[Elecraft] Off-Topic - Antenna element repairs

[Rick Bates, NK7I]

If you can find a length of tubing one size larger (so that the pieces 
to be repaired just barely fit inside); cut a length long enough to 
provide lateral strength (side load), cut slits into the ends of the 
patch lengthwise then overlay that to 'mend' the two pieces (make it 
continuous again) and use worm gear clamps on the slits to bind it 
together (making sure that the original two parts are close so you don't 
have to trim to resonance).

The overlaid section will be stronger than the original (two layers) if 
you do this correctly and have a long enough patch (which will depend on 
the overall length since length gives leverage).

Some will suggest also adding conductive grease on the elements 
overlapping.  Other may also suggest adding two (at each end) small 
bolts at 90 degrees to each other to back up or replace the clamps 
(belts and suspender mode).  I don't suggest bolts as they're hard to 
realign next time and reduce the amount of material needed at the patch 
(makes it weaker).

I've also (because it was available) taken fiberglass rod and put that 
INSIDE the two aluminum ends, with bolts to keep it in place and a clamp 
to span any distance between the ends.  It worked but isn't as 
electrically sound.

I would not use a pop rivet, it's not bonded hard enough to the elements 
(you'd still need an overlaid section), isn't strong enough over time 
and could create a weak enough contact point for RFI later.  Brazing 
also brings in a dissimilar metal and creates even more issues.

GL es 73,
Rick NK7I


On 3/16/2020 10:06 AM, Fred Jensen wrote:
> #3
>
> 73,
> Fred ["Skip"] K6DGW
> Sparks NV DM09dn
> Washoe County
>
> On 3/15/2020 3:01 PM, AE4PB at carolinaheli.com wrote:
>> I have a vertical antenna to repair and install that I believe is the 
>> same
>> as  or close to a hi-gain AV-18HT.
>> https://www.hy-gain.com/Product.php?productid=AV-18HT.
>> The main antenna vertical was cut so it could be taken down. I 
>> purchased it
>> used in hopes I could repair and install it.
>> I have two different places that require repair. Purchasing new parts 
>> for
>> the element appear to approach the cost of an entirely new antenna.
>> I'm thinking of three different methods of repair but lack experience.
>> 1. I can braze the elements using aluminum brazing rods and flux.
>> 2. I can get them welded back together but am concerned that the 
>> tubing is
>> very thin.
>> 3. I can try to find tubing of sufficient size to put inside and then
>> pop-rivet/braze the pieces together.
>>
>> What do you folks suggest?
>>
>> Thanks in advance. I've collected about a fourth of the wire 
>> necessary for
>> the radials.
>>
>> Jerry D. Moore
>> AE4PB
>>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to rick.nk7i at gmail.com