Hi Marc, you should be fine with the 240N at 4 meters from the C31. I have a
Mag340N 8 feet from my upper C31. Perfect. I have a couple friends with the
Mag240N and have heard of no modifications, tuning issues etc. AND they love
the performance. You should enjoy this setup. GL, 73, Tommy WD4K
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of
towertalk-request@contesting.com
Sent: Monday, September 11, 2006 8:47 AM
To: towertalk@contesting.com
Subject: TowerTalk Digest, Vol 45, Issue 50
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Today's Topics:
1. Nasty RF problem.... (Jim Jarvis)
2. Rohn 45 Rotor plate u-bolts (N2TK, Tony)
3. Re: Rohn 45 Rotor plate u-bolts (wa3afs@inav.net)
4. Re: Rohn 45 Rotor plate u-bolts (K8RI on TowerTalk)
5. Grounding specifics (Peter Dougherty)
6. f12- magnum 240N (Marc Wullaert ON4MA)
7. 90' sky needel (Mac McCullough)
8. Re: 90' sky needel (Doug Rehman)
9. Grounding Help (Phil Camera)
----------------------------------------------------------------------
Message: 1
Date: Sun, 10 Sep 2006 21:00:05 -0400
From: "Jim Jarvis" <jimjarvis@verizon.net>
Subject: [TowerTalk] Nasty RF problem....
To: <towertalk@contesting.com>
Message-ID: <AEEBLJJLFDELDONOLOODGEBBCHAA.jimjarvis@verizon.net>
Content-Type: text/plain; charset=iso-8859-1
Off reflector, I sent him back to Airstream. They own the problem.
It may be a shielding/grounding problem.
There is no way, in the near field, that he's going to find a sweet
spot to null out the rfi.
Short and sweet: One airstream rig works, one does not, in the environment.
See Airstream.
N2EA
FCC Licensed, commercial and amateur services
been there, done that, and it doesn't pay enough!
------------------------------
Message: 2
Date: Sun, 10 Sep 2006 21:21:50 -0400
From: "N2TK, Tony" <tony.kaz@verizon.net>
Subject: [TowerTalk] Rohn 45 Rotor plate u-bolts
To: "Towertalk (E-mail)" <towertalk@contesting.com>
Message-ID: <000001c6d540$a8dc9750$6517a8c0@mattson.com>
Content-Type: text/plain; charset=iso-8859-1
I am looking for replacement u-bolts for a Rohn 45 rotor plate. I would
prefer stainless or galvanized. I need 3.
The old ones seems to be 1.375" id, about 2-2.5" long and 1/4-20. Any idea
where I can get these?
Tnx
N2TK, Tony
------------------------------
Message: 3
Date: Sun, 10 Sep 2006 21:36:18 -0500
From: wa3afs@inav.net
Subject: Re: [TowerTalk] Rohn 45 Rotor plate u-bolts
To: "N2TK, Tony" <tony.kaz@verizon.net>, "Towertalk (E-mail)"
<towertalk@contesting.com>
Message-ID: <45048552.29742.5DCFD3C@wa3afs.inav.net>
Content-Type: text/plain; charset=US-ASCII
I have had very good luck with obtaining stainless hardware from FASTENAL
which seems to have stores in many
places. Check www.fastenal.com or your local phone book which has pointers
to their stores.
I have bought from them in Cedar Rapids, IA and Albany, NY and was very
satisfied at each.
73
-- Bruce
On 10 Sep 2006 at 21:21, N2TK, Tony wrote:
> I am looking for replacement u-bolts for a Rohn 45 rotor plate. I would
> prefer stainless or galvanized. I need 3.
> The old ones seems to be 1.375" id, about 2-2.5" long and 1/4-20. Any idea
> where I can get these?
> Tnx
> N2TK, Tony
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
------------------------------
Message: 4
Date: Sun, 10 Sep 2006 22:51:08 -0400
From: "K8RI on TowerTalk" <K8RI-on-TowerTalk@tm.net>
Subject: Re: [TowerTalk] Rohn 45 Rotor plate u-bolts
To: "Towertalk (E-mail)" <towertalk@contesting.com>
Message-ID: <001f01c6d54d$27fba880$6500a8c0@SecondOne>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
Check your local yellow pages as well as the internet for industrial
fasteners. Here in Midland we have Prime Fastener which is a part of Alma
Bolt. I know they have a web site, but not if they have a minimum order.
The U-bolts *might * also be available from DX Engineering. They have a lot
of U-bolts and mast clamps as well as the inserts that go between the flat
plate and tower leg.
Hit Google up for galvanized u-bolt sales or sources and you should find
hundreds of sources.
Roger Halstead (K8RI and ARRL 40 year Life Member)
N833R - World's oldest Debonair CD-2
www.rogerhalstead.com
>I am looking for replacement u-bolts for a Rohn 45 rotor plate. I would
> prefer stainless or galvanized. I need 3.
