The following is a summary of the replies to my query on loose KT34XA
shorting straps. Thanks to everyone for all the good information.
I now have what appears to be at least four good fixes to
chose from. BTW, if anyone wants copies of Frederico, IK3UMT's GIF
files, let me know, I can send them to you (I couldn't post to
towertalk with attachments).
Mike, W4EF............
P.S. I won't use brass - grin grin
----------
From: Michael Tope[SMTP:W4EF@pacbell.net]
Sent: Sunday, October 03, 1999 2:28 PM
To: 'TowerTalk'
Subject: [TowerTalk] Shorting Straps on KT34XA
I am in the process of preparing a used KLM KT34XA for
re-installation on the tower. While I was cleaning-up
and inspecting the elements, I noticed that it was
difficult to get the shorting straps in the linear loading
sections to fit tight around the capacitor tubes (I think
these are the so called type "C" straps), especially when
they are coated with no-alox which is somewhat slick.
This loose fit concerned me as it was my understanding that
no-alox needs to be under pressure to work reasonably well.
As a result, I picked up some 10 mil brass shim stock at the
local hardware and shimmed a couple of the strap terminations
so that they are now snug around the capacitor tubes.
Unfortunately, this is a rather tedious process.
Anybody out there know of a better solution, or am I overkilling
this thing? I have 5 more elements to do, so any labor saving hints
would be appreciated.
Thanks,
Mike, W4EF.........
----------
From: William C Maddock[SMTP:n4zi@juno.com]
Sent: Friday, October 08, 1999 2:59 PM
To: W4EF@pacbell.net
Subject: Re: [TowerTalk] Shorting Straps on KT34XA
Michael,
I know I am a bit late with this reply, but will send it anyway! I
currently have 3 KT34XA's
of which I am currently rebuilding. I have 1 in it's final stages now,
ready with the exception
of some final tuning!
As for your tolerance problem, I wouldn't recommend using shims at all,
especially
of a disimilar metal! Your best bet would be to remove the straps and
gently squeeze
them down with a pair of channel locks or pliers to get them to fit as
tight as possible!
KLM makes a new silver compound or you can use what you have! Be sure to
check
the continuity across the joint as it should be no more than 0.5 ohm or
less! I would
recommend using aluminum pop rivets 1/8" at all the joints with the
exception of those
clamping directly on the capacitors! Make sure the SWR is where you want
it before you
use the pop rivets! They will read about 50 khx low when in close
proximity to ground!
K7LXC and N0AX did some testing on the KT34XA and found them to resonate
to
low in the 15 mtr band. I have found this to be true and am triing
alternate dimensions
to get where it should be on 15 mtrs! I will email you if I come up with
something. I expect
to have my top KT34XA in place within the month. I will probably tram it
up to 50 ft level
for a more accurate SWR check before I pop rivet it!
73 de Bill N4ZI Atoka, TN
----------
From: K7LXC@aol.com[SMTP:K7LXC@aol.com]
Sent: Thursday, October 07, 1999 7:00 AM
To: W4EF@pacbell.net
Subject: Re: [TowerTalk] Shorting Straps on KT34XA
Hi, Mike --
A bunch of work but it should work.
>
> Speaking of metals, what are the TEK screws made from? This
> sounds like a convenient fix, but I am concerned about longevity
> of the joint. My physicist friend suggested that self tapping
> screws might be as prone to trouble as my aluminum brass shim
> sandwich depending on the choice of materials.
I don't know what the material is - maybe steel of some sort. I haven't
tried a magnet on them. I don't think rusting is a problem with them. I got a
couple of messages that maybe the TEK screws may not be suitable for your
application - you may have seen the posts. The screws may affect the
electrical properties of the antenna at that point which obviously is a
no-no. So you might be stuck with the shim route anyway.
The longevity of the joint would be longer than you and I are worried
about IMO.
