Doug, thanks for the reply. The approach I am wanting to use really is not much
work. The extension of the boom is just the slip in piece of the th-6 boom. I
already have to rebuild the truss cables, so no additional work there. Moving
the boom to mast clamp is just a few bolts. I do not want to use a longer mast
to mount the dipole above the th-11. I will if that is the only way to make it
work. I just wanted to know if anyone bade any experience with my proposed
approach.
Sent from my HTC One on the Verizon Wireless 4G LTE network
----- Reply message -----
From: towertalk-request@contesting.com
To: <towertalk@contesting.com>
Subject: TowerTalk Digest, Vol 159, Issue 27
Date: Wed, Mar 9, 2016 05:36
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than "Re: Contents of TowerTalk digest..."
Today's Topics:
1. adding a 40m dipole to a TH-11DX (Mitch)
2. Re: F12 C19XR Rivets (Bert Almemo)
3. Re: F12 C19XR Rivets (Jim Thomson)
4. rotating tower hardware : EU (Richard Riley)
5. adding a 40m dipole to a TH-11DX (kr2q@optimum.net)
----------------------------------------------------------------------
Message: 1
Date: Tue, 8 Mar 2016 20:03:12 -0800
From: "Mitch" <mskobier@charter.net>
To: <towertalk@contesting.com>
Subject: [TowerTalk] adding a 40m dipole to a TH-11DX
Message-ID: <000001d179b8$998d6960$cca83c20$@net>
Content-Type: text/plain; charset="us-ascii"
All,
I will be putting up a tower in the next few months, and an
finalizing the antenna system I want to put on top. I already have a TH-11DX
that will be the main antenna for the upper HF bands, and dipoles for most
everything else. I found a design on the net by K6IF that I am considering
constructing for 40m. I have a scrap TH-6DX that I can scavenge enough
material to build the dipole. I plan on feeding it separately from the
TH-11DX. I do not want to mount the 40m dipole on the mast above or below
the TH-11DX. What I am currently considering is lengthing the TH-11DX boom
about 4 ft to the rear, and mounting the 40M dipole on the boom extension
behind the 20m reflector. Of course, I will have to move the mast mounting
point to the rear approx 2ft and extend the truss cables to take the extra
length. Anyway, that is the current plan. I have searched the archives, and
have not found any posts in regards to this type of setup with this HF beam.
I am concerned about interference to the 15m portion of the TH-11DX. I think
the 12m driven element should "act" as a reflector and shield the 15m
section from the 40m dipole. I am not very well versed in antenna modeling,
and have not been able to find a NEC profile for the TH-11DX that I could
play with. So, with all of that said, is there any reason this should not
work? I look forward to hearing what the group has to say
Thanks
Mitch KJ7JA
------------------------------
Message: 2
Date: Wed, 9 Mar 2016 00:09:45 -0500
From: "Bert Almemo" <balmemo@sympatico.ca>
To: "'Jim Thomson'" <jim.thom@telus.net>, <towertalk@contesting.com>
Subject: Re: [TowerTalk] F12 C19XR Rivets
Message-ID: <20160309050930.VZWA18724.torspm02.bell.net@BertofficePC>
Content-Type: text/plain; charset="us-ascii"
Jim,
While I agree with most of you're writing I think you'll be hard pressed to
get a solid 9 square inches of surface contact in your 1 inch tube with 3
inches of overlap. Maybe if you put in a lot of SS screws or rivets at the
joint. If you're using any kind of joint compound, like Penetrox, you need a
certain pressure to make a good contact, as I'm sure you know. SS hose clamp
+ SS screws has been a good combination for me.
Bert VE3NR
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of Jim
Thomson
Sent: Tuesday, March 08, 2016 10:46 PM
To: towertalk@contesting.com
Subject: [TowerTalk] F12 C19XR Rivets
Date: Tue, 8 Mar 2016 15:22:32 -0500
From: "Bert Almemo" <balmemo@sympatico.ca>
To: "'Roger \(K8RI\) on TT'" <K8RI-on-TowerTalk@tm.net>,
<towertalk@contesting.com>
Subject: Re: [TowerTalk] F12 C19XR Rivets
I learned long time ago that using pop rivets, blind or not, don't make for
a good electrical connection. For all antennas, using aluminum tubing, I've
used self tapping screws for the last 30 yrs and it's served me well. It's
also much easier to take antennas apart and put them together again using
screws. As always, OMHO!
