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Today's Topics:
1. Re: Grounding System Question (john@kk9a.com)
2. FW: [tdxs-list] HLA300 linear amp (Matt)
3. FW: [tdxs-list] HLA300 linear amp (Matt)
4. FW: FW: Force 12 Delta 240 2 Elem 40M Yagi (Matt)
5. Re: TowerTalk] Force 12 Delta 240 2 Elem 40M Yagi (john@kk9a.com)
6. Re: Grounding System Question (Steve Gorecki)
7. Re: WARC-7 - Force 12 (chetmoore)
----------------------------------------------------------------------
Message: 1
Date: Tue, 15 Apr 2014 22:32:16 -0400
From: <john@kk9a.com>
To: <towertalk@contesting.com>
Cc: dxdx@optonline.net
Subject: Re: [TowerTalk] Grounding System Question
Message-ID: <000201cf591c$15886390$40992ab0$@com>
Content-Type: text/plain; charset="us-ascii"
No the ground rods do not need be completely around the tower. I seem to
recall the Polyphaser catalog showing ground rod lines that do not cover
360
degrees around the tower. Look at their catalog for suggestions on ground
rod placement. Mine go out 50-60 feet from the tower base. Six ground
rods
is not many for a tower.
John KK9A
[TowerTalk] Grounding System Question
from [Tony] [Permanent Link][Original]
To: towertalk@contesting.com
Subject: [TowerTalk] Grounding System Question
From: Tony <dxdx@optonline.net>
Date: Mon, 14 Apr 2014 20:48:11 -0400
All:
My crank-up tower is located a few feet from the house and each leg is
attached to a ground rod that's about a foot or so away from the
foundation.
I'd like to add 3 more rods in a radial pattern to help "divert" a
potential
lightning strike away from the house. The grounds can't be positioned 360
degrees around the tower due to it's close proximity to the house so I'm
not
sure how critical that is.
Any suggestions on this subject as well as rod spacing and copper strap
size
would be appreciated.
Thanks
Tony
------------------------------
Message: 2
Date: Tue, 15 Apr 2014 23:20:21 -0500
From: "Matt" <maflukey@gmail.com>
To: <towertalk@contesting.com>
Subject: [TowerTalk] FW: [tdxs-list] HLA300 linear amp
Message-ID: <04a201cf592b$2f0fbca0$8d2f35e0$@gmail.com>
Content-Type: text/plain; charset="utf-8"
I ran a 1.2kW homebrew SS amp in my mobile for about 10 years using pairs
of group 24 automotive batteries connected in parallel. The following
calculations proved out more-or-less correct though some measurements that
I made:
Peak input power = output / efficiency = ~1200/.6 = ~2000w peak
For compressed SSB, average input power = input power x duty cycle = ~2000
x .40 = 800w average
Automotive batteries are typically rated 60-120 amp hrs. The average
total stored energy is about 1,000 watt-hrs per battery BUT voltage will
fall off as a function of charge level and discharge current rate. A
point is reached where amplifier output will become non-linear well before
the battery is fully discharged. Therefore, the full storage capacity of
the battery(s) is not be realistically usable. Full discharge cycling of
a lead acid batteries also significantly shortens the life of the battery
anyway.
Back to the math? at 30-40 amp average discharge rate, typical battery
voltage will fall off according to state-of-charge as follows:
100% charge ? 11.7v
70% charge ? 11.5v
40% charge ? 11.0v
30% charge ? 10.7v
20% charge ? 10.3v
10% charge - <10v
Remember that these are voltages under 30-40 amps average load ? not while
idling.
Considering that the amp pulled about 160A of current on voice peaks, I
would typically only run the batteries down to around 40% (11v nominal
during transmit) before recharging. This would give me about an hour of
useable transmit time as follows:
2 x 1000W-hrs x 40% / 800W = ~60 minutes of transmit time.
If you are looking at using a 300w output amp with a single auto battery,
then you should see about 2hrs of useable transmit time per charge.
P.S. When looking for batteries ? go for the largest case size per
cold-crank-amp rating. My experience is that they will generally give you
the longest service life. I have found that group 27?s are the best if
you can find them at a reasonable cost, group 24?s are typically the best
in $ per service life. Avoid the newer small case batteries. I have
personally found that ?deep cycle? batteries were not worth the premium
cost?.
