I think you need to model what you are attempting. You don't mention
the antenna support and if it is a tower then there is a fair amount of
interaction with the V. However, a 39' boom will help if the tower is
at the midpoint. I've modeled a number of phased 80m delta loops on a
89' tower and you might consider delta loops vs an inv. V. With a 120'
support and a 39' boom you've got a good start for a great antenna.
For it to perform as a parasitic beam on two frequencies, then the
inductance needs to be added to both elements. Using a tuner to get
acceptable swr doesn't change the pattern, which may even reverse from
what you want. Cut for SSB and add feedpoint inductance for CW and
perhaps have two values of L to cover most of 3500 to 3840 or so. PVC
junction boxes on the boom ends with relays for switching. This is how
my 2L JKantenna beam covers 3500 to 3840.
Another (and probably better) choice is to drive the two V or loop
elements out of phase to create the pattern. You may find a design that
has enough swr bandwidth for SSB and CW. Optimize the (switched)
phasing lengths for pattern since swr coax losses are low on 80m and
your tuner can make the amp happy. A quick mod of my phased loop model
says this may work.
check out
http://www.transduction.com/PDV.pdf
and W8WWV's work on 80m V
http://www.seed-solutions.com/gregordy/Amateur%20Radio/Experimentation/IVee80.htm
there is also a lengthy blog like tale of phasing two V's on a tower
(gave up after 3 years) but I can't find it now, perhaps other TT'ers
have the link.
Grant KZ1W
On 3/31/2017 5:00 AM, Martin Pelt wrote:
I am putting a 80 meter 2 element inverted vee beam up. It will be at 120
feet with 39 foot boom.
I have 2 questions dealing with switching from phone to cw without lowering
elements and using jumpers.
I plan to use ladder line on driven element coming down to tuner to switch
from cw/ssb. Will this work or is there a better way ?
On the reflector I thought maybe cutting it for ssb the having inductor
with relay at the center to switch to CW. Is this the best way ? If so how
can I easily measure resonate frequency with inductor inserted at the
center ?
73 Martin N4UU
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