[TowerTalk] DRIVEN VERSUS PARASITIC 160 antenna

[Dennis OConnor]

Well, remotely adjustable elements would allow the optimizing of gain and f/b across the band for a parasitic array....  It is certainly doable even on 160, but is it necessary?  
On 160 I rarely go above 040, or so... QSY over 40kc is not that hard to have both gain and f/b stay good (not perfect, of course)...  In the rare circumstance that I might want to go higher I know that the gain and f/b are compromised... 
When I want to go higher up in the band AND keep the gain and f/b, I walk out to the arrays and remove one or more of the clipped on tips which retune the array elements in 50kc steps...  Not very elegant, but really cheap and effective... 
I have actually cobbled up on the bench, an air powered knife switch to to remotely control the element length... It works just fine, is not sensitive to the high voltage RF fields at the ends of the elements, and is not too expensive (relative term)... At this point in time I have no great urge to go that that expense and work just for convenience... For a flagship M-M contest station, the expense is justifiable...

Certainly, the driven 4 square arrays can be retuned with relays and networks...  

denny - k8do





			
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