Those are probably what I got and not H50s. they may very well be
higher quality.
I paid $90 each for mine. What happened to the old ones? Rust?
I hope they did not get banged up in shipment. Sometimes they get put
on a truck with no packing and get dented and don't extend properly.
73
Rob
K5UJ
On Thu, Nov 17, 2011 at 1:47 PM, N7mal <n7mal@citlink.net> wrote:
> Rob you asked:
> "" What is your vendor source for H50s? ""
>
> I just had 2 delivered yesterday from TESSCO. I'm going
> to replace 2 that have been up for almost 20 years.....
> 73
>
>
> MAL
> N7MAL
> BULLHEAD CITY, AZ
> http://www.n7mal.com
> Everyone in the world is
> entitled to be burdened
> by my opinion
>
> ----- Original Message -----
> From: Rob Atkinson
> To: towertalk@contesting.com
> Sent: Thursday, November 17, 2011 19:34
> Subject: Re: [TowerTalk] How To Avoid Telescoping Mast Colapse
> I use a pair of Tesso 50 footers at my station along with a tree and a
> 50 foot aluminum tube guyed at 33'. I have a 1/2 wave dipole for 80
> m. fed with ladder line, a second 1/2 w. dipole for 20 m. fed with
> ladder line and an Inverted L for 160. The aluminum mast also serves
> as a 1/4 w. vertical on 80 m.
>
> I don't know about the Rohn H50s but the Tessos have a threaded L
> shaped screw clamp on each section with a support bolt that passes all
> the way through the mast under each section to prevent collapse. I.e,
> it is _not_ relying on friction only, to stay extended.
>
> What is your vendor source for H50s? I am surprised they are
> available as I thought they were getting hard to find. Also, I think
> they give a true 50 foot height as each section is a little longer
> than 10 feet to account for the nesting in the next lower section. On
> one of mine, I removed the top section to get a stronger 40 foot mast.
>
> Wire does not present much wind load (unless you use something huge
> like AWG 8 or unless it ices up and then all bets are off). You can
> take liberties therefore.
>
> You will find that working with telescoping masts is kind of nasty.
> After I got mine up I said never again. You may have an easier
> go--you might have some help, or have more strength than I have. Wear
> work gloves and extend them on the ground first, just to make sure
> they pull out and there are no problems. have a tub of axle grease in
> case the sections need some more lubrication. _Never_ work with them
> with bare hands. you will be surprised at how fast a section can free
> up and shoot inward catching your hand. I found it helpful to drive
> in a metal fence post and clamp the unextended mast to it where I
> planned to put it, with s.s. hose clamps to hold it while I guyed off
> the bottom section. Once that is done you can lean a ladder on on it
> and get up high enough to start pushing it up but make sure it is a
> calm day. have your anchors in and guys on the mast and visegrips at
> the anchors ready to use to clamp the guys. Leave the fence post
> there as a safety anchor with the bottom of the mast on a brick or
> metal plate. When you extend a mast the guy rings may ride up with
> the sections. Be ready to work them back down by pulling on the guy
> ropes.
>
> You should use earth screw anchors but you can get by in most cases
> with the hardware store variety and not the large more expensive
> version from Glen Martin or Rohn. Just check them after a couple of
> years below grade to see how they are holding up. Be prepared to
> replace them. This is never the case with a tower but a push up mast
> is okay. a pipe in the ground at a right angle to the guy will work
> toward the guy through the earth when under tension and will never
> prevent slack in the line. It might be okay if in concrete but an
> earth screw in line wtih the guy is so much easier. Have some rebar
> or crow bar to use to turn them through rocks.
>
> I started out guying my masts with clips and thimbles but they are a
> PITA when it comes to retensioning the guys. I now simply use Dacron
> 3/16" diameter. It holds up perfectly fine and has the advantage of
> being RF transparent. I tie it to the guy rings on the masts with a
> bowline knot.
> ( http://www.radioworks.com/ninstallant.html has a drawing of it, or
> used to). It will stretch at first so it has to be retensioned. I
> loop it through the earth screw eye with no thimble or clips. Instead
> I tension it and clamp it with a cheap lightweight visegrip. You can
> get clamping pliers knockoffs that are okay for this at big box
> discount stores like Menards. Eventually they rust so you have to
> oil them up before releasing them if you need to. I have read all
> sorts of over-engineered comments frowning on this practice but I have
> been doing it for 10 years with no problems.
>
> You can also get away with an anchor distance that is as little as 1/2
> the height of the guy level for the feedpoint support mast. The
> reason is that it has no unilateral pulling force on it. All it has
> to do is hold up wire and feedline dead weight. The secret is to
> tension the guys so they keep it vertical without making them so tight
> they are like a violin E string. That much tension is not necessary.
> Also 3 way guying is okay. I would avoid if possible using an
> inverted V unless you can get the feedpoint up at 70 feet on 40 and
> the ends up 20 feet or more. The reason is a V has an average height
> of 1/2 way up between the ends and the feedpoint. If the apex is at
> 40 feet and the ends are on the ground, the working height is equal to
> a dipole flat top at 20 feet. That is why they perform more poorly
> than a flat dipole at 40 feet.
>
> If you have winds up to 100 mph it makes sense to engineer a easy to
> fix break point. With a wire antenna it is probably best to set up a
> system of marine pulleys to facilitate raising and lowering the
> antenna and feedline and using wire that will snap under icing because
> it is a lot easier to drop a wire and solder it than it is to put up
> another mast.
>
> 73
>
> Rob
> K5UJ
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