[Lowfer] Antenna design idea question

[Michael Lodico]

Hi Ed,

Thanks for the info.  I have that handbook and will do some research.  
If Randy used 2" PVC for the 50' I can see why you guys had all that 
trouble raising it.  That is why I was looking at 4", 3", 2" and 1 1/2" 
schedule 80 PVC like I used in my water well business.  It is heavier 
and less flexible than normal schedule 40. One thing that I will have to 
look at is the inductance of each 10' section as they will be 
different.  Part of what gave me this idea wasn't just the 80 meter 
article but I had mobile antenna years ago, don't remember who made it, 
that was wound somewhat like this.  The bottom was fatter than the top 
and the windings were spaced father apart at the bottom and got closer 
together at the top giving it a top loaded design which I found 
transmitted extremely well and wasn't as fussy about ground.  You have 
given me some food for thought, thank you.

73,
Mike
K1EG

Ed Phillips wrote:
>     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
>> ______
>>
>>     
>
>
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