Post by Sal M. Onella< snip >
Post by John PassaneauI have the Tennadyne 6 el Log periodic antenna. Covers 13 to 30Mhz
with an SWR of under 2:1. It has a 12' boom and the longest element
is 38'. No traps or any other trickery and weighs 37lb. I've had it
up since 2002 and have worked DXCC on all bands and have about 1500
band countries. Which means nothing in reality as it's more of a mark
of my persistence than antenna performance. The fact is the antenna
performs just as the specs say and it stays up even with 1/2" of ice.
I would look carefully at this antenna if you are looking for an all
band high performance antenna.
John Passaneau, W3JXP
Can you get it to work on 40m or lower with a tuner? I ask because I
just have a kluge antenna that I am feeding through a tuner
[TRANSCEIVER > VSWR METER > PI-NETWORK TUNER > COAX > BALUN > OCF
DIPOLE, 8 FT X 20 FT] and it's working better than I expected, even on
40.
Just wondering. TKS.
"Sal"
(KD6VKW)
Hi Sal:
Well you could get it to load with a tuner but it wouldnt act like a
beam.
The directivity of an antenna is controlled by the parasitic elements in
the case of a yagi or by the more complex relationship between elements
in a log periodic. Getting power into the driven element at a lower
frequency than the antenna is designed for doesnt excite the parasitic
elements in the proper manner to make then function and give directivity.
At best it will act like a very short dipole in this case. There are some
who have claimed that this antenna will work on 30 meters, Ive tried it
but it had no directivity and no indication that it worked any better
than my dipole. Others claim it works up to 6 meters. Again Ive tried
that too with no good results.
If I was going to try this antenna on 40 meters, I would short the shield
to the center conductor and feed it as a vertical with a top hat. The
boom of the log periodic is insulated from the tower which makes this
possible. Again though I dont think it will preform better than or as
well as an antenna made for 40 meters.
73
John Passaneau