[Boatanchors] Antenna sealing questions, silastic?

[mikea]

On Wed, Mar 09, 2016 at 11:18:00PM +0000, Phil wrote:
> Hi All,
> Been doing antennas many, many years, but I still have a question, maybe 
> 2 :)  Yeah, this isn't boatanchors, but there are a lot of antenna 
> experts out here.
> 
> I just recently installed a TYT TH-9800 (Quad Band clone of the Yaesu 
> FT-8900) in both the shack and the Ford "Screw".  Both radios are 
> installed and get excellent audio & signal reports.  I don't expect to 
> use the 10M & 6M (FM) bands, just got them to use for 2M/440. They were 
> only $6 more than the TYT 7800 dual band radios (clone of the Yaesu 8800).
> 
> While I ordered the radios I also ordered a new dual band base antenna, 
> the Tram 1481 (17 foot colinear).  Supposed to be a pretty good antenna, 
> but if I'd read the reviews first I might have chosen a different model 
> as some users have had problems with water ingress (sp?), even though 
> they said they sealed it well. Others say they've never had a problem 
> with it.
> 
> Anyway, I didn't think to order coax seal, and RadiosShack is totally 
> gone from the Central Valley here in Calif.
> 
> The antenna has 3 fiberglass sections that screw together and is 
> supposed to have factory seals, which apparently don't do the job.  Many 
> folks seal the sections with Coax seal or other methods, and "Silastic' 
> repeatedly came up.  WHAT pray tell is "Silastic".  It sounds like 
> something a woman might wear.  I sort of thought about heavily wrapping 
> the joints with black plastic tape and them put a coat of clear RTV over 
> that.  Those are things I can obtain locally.
> 
> OR is there something else available at the usual hardware store (ACE, 
> Lowes etc) that might be better, especially to seal the coax fitting at 
> the base. . .
> 
> By the way, the feedline I bought for this antenna is a 25 foot length 
> of LMR-400 with factory PL-259's, bought from MPD Digital it looks like 
> a VERY good product!  It's my first experience with LM-400, I didn't 
> realize it was as stiff as it is. IF I do the install RIGHT it should be 
> good for a long time (I'm getting too old to have to re-do antennas and 
> push-up poles very often).
> 
> We DON'T get a lot of rain here (other than this El Nino year) and seem 
> to be in a perpetual drought, but once I put the antenna up I don't want 
> to have to take it back down to letthe droplets of water that might 
> collect in the bottom dry out.
> 
> Are there better ideas here?

My memory tells me that "Silastic" is a brand name for one Room-Temperature
Vulcanizing (RTV) silicone sealant. 

-- 
Mike Andrews, W5EGO
mikea at mikea.ath.cx
Tired old sysadmin