[TowerTalk] 80 Meter beam

[Kelly Taylor]

Here’s a thought: if one can use a fan dipole to make an inverted vee cover both 80 and 75, how about a fan reflector?

73, kelly, ve4xt 


> On Mar 31, 2017, at 9:30 AM, Grant Saviers <grants2 at pacbell.net> wrote:
> 
> 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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