[TowerTalk] DIR-DE-DIR on a 40m yagi ?

[Gedas]

A couple years ago when I was into 6m MS I was using an old CC 5-elem 
yagi at 75'. It worked very well and I was able to make hundreds of 
QSO's out past 1000 miles pretty much at will.

Along came some straight line winds which ripped off 1/2 of the 
reflector. On 6m it meant the reflector was gone. Surprisingly the SWR 
was not horrible so I just kept using it.

Soon I noticed that I was getting awesome reports off the front and rear 
of the antenna. This actually was a blessing since I did not have to 
turn the rotor and could cover huge parts of the country with one 
setting. The reports off the back were just as good as off the front 
when I turned the antenna and made repeated contacts with the same stations.

When I modeled the antenna sure enough the crippled antenna showed a 
beautiful, almost perfect bi-directional pattern. The front lobe was a 
dB or so stronger than the rear but I loved running the antenna that 
way. It was many years before I fixed it (actually I kinda miss it). 73

Gedas, W8BYA EN70JT

Gallery at http://w8bya.com
Light travels faster than sound....
This is why some people appear bright until you hear them speak.

On 11/14/2021 8:36 PM, David Gilbert wrote:
>
>
> If you want to make a 3 or 2 element array be bidirectional, tune the 
> parasitic elements to the driven frequency.  Don't make it shorter or 
> longer.  You can run that through EZNEC if you don't believe me.
>
> 73,
> Dave   AB7E
>
>
>
> On 11/14/2021 3:16 PM, jim.thom jim.thom at telus.net wrote:
>> You folks   that have stepIR   3 el yagis..... I believe you can reverse
>> the pattern
>> 180 degs.... by turning the DIR into a REF...and vice-versa.
>>
>> Question is,  can you make  BOTH parasitic elements into Directors ?
>> IE:    DIR-DE-DIR.  On paper, it should become a  2 -element,
>> bi-directional  yagi...with perhaps  4dbd  gain in both directions 
>> .   Does
>> that concept work ?
>>
>> I'm  assuming equal spaced elements to begin with..and  DE mounted to 
>> the
>> mast...above the boom a bit.
>>
>> Aside from the 180 deg reversal  feature,  for  SOME applications,  
>> having
>> gain in 2 x directions at once can be of benefit.
>>
>> Ok, here's a  dumb question.  What if both parasitic els are tuned as
>> Reflectors ?   Does it implode on itself,  or is it  still bi-diectional
>> with gain ?
>>
>> Jim  VE7RF
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