Cheers, Steve K7LXC
----------
From: Jeff Singer[SMTP:k2kv@reallybig.com]
Sent: Wednesday, October 06, 1999 7:30 PM
To: Ron Youvan; ka4inm@qsl.net; towertalk@contesting.com
Subject: RE: [TowerTalk] Re: shorting straps on KLM KT34XA and other
rebuild recommendations from K3MM
This may be old hat to some, but before we put up our KLMs, we always drill
and place 1/8 inch rivets everywhere except the cap tubes. Holds it all
together for a VERY long time, and if you have to take it apart for some
reason, the rivets drill right out. Moreover, it is extremely easy to put
back together without re-measuring everything.
I've never had a KLM fall apart, and I've never had a problem with one that
couldn't be traced to human error.
73,
Jeff K2KV
----------
From: Ron Youvan[SMTP:ka4inm@gate.net]
Sent: Wednesday, October 06, 1999 6:49 PM
To: ka4inm@qsl.net; towertalk@contesting.com
Subject: Re: [TowerTalk] Re: shorting straps on KLM KT34XA and other
rebuild recommendations from K3MM
> << I've rebuilt 3 KT34XA's so far (hopefully no more...please!), and my
> recommendation is to use #6 or #8 sheet metal screws through all the clips
> joints except for the cap tube. There, use new, thicker straps you can get
> from
> KLM or make your own. >>
Hi: I have never had my KT34A higher than about 12 feet, it was detuned by
orange trees and the metal eve on the garage. (tests) It is in storage.
1. Every hole you drill in tubing weakens it. In a high vibration
application
I would rather not `drill' if I can find any better way. Air-e-o-planes are
aluminum and full of holes, but they aren't mostly tubing.
{I am not a sheet metal man, but I am not a stranger to it, I took `sheet metal
shop 3 years in school, I didn't want to take it, it was all that wasn't full,
so I
was stuck there, I enjoyed reveting and soldering though.}
2. Did every one of these antennas last over a year without any problems?
This antenna has NOT done that well so far.
I plan a annual PM on the entire (now proposed ) tower, including bringing
my beam to the ground, I wish for the clamps and bands to be `good for another
year' when I do it. (It will be up 104')
I will refresh, remove and replace all anti-Ox. when I do. I expect to replace
the
blue caps when they show signs of deterioration, I don't know how often that
will be. (lots of UV in central Florida, and bunch of heat)
I do not know what I will use to replace the old straps or of I will be able
to
find a better way to secure the connections using the original straps. The
shims
and other `fixes' that were tried to make this antenna work must go. I thought
I
might cut up the super sized bands (1/2" wide and 3 or 4' long) that I have seen
in auto parts stores etc. for the material by cutting it into 2 or 3 pieces of
suitable length (10 - 14" each) with the ends bent around to allow the `hose
bands' to be at the correct angle (perpendicular to the tubing) This `bending
the
ends,' forming the connections is what I haven't worked out yet. Perhaps I need
to
have a little piece (across the end) welded (spot or other) to the ends and put
two hose bands, one on each on each side of the clamp.
This group (& list) is what I need to (help me) kick around ideas until WE
find
an idea so good KLM starts making them our new way.
I bought this 3 or so years old antenna for $100 (they offered it to me for
50 or
75 dollars, but I wanted to help them) from a local club that had `had it' with
it. It just wouldn't keep running. Other than several blown BALUNS the straps
would not stay tight. (they replaced everything several times hoping to cure
it's
ills. (they shot-gunned it!)
It is the `high wind) two piece boom version. Tampa Florida area.
73 (= Best Regards) de: Ron ka4inm@qsl.net
VISIT my HAM WEB SITE at: http://www.qsl.net/ka4inm
using LINUX here & loving it!
