Topband: Shunt feed procedure?

[Kenny Silverman]

Hi Tree,  many thanks for the background on the dream beams!  QSL on the effective tower length. ON4UNs book says aunt feeding will work up to 140 degrees. My friend is doing the modeling and it’s hard to imagine we’re more than 120 degrees. We’ll see. Fingers crossed

Regards , Kenny K2KW

> On Dec 10, 2018, at 12:01 PM, Tree <tree at kkn.net> wrote:
> 
> Some anecdotal info on use of Steppir antennas on loaded towers.
> 
> I have never heard of anyone experiencing arcing.  This also includes using other antennas with isolated elements (like KLM).  There just isn't going to be a potential difference.
> 
> I have helped several locals load their towers with Steppirs on them - and nobody has had an issue.  ZL3IX uses an original Monster - as do I - on a loaded tower. 
> 
> When I first did mine - I purposely connected the elements at each end of the boom to the boom electrically.  This was on a 77 foot tower and I found putting the Steppir on 30 meters yielded a good mach with a gamm up about 45 feet.  However, I had one issue that might - or might not - have had anything to do with 160 meter operation.  After a few months - both motors at each end of the boom were frozen.  This was a mechanical issue.  The antenna I put up was used - and had many miles on it - so it is hard to say what was the root cause.  I did have some lightning that could have been a contributor - but how connecting the boom to the element would affect the motors is beyond me.  
> 
> After fixing the motors - I decided to home the elements and use a loading wire off the tower of the tower.  My new installation doesn't need any loading from the elements - since my tower height is now 97 feet and the boom alone is enough top loading.  
> 
> I still feel your tower is too tall - but we have already talked about that.  I do not know if modeling really works for this - but haven't seriously tried it.  
> 
> Tree  N6TR/7
> Manning, OR
> 
>> On Mon, Dec 10, 2018 at 8:47 AM Kenny Silverman <kenny.k2kw at gmail.com> wrote:
>> Hi All,  we’re planning on gamma  loading a 130’ tower with a stack of StepIR  antennas using a cage for the shunt wire. We have modeled the tower. Question: is the model sufficient to determine the gamma wire height?  Or is the procedure to use a single wire to per the model height first to find the 50 ohm point and then build the cage to fit the length?
>> 
>> Also, any tips on shorting the elements on the StepIR dream beam so they won’t arc?  Any anecdotal info on StepIR antennas on the shunted tower?
>> 
>> Regards , Kenny K2KW
>> _________________
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