> The old ones seems to be 1.375" id, about 2-2.5" long and 1/4-20. Any idea
> where I can get these?
> Tnx
> N2TK, Tony
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
------------------------------
Message: 5
Date: Sun, 10 Sep 2006 23:55:19 -0400
From: Peter Dougherty <w2irt@comcast.net>
Subject: [TowerTalk] Grounding specifics
To: towertalk@contesting.com
Message-ID: <7.0.1.0.2.20060910233853.07877328@comcast.net>
Content-Type: text/plain; charset="us-ascii"; format=flowed
Hi all,
I'm hoping to get some wire and ground rods down within the next
couple of weeks but I'm not sure what type of wire specifically I
should be using. I'm trying to find a way to illustrate a plan of my
QTH, but essentially I'm going to encircle 3 sides of the house (4th
side is a long driveway), and a small circle around the base of my
70' crank up tower with each of the 3 legs connected to a ground rod
and in a circle, which in turn will be connected to the larger length
of wire around the house.
To go around the house and tie into the service ground, it looks like
I need about 100-150' of wire (I haven't measured exactly yet, but
it's close to that).
Couple of questions:
1) Should I also run additional "radials" emanating from this
arrangement, out into the back yard, or does that make a significant
difference?
2) What gauge and type of wire should be used for this project? In
what I've read, I've seen many different opinions. 6 solid, 4 solid,
10 stranded, etc? And I'm guessing this will obviously need to be
bare copper, not insulated! My electrician is clueless about this
kind of grounding, of course -- he thinks I'm crazy, believing one or
two ground rods bound to AC ground are all I need!
3) Will I likely be OK about 3 to 4" below the ground? I don't have a
way to get 'em much deeper than that unless I hire a contractor,
something that's not really in the budget at this point if not 100%
necessary.
4) Where can I buy the proper stainless steel hardware to take a
copper strap from a tower leg (and for that matter, a good place for
copper strapping nowadays!), then bind it to a 5/8" ground rod?
5) I'd really like to Cadweld this system together, but frankly I
know nothing about this process, and the more I read the more
confused I become, and the more it seems the only way I can do this
is by investing some very heavy-duty dollars (special molds, ignitors, etc).
I'm really in WAY over my head, I'm not really mechanically-inclined
and would appreciate any help I can get here by those who understand
such things. I'm afraid that translating theory into practice is not
something I'm comfortable with, alas!
Thanks in advance.
Cheers,
Peter,
W2IRT
------------------------------
Message: 6
Date: Mon, 11 Sep 2006 06:46:13 -0000
From: "Marc Wullaert ON4MA" <marc.wullaert3@pandora.be>
Subject: [TowerTalk] f12- magnum 240N
To: <towertalk@contesting.com>
Message-ID: <000901c6d56e$0b2e4b60$6401a8c0@amd3000>
Content-Type: text/plain; charset=iso-8859-1
I'm starting to build my 6 years old F12 magnum 240H/N who was still in the
box now.
It will be replacing my cushcraft 40cd2 shorty forty who is tranferred to
another tower !
Any pro/con on this antenna ? Tuning of this antenna , some needed
modifications ?
It will be up at 29 m ,4 meters lower will be my C31XR !!
Marc ON4MA
on4ma@pandora.be
pictures : http://users.telenet.be/on4ma/OT5G.html
--
No virus found in this outgoing message.
Checked by AVG Free Edition.
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------------------------------
Message: 7
Date: Mon, 11 Sep 2006 01:58:47 -0500
From: "Mac McCullough" <w5mc@austin.rr.com>
Subject: [TowerTalk] 90' sky needel
To: <Towertalk@contesting.com>
Message-ID: <0f1c01c6d56f$bab15db0$6402a8c0@MacOffice>
Content-Type: text/plain; charset="Windows-1252"
Well thank you all for the past information and finally verifying the proper
cable wrapping of my more vintage 90' model... vs. the later models ... now
however im needing or wanting to restring/ replace the 3 lifting cables, the
main one and the 2 shorter ones that pull up and or down the sections 4 and
6 and as we know the main lift cable working from section 10 lifts up
section 8.. I'd like to find out the exact cable lengths if any of you
know these and then I will either buy them from a supplier or else have them
fabricated here locally by a wire rope shop .. but im wanting to try and
have the cables on hand so that I can perform this exchange while I have the
crane here one time, rather than one time to lift out sections 4 and 6 to
retrieve those cables then section 8 so I can restring it as well, the
intent is to save one extra crane trip and it's associated costing if I can
, but I feel like it would be the prudent thing to do before I place this
tower into long
term expected service ... all help will be greatly welcomed .. thanx
mac/mc w5mc
Located 46 miles due North of the Alamo, and 121 miles due South of the
Western White House. see my website at www.collinsandharrisradios.com
------------------------------
Message: 8
Date: Mon, 11 Sep 2006 09:27:40 -0400
From: "Doug Rehman" <rehman@surveil.com>
Subject: Re: [TowerTalk] 90' sky needel
To: <Towertalk@contesting.com>
Message-ID: <036c01c6d5a6$10643d50$a701a8c0@office>
Content-Type: text/plain; charset="us-ascii"
You might consider buying your own equipment and supplies to make the cables
up on site. McMaster-Carr and other industrial suppliers carry everything
you need. (Make sure you buy the proper size crimps rated for lifting. Also
make sure you buy the right flavor of wire rope.)