----------
From: tgstewart@pepco.com[SMTP:tgstewart@pepco.com]
Sent: Wednesday, October 06, 1999 5:11 AM
To: K7LXC@aol.com
Cc: W4EF@pacbell.net; towertalk@contesting.com
Subject: Re: [TowerTalk] Shorting Straps on KT34XA
He's referring to the strap that surrounds the cap tubes, and you cant use a
screw there without possibly messing up the capacitance. If I were going to try
something like that on the cap tube, I'd preassemble the tube and strap using an
aluminum "pop rivet", rather than use a screw. As long as you did it before you
assembled the cap tube, you could make sure that you got rid of all the
shavings, etc. inside the tube before assembly, and the little tit left inside
from a rivet probably wouldnt change the capacitance all that much. You'd
probably want to be sure and cover up the rivet with some silicone and maybe
some tape to help keep water out of the cap tube assy.
However, the safest thing to do is make a new strap out of thicker material (or
get the new ones from KLM).
73, Ty K3MM
----------
From: K7LXC@aol.com[SMTP:K7LXC@aol.com]
Sent: Wednesday, October 06, 1999 12:16 AM
To: ka4inm@qsl.net; towertalk@contesting.com
Subject: Re: [TowerTalk] Re: shorting straps on KLM KT34XA
In a message dated 99-10-05 21:15:50 EDT, ka4inm@gate.net writes:
> << Anybody out there know of a better solution, or am I overkilling
> this thing? I have 5 more elements to do, so any labor saving hints
> would be appreciated. >>
>
> I have a KLM KT-34A (not X) and it has this problem, I see this as a
> design defect.
>
> My plan is to replace these "C" or "P" ? straps with stainless steel
straps
> held to
> the elements es gamma match with (all) stainless steel `avaition hose
bands'
> screw
> type radiator hose clamps/bands. I have not worked out the details, looks
> like it
> will be super sized bands (1/2" X 3') that I have seen in auto parts
stores
> etc.
> cut into 2 or 3 pieces of suitable length with the ends bent around to
allow
> the
> `hose bands' to be at the correct angle (perpendicular to the tubing.
> This bent ends, forming the leads is what I havn't worked out yet.
> I have replaced the two very short jumpers with some clamped on rings that
I
> straightened out and used, but they were able to be bent in a different
> manner.
>
> This matter must be properly addressed before I put this beast up on my
> future tower.
Yes, it's a design problem but thousands of these antennas have still
worked successfully despite it.
I would not recommend changing/substituting anything in this (or any
other) antenna. All of the parts work together in a unique way and, while you
may get away with it, spending all the time and effort to 're-invent' a part
doesn't seem like it's likely to be worth it. The designers spent MANY hours
to get it all right.
Cheers, Steve K7LXC
Tower Tech
----------
From: Ron Youvan[SMTP:ka4inm@gate.net]
Reply To: ka4inm@qsl.net
Sent: Tuesday, October 05, 1999 6:15 PM
To: towertalk@contesting.com
Subject: [TowerTalk] Re: shorting straps on KLM KT34XA
Hi:
<< Anybody out there know of a better solution, or am I overkilling
this thing? I have 5 more elements to do, so any labor saving hints
would be appreciated. >>
I have a KLM KT-34A (not X) and it has this problem, I see this as a design
defect.
My plan is to replace these "C" or "P" ? straps with stainless steel straps
held to
the elements es gamma match with (all) stainless steel `avaition hose bands'
screw
type radiator hose clamps/bands. I have not worked out the details, looks like
it
will be super sized bands (1/2" X 3') that I have seen in auto parts stores etc.
cut into 2 or 3 pieces of suitable length with the ends bent around to allow the
`hose bands' to be at the correct angle (perpendicular to the tubing.
This bent ends, forming the leads is what I havn't worked out yet.
I have replaced the two very short jumpers with some clamped on rings that I
straightened out and used, but they were able to be bent in a different manner.
This matter must be properly addressed before I put this beast up on my future
tower.
73 (= Best Regards) de: Ron ka4inm@qsl.net
VISIT my HAM WEB SITE at: http://www.qsl.net/ka4inm
using LINUX here & loving it!
