[Lowfer] Antenna design idea question

[Ed Phillips]

    I am aware to two such efforts to put a helical antenna on 1750 
meters here in Socal.  Neither was very successful [performance 
noticeably poorer than simple base-loaded 40 foot "push-up tower] and 
I'm afraid you may go to a lot of work and be disappointed with the 
results.  Randy Sedan, WD6ELU, went to a lot of trouble to make a 50 
foot helical using 2" PV; it was white but I don't know the schedule.   
I forget the wire size or turns but he wound it full from end to end and 
I was part of the crew which assembled to help him raise it.  Turned out 
to be a giant fiasco.  We had ropes attached in many places and guys on 
ladders and on his roof to help get it up.  Turned out that the PVC was 
more like limp spaghetti and we succeeded in getting both the top and 
bottom perpendicular to the ground with the middle bent into a perfect 
U.  From this point things went slowly because everyone concerned was 
paralyzed with laughter and we all [some of us were OLD men] kept 
getting the giggles.  Eventually it was maneuvered into place and guyed 
so as to be straight.  It worked, sort of.  He had it base loaded and 
was able to put out a signal from his beacon ELU but it was at least a 
couple of S units weaker than the original mast and was almost inaudible 
at my location, which is about 50 miles away.  I could copy the CW OK 
but his SSB voice announcement was unreadable.  Bottom line was that it 
was a lot of work for him and a great disappointment

    While he had much less than a quarter wave of wire on the thing I 
suspect the results would be no better with more wire.  The ITT 
handbooks 'REFERENCE DATA FOR RADIO ENGINEERS' have lots of info on the 
design of such helicals and perhaps a better design would have worked 
but I doubt it.

Ed
W6IZJ
IZJ [sometimes]

Michael Lodico wrote:

>Good morning all you Lowfer's out there.
>
>I am trying to plan for an antenna for this winter and came up with an 
>idea based upon what a ham did for a shortened 80 meter vertical.  The 
>plan is as follows:  you take a 1/2 wavelength of wire and wind it on a 
>rod like a solenoid so that it is shortened considerably.  He claims 
>that it performs quite well.
>
>What I have in mind is to take 4 lengths of PVC heavy wall pipe, 4", 3", 
>2" and 1 1/2", and wind a 1/2 wavelength of wire over the 40' length.  I 
>would do this in 10' lengths and dope the windings in place to hold them 
>and then connect them together at each joint.  At the top I would add a 
>10' diameter capacitor hat.  By using the different diameters this gives 
>me  anchor points for  Dacron guys.
>
>My question is has anybody tried this?  Is it a feasible design idea 
>worth pursuing?  Any comments or feedback would be greatly appreciated.
>
>73,
>Mike
>K1EG
>______
>