You'll need to buy a decent quality wire rope cutter, otherwise it's almost
impossible to get the cut end into the crimp twice (for making the loop at
the cable end). A 28"-36" wire rope cutter works fine for me.
If you follow the simple directions, you'll get a perfect crimp every time.
If you're paranoid like me, double up on the crimps (two crimps on each end)
and you've got twice the holding strength. The Nicopress tool comes with a
jig that allows you to check that your crimping is adequate.
Once you get the hang of it, you can make a cable in just a couple of
minutes.
A spool of wire rope, a wire rope cutter, a Nicopress tool, and Nicopress
crimps cost me about the same as buying the replacement cables
pre-fabricated.
Doug
K4DDR
------------------------------
Message: 9
Date: Mon, 11 Sep 2006 13:46:38 +0000
From: kb9cry@comcast.net (Phil Camera)
Subject: [TowerTalk] Grounding Help
To: TowerTalk@contesting.com
Message-ID:
<091120061346.11008.450568BE00006BB500002B002209229927979D0CC70D05@comcast.n
et>
Content-Type: text/plain
I'll intersperse my comments within snippets of the original post.
I'm hoping to get some wire and ground rods down within the next
couple of weeks but I'm not sure what type of wire specifically I
should be using.
I use #4 bare solid. Larger is OK but don't use stranded.
I'm going to encircle 3 sides of the house (4th
side is a long driveway),
Yay!
and a small circle around the base of my
70' crank up tower with each of the 3 legs connected to a ground rod
and in a circle,
Nope. No need to encircle the tower legs' ground rods, the tower itself
will do the job of distributing the energy amongst the ground radials. But
you need min. of 50 to max of 75 ft. of ground radials connected to each leg
with rods every 2X rod height. Read the Polyphaser technical articles for
more discussion. Do what they recommend; don't skimp, do it right.
which in turn will be connected to the larger length
of wire around the house.
Double Yah!!
go around the house and tie into the service ground, it looks like
I need about 100-150' of wire (I haven't measured exactly yet, but
it's close to that).
Triple Yah. Where your cables enter into the house will be another ground
rod (or more if needed) which will be your SPG. To this you connect all the
grounds from all your lightning arrestors, which are on every cable going
into the shack, as well as a ground wire coming out of the shack to which
all your shack equipment grounds are connected. Very simple actually but
you need to do everything listed for a properly designed system which will
work as advertised.
Couple of questions:
1) Should I also run additional "radials" emanating from this
arrangement, out into the back yard, or does that make a significant
difference?
See tower leg ground radials discussion above. One can never be
overgrounded but there is a point of diminishing returns.
2) What gauge and type of wire should be used for this project? In
what I've read, I've seen many different opinions. 6 solid, 4 solid,
10 stranded, etc? And I'm guessing this will obviously need to be
bare copper, not insulated!
#4 bare solid or larger.
My electrician is clueless about this
kind of grounding, of course -- he thinks I'm crazy, believing one or
two ground rods bound to AC ground are all I need!
He only knows the NEC safety electrical ground. It's not his fault.
a
way to get 'em much deeper than that unless I hire a contractor,
something that's not really in the budget at this point if not 100%
necessary.
Mine are about that depth also. The recommended depth is about 12 inches
though.
4) Where can I buy the proper stainless steel hardware to take a
copper strap from a tower leg (and for that matter, a good place for
copper strapping nowadays!), then bind it to a 5/8" ground rod?
Polyphaser, ICE, Harger
5) I'd really like to Cadweld this system together, but frankly I
know nothing about this process, and the more I read the more
confused I become, and the more it seems the only way I can do this
is by investing some very heavy-duty dollars (special molds, ignitors, etc).
Erico makes CadWeld OneShots which is what I use (also available from RF
Connection) and Harger makes UniShots which are pretty much the same thing.
Here's some webpages with pictures.
http://www.k2ut.org/cadweld.htm
http://www.therfc.com/cadweld.htm
http://www.paigewire.com/DWG/CadweldInstallationInstructions.pdf#search=%22c
adweld%20one%20shot%20%22
I'm really in WAY over my head, I'm not really mechanically-inclined
No you're not. You've got the basic understanding down pat. It's not that
hard.
Phil KB9CRY
------------------------------
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