[TowerTalk] 6 mtr quad

[Martin Sole]

I've long been a quad aficionado and have generally devoured any 
information I can find on them. The double driven W6PU quad is an 
example of something a little different that suggests it can still be a 
useful antenna. I still have a lightning bolt quad along with lots of 
extra parts and hope to shortly rework it as a 3 element with 30 and 40 
added to the other 5 bands together with moving the10 and 12m elements 
to improve on their compromise positions. We'll see.

But in all of this the information by Cebik probably stands out as the 
most thorough examination of the quad and it's comparison with the yagi 
array. My take away from his work is whilst the quad might well 
demonstrate some gain advantages in some situations it suffers from 2 
seemingly intractable issues. Firstly the gain, F:B and SWR responses 
are somewhat more "peaky" than the equivalent yagi curves. Secondly that 
these responses are less well aligned. That great 30dB F:B at the CW end 
of the band matches to an unfortunate 6 dB drop in peak gain whilst up 
in the SSB end of the band the extra bit of gain is matched to a meagre F:B.

I do think that the closed loop antenna tends to be lower noise, there 
seems to be a lot of anecdotal information that makes this hard to 
ignore and my own experience points to much the same. In SE Asia we do 
get lots of heavy monsoon rain and there seems little doubt the quad 
works better at those times.

I definitely would agree that like the newer dynamic antennas the quad 
really needs either a telescopic tower or one with a fast and convenient 
raising fixture. The frailty of both these antenna types on a fixed 80 
foot plus tower is never going to be ideal.

Martin, HS0ZED



On 31/08/2016 20:44, Joe Giacobello, K2XX via TowerTalk wrote:
> Ed, I have been using quads since the late 70s.  My first one was a 
> Skylane tri-bander, which used low strength, flimsy spreaders compared 
> to what's available today.  I've also had a couple of six band quads 
> with four elements on 10-20M and seven on 6M with a 24 foot boom.  
> They do indeed work well and, when multibanded, are far less of a 
> compromise than multiband Yagis.  A 2 element quad has only about 0.3 
> dB less gain than a three element monoband Yagi.  Going to 
> multielement quads beyond three elements is an exercise in rapidly 
> diminishing returns.  The gain increase is relatively small given the 
> increase in expense, complexity and vulnerability.  Four element Yagis 
> and beyond are then a better investment.
>
> I am currently using a two element duobander on 30 and 40M on a 20 
> foot boom.  It's almost equivalent to a three element monoband Yagi 
> but on a far shorter boom.  Cubex's 26 foot spreaders have held up 
> well at this windy QTH, although the combination of ice and wind can 
> be destructive.
>
> 73, Joe
> K2XX
>
>> Ed Sawyer <mailto:sawyered at earthlink.net>
>> Wednesday, August 31, 2016 9:16 AM
>> The Quad vs Yagi debate is timeless. I always thought there were a 
>> number
>> of things contributing to it:
>>
>> - Back in the day before computer optimized gain yagis, the quad
>> was a simpler way to get more gain on a given boom. The full loop 
>> started
>> it off with something like 1.3dB gain over the dipole element and 
>> placing
>> evenly spaced elements gave good results for a 2 or 3 el quad.
>>
>> - The average height of a quad (I have to believe) is the center
>> point between the top wire and the bottom wire (or diamond tips) so 
>> the HFTA
>> analysis should be the same for a yagi vs a quad at a given height when
>> horizontal polarization is used.
>>
>> - However for the early years, low "towers" of 30 ft or so, if they
>> were fed for vertical polarization and happen to be in a good to 
>> excellent
>> ground conductivity area, the take off angle was likely better for long
>> "band opening" DX and impressed their owners.
>>
>>
>>
>> Today, there is much better ability to get maximum gain out of a 
>> longer boom
>> yagi that is way easier to install and maintain and we understand the 
>> take
>> off angles much better.
>>
>>
>>
>> I could be wrong on the above folklore, but that's my guess.
>>
>>
>>
>> Ed N1UR
>>
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