73 Bert, VE3NR
## The electrical connection is between the mating aluminum tube surfaces,
not the rivets/
self tapping screws. A 1 inch OD al tube, with say a 3 inch overlap, will
have 9 square
inches of surface contact. Unless the self tapping screw is SS, it will
rust. If it is SS, then
you have the dissimilar metal issue. Mosely etc, uses SS self tapping
screws, and they work
just fine. Heck, I used a single slot + SS hose clamps for several years
on my hb yagis...and
they worked just fine, with 100% of the RF flowing through the mating
surfaces. Hy-gain, wilson
etc, used those compression clamp assys....which I just hate with a passion.
Local fellow here had a
hy-gain 204BA up 100 ft near a cliff edge, and after a few years, some of
the tips and inner sections
were just about ready to pop right out. They had migrated outboard quite a
bit. Same fellow also
had the old KLM 4 el 40m yagi......and it self destructed. It was new at
the time. He ended up
buying a bag of SS self tapping machine screws, and drove em in everywhere.
Problem solved
with the ele migration problem. Next problem was the KLM 40 eles came right
off the boom.
The 'fix' for that was to use multiple SS hose clamps to hold the lexan
brackets to the boom.
Then drive SS self tapping screws through the slots on the SS hose clamps.
## I have never seen SS self tapping machine screws ever loosen up, they
seem to hold stuff
together quite well, just don't crank em in too tight, into al tubing,
such that they strip out.
Jim VE7RF
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------------------------------
Message: 3
Date: Tue, 8 Mar 2016 22:17:48 -0800
From: "Jim Thomson" <jim.thom@telus.net>
To: "Bert Almemo" <balmemo@sympatico.ca>, <towertalk@contesting.com>
Subject: Re: [TowerTalk] F12 C19XR Rivets
Message-ID: <E4055ABA931F4C76A39A22F7DD53DDEB@JimPC>
Content-Type: text/plain; format=flowed; charset="UTF-8";
reply-type=original
@@@ Stainless steel does not conduct RF worth a damn. F12 uses 12-24 SS
screws
to make the balun connections... between a pair of SS nuts and SS
flatwashers. I also tried the same
stunt, using SS for connections to a vac tune cap, bad news. Where RF has
to flow through a screw,
brass, silver plated brass, or phosphor bronze screws works a lot better.
But we are talking about using screws
to mash two surfaces together, in which case, anything will work. F12
tried using 8 ga SS solid wire to make the
hairpin coil on a 40m yagi, more bad news. The coil turned black, dead
center in the middle of the coil, where
the current is highest. For a laugh, I tried SS 8 ga SS solid wire for
a 40m tank coil in my hb linear, what a disaster.
Also tried AL tubing, like the soft 3003-H0 alloy, for a 20m tank coil, in
the same linear, also with disastrous results.
@@ Im not about to replace the solid al rivets on any of my f12 yagis with
SS self tapping sheet metal screws anytime soon.
f12 puts the 1st rivet almost at the end of the joint, close to the edge,
( too close, it should be 1.5 diameters away from any edge)..
so no way to install a SS hose clamp. Hose clamps wont even work unless
you have at least one slot cut into the outer tube.
So its either rivets, ss self tapping sheet metal screws... or slots + SS
hose clamps. If slots + hose clamps + screws used,
the hose clamp would have to be cranked down good and tight..1st, b4 any SS
self tapping screws being installed.
@@ SS machine screws + SS nylocks.... at right angles to each other, will
also work good. Bottom line is, use whatever
works for you. If starting from scratch, then you have more options. BTW,
for you folks that buy AL tubing from DX eng,
they now offers AL tubing with NO slots on either end. b4, DX eng sold
their tubing with 4 x slots..a slot every 90 degs,
on ONE end only. Previously, if you didn?t want to use the slots, the tube
was flipped 180 degs, so the slotted end
was stuffed into the next bigger tube...never to be seen again. The
advantage to the... no slots at all option, is the
tubing is now even cheaper to buy. EG: .375 OD x .058 wall x 3 ft
long, is only $1.48 ( 6063-T832 alloy, which is the
same 40 ksi yield strength as the more expensive 6061-T6 alloy). Yield
strength X section modulus = bending moment.
Jim VE7RF
-----Original Message-----
From: Bert Almemo
Sent: Tuesday, March 08, 2016 9:09 PM
To: 'Jim Thomson' ; towertalk@contesting.com
Subject: RE: [TowerTalk] F12 C19XR Rivets
Jim,
While I agree with most of you're writing I think you'll be hard pressed to
get a solid 9 square inches of surface contact in your 1 inch tube with 3
inches of overlap. Maybe if you put in a lot of SS screws or rivets at the
joint. If you're using any kind of joint compound, like Penetrox, you need a
certain pressure to make a good contact, as I'm sure you know. SS hose clamp
+ SS screws has been a good combination for me.
