meter/70cm antenna is a very poor performer; so poor
that something must be wrong. The only thing that doesn't check out are the
"Reddi Match" elements. Should the outside tube of the "Reddi Match"
elements have continuity with the center conductor of the coax, and thus the
beam, and thus ground, like a folded dipole? Neather of mine do. There is
no "physical" connection between the coax center conductor and the driven
elements of the antenna.
All I can think of is that there are insulated elements inside the
"Reddi Match" tubes which radiate to and from the driven elements. After
checking everything, this is all that I can find odd.
Does anyone have experience with this model of Cushcraft, or a similar
design, who can tell me if this is normal? Thank you in advance.

Tom

Looking at the instruction sheet on the Cushcraft website (since I
wasn't familiar with this antenna), there is indeed no direct connection
from the coax center conductor to the driven elements. This is a gamma
matching network. The center coax conductor is connected to the inner
tube of the "reddi-match" piece. It has a plastic insulator around it
and slips inside the outer tube. This forms a capacitor. The RF "jumps
the gap" from inner to outer conductor and then travels to the driven
element via the small shorting strap connected between the reddi-match
outer conductor and the driven element.

The places I would start looking for trouble is to measure the distances
on the reddi-matches to match the instruction manual. Have you checked
SWR with a meter? You also might check for continuity (and lack of
short circuits) between inner and outer conductors of the coax
"combiner" that attaches to each of the reddi-matches and allows a
single feedline up to the antenna.

You were careful not to get any of that silicone grease (insulator!)
into the center pin of the coax connector that is attached to each
reddi-match assembly, right?

This is the same type of setup on my A147 2M yagi from Cushcraft and
mine works fine.

Scott
N0EDV



Tom Tretheway wrote:
My new Cushcraft 2meter/70cm antenna is a very poor performer; so poor
that something must be wrong. The only thing that doesn't check out are the
"Reddi Match" elements. Should the outside tube of the "Reddi Match"
elements have continuity with the center conductor of the coax, and thus the
beam, and thus ground, like a folded dipole? Neather of mine do. There is
no "physical" connection between the coax center conductor and the driven
elements of the antenna.
All I can think of is that there are insulated elements inside the
"Reddi Match" tubes which radiate to and from the driven elements. After
checking everything, this is all that I can find odd.
Does anyone have experience with this model of Cushcraft, or a similar
design, who can tell me if this is normal? Thank you in advance.

Tom