In a message to Wayne Sarosi  Rob Dennis wrote:
 WS> That is something I was going to do here except it would be for 50MHz
 WS> to 800 MHz. I want to constuct it so it sits on an AZ-EL rotor.
 RD> Wayne how long is this going to work out to in boom-length ?
It was around 16 feet. I still working on an inexpensive way of
turning in from vert to horz. I have designed a method but
need to test it out.
 RD> I'm trying to keep the boom no longer
 RD> than 16 feet as I have a tree next-door
Lets' see. My antennas hang over my neighbors house but they don't care.
They have Bamboo under my antennas and I have to keep it trimmed for them. 
I have a 50 foot sycamore which is encroaching the top of my HF LPDA.
 RD> What if I keep the BW narrow for the SSB/CW portions of each
 RD> band only and work my calculations to optimize the antenna for
 RD> that specific area only ?
It doesn't work that way. The antenna is Log Periodic. What you
are trying to do is optimize at specific frequencies which are not
log periodic from your starting frequency.
 
 RD> A little window of 800Khz or so in each
 RD> SSB/CW portion should be enough for
 RD> most CW or SSB work on 6m,2m or 70cm.
 RD> I only want this for SSB/CW as I plan on a pair of co-phased Cushcraft
 RD> dual-band beams (5 elements on each band) for use on 2m and 70cm FM.
 RD> 6m FM is covered by the Ringo vertical for now so is not a problem.
You can do that but not with the LPA. What you want is basically is one
antenna with multiband capabilities. Hmmm. That one might prove
interesting to design and build. 
 
 RD> And if the window is only a 800KHz wide
 RD> area the phasing stub should be able
 RD> to cover just the SSB/CW portions only or
 RD> am I getting into more of a problem
 RD> with calulations for BW and phasing ?
It'll be ... button pushing on the calcualtor.
 > WS> 20m is basically flat, 17m is basically flat, 15m is surprizingly
 > WS> flat since my roof flashing can run 40m without a tuner, 12m is
 > WS> OK, 10m is just fine. All this with no tuner! So 17MHz and the low
 > WS> end of CB are not that good but who cares.
 RD>  Well you can always use the tuner for
 RD> 17m so the rest are gravy with no
 RD> tuner needed at all.
No, 17MHz not 17m.
 RD> I've been thinking of getting a few
 RD> sections of scaffolding for working on my
 RD> antennas as they are only up at 30-35 feet (soon to be 40 feet).
 RD> Being near to the airport (less than 3
 RD> miles away) I have to stay below 50
 RD> feet or add a set of beacon lights and get permission to erect
 RD> anything higher than 50 feet and all sorts of other paperwork from IOC.
 RD> Compromise at 40 feet is that it is easier to work on and a
 RD> large apartment block north of me acts as
 RD> a partial block to intermod on 2m.
Sound neat. I'm near an airport too but the 80 foot white pines save 
me from the FCC requirements. I'm only at 45 feet.
-WS
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