That antenna is a GREAT start to a SUPER antenna. I did some extensive
modeling on the 34 foot boom length for the yagi I built for my QTH from
a old 617-6B. The full results are published in the proceedings of the
24th eastern VHF conference available thru the ARRL. Here it is in a
nutshell... all from K6STI's YO
Spec 617-6B stock N1DPM 7 Element
(you'll need another director)
Gain (free space) 11.83dBi 12.85dBi
F/B ratio 22.5dB 29dB
1st E plane Sidelobe (horiz) -19dB -25dB
1st H plane Sidelobe (vert) -10dB -18dB
Note the 1dB extra gain and the biggest "real" difference is the 1st H
plane (vertical) sidelobe. This will "cut" local noise down on receive
and the RF level on transmit that is wasted pointing up in the air at ~70
degrees and down at the ground at ~70 degrees. Not only has this greatly
improved my hearing on 6 meters it also went a long way in allowing TVI
and RFI free operation with 1.5 kW output not to mention that the RF
exposure regulation stuff was met no problem. In the article I also
provide plots of other antennas of the same size for comparison.
Here's the dims....
spacing element end length
REFLECTOR 34.25"
54.695"
DRIVEN ELEMENT 32.50"
40.542"
D 1 30.75"
62.295"
D 2 29.125"
69.247"
D 3 28.125"
82.042"
D 4 27.187"
89.304"
D 5 25.25"
These dimensions are in decimal format right off of YO but mine was built
with a Craftsman tape measure! After all it's just 6 meters.
The shorting bars on the match should be placed 12.25" out from the inner
ends of the T match bars to the inside surface of the shorting strap.
This resulted in a 1.025:1 VSWR at 50.150MHz.
That should give you enough to build one of these! Again the artical
describes a lot more detail.
73 C U on 6!
Fred
N1DPM
FN32qb
On Fri, 19 Mar 1999 10:15:32 -0500 Bert - NS4W <ns4w@tdsnet.com> writes:
>Hi all,
>
>Goofed, serves me right for trying to remember the model #.
>
>I am looking for dims on the 617B.
>
>
>Bert
>
>
>
>Joe Reisert wrote:
>>
>> Hi Bert,
>>
>> I don't know the antenna model. Are you sure of the model number?
>They have
>> a 617B and a A50-6.
>>
>> If you find any info, please let me know as it's new on me. Any mods
>also
>> appreciated as I developed the A50-6S for them.
>>
>> 73,
>>
>> Joe, W1JR
>>
>> >Does anyone have a set of optimized dimensions for a
>> >CushCraft 614-B six element six meter Yagi ?
>> >
>> >Problems: owner-towertalk@contesting.com
>> >Search: http://www.contesting.com/km9p/search.htm
>> >
>
>------
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