----------
From: K7LXC@aol.com[SMTP:K7LXC@aol.com]
Sent: Tuesday, October 05, 1999 6:40 AM
To: W4EF@pacbell.net; towertalk@contesting.com
Subject: Re: [TowerTalk] Shorting Straps on KT34XA
In a message dated 99-10-03 17:30:31 EDT, W4EF@pacbell.net writes:
> I am in the process of preparing a used KLM KT34XA for
> re-installation on the tower. While I was cleaning-up
> and inspecting the elements, I noticed that it was
> difficult to get the shorting straps in the linear loading
> sections to fit tight around the capacitor tubes (I think
> these are the so called type "C" straps), especially when
> they are coated with no-alox which is somewhat slick.
> This loose fit concerned me as it was my understanding that
> no-alox needs to be under pressure to work reasonably well.
> As a result, I picked up some 10 mil brass shim stock at the
> local hardware and shimmed a couple of the strap terminations
> so that they are now snug around the capacitor tubes.
> Unfortunately, this is a rather tedious process.
Big UGH to that. Then you've got dissimilar metals to deal with too.
>
> Anybody out there know of a better solution, or am I overkilling
> this thing? I have 5 more elements to do, so any labor saving hints
> would be appreciated.
The looseness of these straps is well documented. After you've got it
reassembled and working to your satisfaction, I would suggest using a TEK
screw to pin everything together. A TEK screw is a chisel-point self-tapping
screw that will go into aluminum in a couple of seconds. I prefer the
Phillips head variety as they are easier to drive with my cordless drill.
They don't have to be very long. This provides a good redundant electrical
connection as well as mechanical connection.
Cheers, Steve K7LXC
Tower Tech
----------
From: WBH3@daimlerchrysler.com[SMTP:WBH3@daimlerchrysler.com]
Sent: Monday, October 04, 1999 9:13 AM
To: towertalk@contesting.com
Cc: Michael Tope
Subject: Re: [TowerTalk] Shorting Straps on KT34XA
I just gave up and riveted them
----------
From: J. Parise[SMTP:w1uk@downcity.net]
Sent: Monday, October 04, 1999 4:08 PM
To: Michael Tope
Subject: Re: [TowerTalk] Shorting Straps on KT34XA
Many have found drilling a small hole through the strap into the element and
installing a stainless steel screw added another level of insurance.
73 -- Jim W1UK
----------
From: Kurszewski Chad-WCK005[SMTP:Chad.Kurszewski@motorola.com]
Sent: Monday, October 04, 1999 8:20 AM
To: Michael Tope
Subject: RE: [TowerTalk] Shorting Straps on KT34XA
> Anybody out there know of a better solution, or am I overkilling
> this thing? I have 5 more elements to do, so any labor saving hints
> would be appreciated.
>
I rebuilt two KT-34XA's last year.
I bent the straps (to collapse them slightly) so that they
would provide a tighter fit.
I also followed that up with a stainless steel sheet-metal
screw through the strap into the element. Do NOT do this
on the straps that connect to the capacitor cans. Only on
the straps going to element pieces. These screws dramatically
increased the rigidity of the element. As you noted, with
nolox greasing up the joints, it didn't seem like a good
connection since they are easily moved/twisted. By adding
this screw, the mechanical and electrical 'soundness' is much
improved.
Chad WE9V
KT-34XA stack at 50/100'
----------
From: tgstewart@pepco.com[SMTP:tgstewart@pepco.com]
Sent: Monday, October 04, 1999 7:38 AM
To: Michael Tope
Subject: Re: [TowerTalk] Shorting Straps on KT34XA
You can order new straps from KLM. The sheet stock they are using for the clips
now is of a heavier gauge material, and less likely to stretch out over time.
Of course you can always bend your own...