Bert VE3NR
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of Jim
Thomson
Sent: Tuesday, March 08, 2016 10:46 PM
To: towertalk@contesting.com
Subject: [TowerTalk] F12 C19XR Rivets
Date: Tue, 8 Mar 2016 15:22:32 -0500
From: "Bert Almemo" <balmemo@sympatico.ca>
To: "'Roger \(K8RI\) on TT'" <K8RI-on-TowerTalk@tm.net>,
<towertalk@contesting.com>
Subject: Re: [TowerTalk] F12 C19XR Rivets
I learned long time ago that using pop rivets, blind or not, don't make for
a good electrical connection. For all antennas, using aluminum tubing, I've
used self tapping screws for the last 30 yrs and it's served me well. It's
also much easier to take antennas apart and put them together again using
screws. As always, OMHO!
73 Bert, VE3NR
## The electrical connection is between the mating aluminum tube surfaces,
not the rivets/
self tapping screws. A 1 inch OD al tube, with say a 3 inch overlap, will
have 9 square
inches of surface contact. Unless the self tapping screw is SS, it will
rust. If it is SS, then
you have the dissimilar metal issue. Mosely etc, uses SS self tapping
screws, and they work
just fine. Heck, I used a single slot + SS hose clamps for several years
on my hb yagis...and
they worked just fine, with 100% of the RF flowing through the mating
surfaces. Hy-gain, wilson
etc, used those compression clamp assys....which I just hate with a passion.
Local fellow here had a
hy-gain 204BA up 100 ft near a cliff edge, and after a few years, some of
the tips and inner sections
were just about ready to pop right out. They had migrated outboard quite a
bit. Same fellow also
had the old KLM 4 el 40m yagi......and it self destructed. It was new at
the time. He ended up
buying a bag of SS self tapping machine screws, and drove em in everywhere.
Problem solved
with the ele migration problem. Next problem was the KLM 40 eles came right
off the boom.
The 'fix' for that was to use multiple SS hose clamps to hold the lexan
brackets to the boom.
Then drive SS self tapping screws through the slots on the SS hose clamps.
## I have never seen SS self tapping machine screws ever loosen up, they
seem to hold stuff
together quite well, just don't crank em in too tight, into al tubing,
such that they strip out.
Jim VE7RF
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
------------------------------
Message: 4
Date: Wed, 9 Mar 2016 08:01:30 +0000
From: Richard Riley <Richard.Riley@tango.hr>
To: "towertalk@contesting.com" <towertalk@contesting.com>
Subject: [TowerTalk] rotating tower hardware : EU
Message-ID:
<10A759309FD8094DA8BF4AD6BACCE35D926AFBB6@dc.tango.internal>
Content-Type: text/plain; charset="Windows-1252"
Hello all,
I am in the market for:
2 rotating-tower guy-rings (tower is triangular 500mm profile)
a complete base&motor(including controller)
cca. 160m of Parafil or equivalent (rated MBL 115kN)
..and am collecting quotes.
For the rotating hardware I am aware of 4O3A and K0XG?are there any other
businesses producing such?
For the guys, I was previously in touch with linearcomposites.com in the UK for
Parafil (aka Phillystran), Fibremax.nl for aramid Twaron and more recently with
Mastrant (who recommended their D-F2 product), can anyone recommend any others?
The above is for the first (and smallest) of 5 towers we plan to erect here, so
I want to get it right first time, and buy from the same providers when the
other four go up, in the coming years?
Your feedback appreciated direct to my email. I?ll summarize responses or the
benefit of all.
rgds
9a1tt
PS. my apologies to those subscribed to the cq-contest reflector, who already
received this request there.
Richard Riley
[http://www.tango.hr/images/tango.png]<http://tango.hr>
tango komunikacije d.o.o.
Strojarska cesta 22
10000 - Zagreb - Croatia
office: +385(0)1 5494 301
fax: +385(0)1 5494 315
EU VAT#: HR73112507864
------------------------------
Message: 5
Date: Wed, 09 Mar 2016 13:36:44 +0000 (GMT)
From: kr2q@optimum.net
To: towertalk@contesting.com
Subject: [TowerTalk] adding a 40m dipole to a TH-11DX
Message-ID: <e53cda9814da.56e026ec@optonline.net>
Content-Type: text/plain; charset=us-ascii
I would be concerned about the interaction with 15m too.
Your approach seems like a lot of work.
Have you considered mounting it on the mast, but parallel to the boom?
I did this with a TH6DXX in the 1970's and it worked great.
Of course, you have to remember that it is 90 degrees "off" when rotating the
antenna.
Would be a much simpler installation.
GL!
de Doug KR2Q
------------------------------
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------------------------------
End of TowerTalk Digest, Vol 159, Issue 27
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