On 9/11/06, Peter Dougherty <w2irt@comcast.net> wrote:
>
> Hi again.
>
> Thanks to all who've replied off-list re my grounding questions.
>
> Now, I have another situation that's providing me with more questions
> than answers. I need to correct a bad miscalculation that I made when
> planning my antenna system, and frankly money is now getting somewhat
> tight.
>
> What's up now is an LM-470 tower with 10' of Aluminum mast. At about
> 2' above the thrust bearing is a C31XR, then at the top is a WARC
> Yagi, (2-2-1 from Force 12, 7' boom). I figured that will give me
> everything I need for 10-30, and so far it's lived up to expectations.
>
> However, I badly miscalculated on how critical a band 40 is. I have
> an Evans 40-80-160 wire configured as an Inverted Vee, apex at the
> 65' mark off the tower. It plays OK on 80 but it's a black hole on
> 40. With 1500W, I typically need 20 or 30 calls to get anything in
> eastern Europe, Russia, etc. Only way to work VK/ZL is to be there
> when nobody else is. I can't break any pile on 40, and I'm getting
> slaughtered every year in CQWW once the sun goes down, and until 80
> opens up. Not just that, but I kill everything in the house with RFI
> (even with ferrites!) on 40 - I'm clean everywhere else.
>
> I need to get something done before CQWW, but frankly I don't know
> which way I should go. I was thinking a BigIR vertical, but I suspect
> QRN will be a problem. Wires just don't cut it from here, as the last
> year has proven conclusively. This is a 1/4 acre suburban lot, and
> the variance I have only allows one tower.
>
> I have a budget of no more than $1500 including installation for
> this. Do I have any hope of a solution?
>
>
>
> Cheers,
>
> Peter,
> W2IRT
Hi Peter,
I suspect that you would find that 1/4 Slopers phased correctly off the
tower would work quite well and give you some directivity to boot. I used
that very system back in the 70's for CQ WW TEST with good results-- believe
I used four slopers about 45 degrees apart around the tower with the feed
line length calculated to make the unused elements act as reflectors.. not
as good as a beam but much better than a dipole at the same average height.
73's and good luck
Dave kc1di
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