[TowerTalk] Question about force 12 c-4

[Roger (K8RI)]

> Steve, I thought I read that the F-12 rivets ( the rivets used by F-12 are
> not your everyday garden type...no holes in the center or something like
> that....) give the entire antenna somewhat less wind resistance ( and

They are a closed end, pop rivett.  The closed end is on the inside. All the 
ones I've seen look like other pop rivetts on the outside.  Even if they 
were smooth on the outside, the area is so small it should make little 
difference aerodynamically in an antenna as they make no not iceable 
difference in airplanes. The Sonex uses pop rivetts throughout and with the 
larger engine will cruise near 200 MPH.

"Theoreticaly" the closed end will prevent water from seeping in, but you 
still have the outside junction between the rivett and element. So, again in 
practice I doubt if it makes much if any difference.

the strongest pop rivetts are the "Cherrymax" that are allowed for some 
applications in certified aircraft. However most aircraft rivetts have to be 
"bucked" or set and are either round or flat head. Round head are used quite 
often even in high performance aircraft like the Bonanzas that cruise near 
200 MPH, give or take depending on model.

> survivability? ) than do clamps or screws, washers and nuts.  What do you
> make of that?  - Mike

A properly sized and installed rivett creates a much more uniform connection 
than a screw and gives a cleaner connection than clamps. However the rivewtt 
needs to be the proper length and diameter for the thickness of the material 
being joined and the hole has to be round with clean edges and of the proper 
size. Unlike metal screws, rivetts are unlikely to work loose and make a 
better all around joint. (OTOH in 46 years as a ham I've never had a metal 
screw loosen up in an antenna.  Stainless steel hose clamps will make a more 
sound split tube to tube connection, but rivets are a few cents each, ae 
faster to install with less effort. The SS clamps may run from 50 cents to a 
dollar or two for element size clamps and again the SS clamps should be 
properly sized. That and the hose clamps just don't make the antenna look as 
elegant as rivetts. <:-))

Roger (K8RI)
>
> -----Original Message-----
> From: towertalk-bounces at contesting.com
> [mailto:towertalk-bounces at contesting.com]On Behalf Of K7LXC at aol.com
> Sent: Friday, May 11, 2007 5:15 PM
> To: towertalk at contesting.com; k2vi at cox.net
> Subject: Re: [TowerTalk] Question about force 12 c-4
>
>
>
> In a message dated 5/11/2007 12:47:35 P.M. Pacific Daylight Time,
> towertalk-request at contesting.com writes:
>
>>  I realize the forch 12 antenna preforms excellent but my  problem with
> force 12 is the rivets for the element construction.
>
>    Why would they be a problem? Umm, airplanes are  held together with
> them.
>
>    Granted I would recommend additional rivets in  windier environments 
> but
> other than that, they are a terrific way to connect  element pieces. I 
> don't
> see a downside.
>
> Cheers,
> Steve       K7LXC
> TOWER TECH
>
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