[TowerTalk] add a 3rd el to 40-2cd

[Grant Saviers]

You're probably right about coil losses.  Re putting up the Moxon. It 
took careful threading of all the aluminum around the mast even with a 
boom lift, which is how I got mine on a HDX589 lowered.  The identical 
40m Moxon I built with K6KR went on his tower mast with a crane.  The on 
the ground footprint is 36' x 48'.

My 10m beams are on different towers.  Since the Moxon tips are near 10m 
resonance it could be a problem for a stacked 10m  but the tips are 
perpendicular to yagis aimed the same.  I don't recall a feedpoint 10m 
resonance but would have to check to be sure.  Maybe in 5 years if there 
a 10m band then :(

btw the boom on the scratch built ("120mph") version is 26.7' vs the 22' 
of the Cushcraft conversions.

Grant KZ1W



On 3/6/2018 17:55 PM, john at kk9a.com wrote:
> If your 3el 40m F.S. sounds like a fantastic beam however if it had tiny
> Cushcraft loading coils you probably would not refer to it as a flame
> thrower:)
>
> The Moxon is a great design and it eliminates the low-Q CC coils. I am not
> sure what issues there are installing Moxon elements on a tower or mast. If
> I recall correctly it is also resonant on 10m which may cause some
> interaction issues.
>
> John KK9A
>
> -----Original Message-----
> From: Grant Saviers [mailto:grants2 at pacbell.net]
> Sent: Tuesday, March 06, 2018 7:36 PM
> To: john at kk9a.com; towertalk at contesting.com
> Subject: Re: [TowerTalk] add a 3rd el to 40-2cd
>
> Kostas,
>
> As others have said, it is all about boom length with 3 elements.  I built a
> W6NL Moxon (scratch design) and have a custom 3L full size 40m on a 48'
> boom.  Moxon is at 92', 3L at 140'.  Needless to say, the 3L is a mighty
> "flamethrower" vs the Moxon, hardly a sensible comparison, height, boom
> length, extra element.  F/B and F/S with the 3L is quite a bit better,
> listening A/B.  My Moxon is a very good antenna, the full size 3 element is
> a great antenna.  In some contests the Moxon covers the USA and the 3L is
> pointed at the DX opening.
>
>   From what you have, building the strengthened K3LR version of the W6NL
> Cushcraft/Moxon  is a straightforward and proven way to get a very good
> antenna.
>
> Grant KZ1W
>
> On 3/6/2018 13:57 PM, john at kk9a.com wrote:
>> I have OptiBeam 40m antennas and when playing with a model, adding an
>> element really did very little. I do not recall the details but I
>> think some things like SWR bandwidth were even worse. You are probably
>> better off using the aluminum to make a Moxon
>>
>> John KK9A
>>
>>
>>
>> From:	kostas sv1dpi
>>
>> In my club we have a Cushcraft 40-2cd antenna. We are very satisfied
>> with this antenna. Recently, one of our members, donated us a second
>> 40-2cd. We have not a tall tower to put them in phase (the antenna now
>> is at 22m-72ft). We made a thought to shrink a little the reflector of
>> the 2nd antenna and use it as director in a 3el configuration. Do you
>> think that it will work? Can anyone to make a model and tell me what
>> is the new length of the boom and in what position we need to put the
>> elements to have 50 Ohms and finally which is the gain?
>>
>> On behalf of SZ1A
>>
>> 73 Kostas SV1DPI
>>
>> _______________________________________________
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>>
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