73, Ty K3MM
----------
From: Tom Mannix[SMTP:tmannix@bellsouth.net]
Sent: Monday, October 04, 1999 2:40 AM
To: Michael Tope
Subject: Re: [TowerTalk] Shorting Straps on KT34XA
No,no,no BRASS!! Too much bi-metal corrosion possibility. I have done many
of these and just pinched the strap a hair with pliers to make it more
secure. Noalox is fine - you will be happy about it the next time you take
it down for service/
73,Tom,WA4YLD
----------
From: Pat Barthelow[SMTP:aa6eg@hh.tmx.com]
Sent: Sunday, October 03, 1999 7:12 PM
To: Michael Tope
Cc: 'TowerTalk'
Subject: Re: [TowerTalk] Shorting Straps on KT34XA
Hi Mike,
I've been through the drill, on the KT-34, too. REAL TEDIOUS...
If I did it again, I would contact KLM and replace the old straps with
new. I am a bit concerned about your using brass shim stock, due to the
dissimilar metals/corrosion problems they might cause.
I got aluminum sheet shim stock at Orchard Supply, and used it...THOUGH I
suspected The shim stock was too shiny to be just plain aluminum, and just
as I suspected, it was anodized..... a great high resistance insulator
when probed on the surface with a VOM. I had to scotchbright the
perfectly clear anodized inuslating layer off the surface before I used
it for shims. The anodized layer was not easy to remove.
73, DX, de
Pat, AA6EG/N6IJ;
aa6eg@hh.tmx.com;n6ij@hotmail.com
599 DX Drive, Marina CA 93933
See us on the web: www.polkinghorn.org/n6ij
"The Contest Station from the Government"
----------
From: Federico Zanini IK3UMT[SMTP:rfmaster@tin.it]
Reply To: Federico Zanini IK3UMT
Sent: Sunday, October 03, 1999 4:46 PM
To: Michael Tope
Subject: R: [TowerTalk] Shorting Straps on KT34XA
Hi Michael
I own a kt34xa and it was new (not used)
The antenna is excellent but klm puts no care in shorting straps...
I dont know what straps you are referring to (here is a drawing too) by the
way i've encountered
problems in mechanical joint of "A" straps on 3/4" capacitor tubes
(tightening screws 'til the
end , straps do not make "spring" effect but are still free to rotate around
tubes..)
Solutions are :
1) buy a strip of aluminium and bend it around capacitor tubes to increase
overall diameter,
2) (my solution) buy some inox screw and , after a small drill hole, tighten
straps for a good
clamp (as described in second draw i've sent) it's probably tedious
too but sure !
All "B" and "C" straps were fixed with little inox screws too ,first of any
tuning (what a risk !!!)
fortunately , all dimensions are ok , no tune was necessary and antenna
works well even after
several years.
That's the story....i wish i've understood your problem.. let me know if you
need more infos
Best 73 and good DX !!
IK3UMT - Federico
ik3umt@gw.ir3ip.ampr.org
Take a look at: http://gw.ir3ip.ampr.org
----------
From: W6ou@aol.com[SMTP:W6ou@aol.com]
Sent: Sunday, October 03, 1999 3:22 PM
To: W4EF@pacbell.net
Subject: Re: [TowerTalk] Shorting Straps on KT34XA
Mike - This was another screwup by KLM. The diameter of the wrap-around
clamped ends is too large. You can purchase the correct straps which fit
tightly from the current manufacturer of the KT34 whoever that is.
----------
From: Gene S.[SMTP:k5gs@att.net]
Sent: Sunday, October 03, 1999 3:18 PM
To: Michael Tope
Subject: Re: [TowerTalk] Shorting Straps on KT34XA
I've done exactly what you're doing, it works fine....
Only difference is I used thin aluminun shim stock..
I like the straps to be tight.....
73,
Gene S.....
----------
From: Larry L Moore[SMTP:km6iu@jps.net]
Sent: Sunday, October 03, 1999 3:01 PM
To: Michael Tope
Subject: Re: [TowerTalk] Shorting Straps on KT34XA
We have pop rivited these with success. Never happy with the factory
clamps. 73 Larry km6iu
Michael Tope wrote:
--
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|