Hope this is info is useful to you & have fun!
73
Matt
KM5VI
From: Steve Smothers [mailto:cougar70@earthlink.net]
Sent: Saturday, April 12, 2014 6:53 PM
To: James Carmody; tdxs-list
Subject: Re: [tdxs-list] HLA300 linear amp
Spec says you'll need a supply of at least 40 amps at 12-14v DC. I would
think almost any auto battery would be capable of that, but for how long
is the question. When I put a new one on for the US Islands Awards
program, I used a regular deep cycle marine battery and operated my 100w
rig for a few hours with no problem.
Steve -
W9DX
.-----Original Message-----
From: James Carmody
Sent: Apr 12, 2014 6:43 PM
To: tdxs-list
Subject: [tdxs-list] HLA300 linear amp
Anybody have one? I just got one very cheap on eBay but have not fired it
up yet. Debating on whether to power it with a small auto battery (higher
current than deep cycle) trickle charged. Tuner?
Jim NN5O
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Message: 3
Date: Tue, 15 Apr 2014 23:29:32 -0500
From: "Matt" <maflukey@gmail.com>
To: <towertalk@contesting.com>
Subject: [TowerTalk] FW: [tdxs-list] HLA300 linear amp
Message-ID: <06f101cf592c$7730e580$6592b080$@gmail.com>
Content-Type: text/plain; charset="utf-8"
Debating on whether to power it with a small auto battery (higher
current than deep cycle) trickle charged.
P.S. A 10 amp charger into your battery(s) should keep up with the load
even in a run-frequency contest situation on phone. Double it for RTTY.
Beware to read the fine print on continuous duty cycle rating before
buying a charger these days?
Matt
KM5VI
From: Matt [mailto:maflukey@gmail.com]
Sent: Tuesday, April 15, 2014 11:20 PM
To: towertalk@contesting.com
Subject: FW: [tdxs-list] HLA300 linear amp
I ran a 1.2kW homebrew SS amp in my mobile for about 10 years using pairs
of group 24 automotive batteries connected in parallel. The following
calculations proved out more-or-less correct though some measurements that
I made:
Peak input power = output / efficiency = ~1200/.6 = ~2000w peak
For compressed SSB, average input power = input power x duty cycle = ~2000
x .40 = 800w average
Automotive batteries are typically rated 60-120 amp hrs. The average
total stored energy is about 1,000 watt-hrs per battery BUT voltage will
fall off as a function of charge level and discharge current rate. A
point is reached where amplifier output will become non-linear well before
the battery is fully discharged. Therefore, the full storage capacity of
the battery(s) is not be realistically usable. Full discharge cycling of
a lead acid batteries also significantly shortens the life of the battery
anyway.
Back to the math? at 30-40 amp average discharge rate, typical battery
voltage will fall off according to state-of-charge as follows:
100% charge ? 11.7v
70% charge ? 11.5v
40% charge ? 11.0v
30% charge ? 10.7v
20% charge ? 10.3v
10% charge - <10v
Remember that these are voltages under 30-40 amps average load ? not while
idling.
Considering that the amp pulled about 160A of current on voice peaks, I
would typically only run the batteries down to around 40% (11v nominal
during transmit) before recharging. This would give me about an hour of
useable transmit time as follows:
2 x 1000W-hrs x 40% / 800W = ~60 minutes of transmit time.
If you are looking at using a 300w output amp with a single auto battery,
then you should see about 2hrs of useable transmit time per charge.
P.S. When looking for batteries ? go for the largest case size per
cold-crank-amp rating. My experience is that they will generally give you
the longest service life. I have found that group 27?s are the best if
you can find them at a reasonable cost, group 24?s are typically the best
in $ per service life. Avoid the newer small case batteries. I have
personally found that ?deep cycle? batteries were not worth the premium
cost?.
Hope this is info is useful to you & have fun!
73
Matt
KM5VI
From: Steve Smothers [mailto:cougar70@earthlink.net]
Sent: Saturday, April 12, 2014 6:53 PM
To: James Carmody; tdxs-list
Subject: Re: [tdxs-list] HLA300 linear amp
Spec says you'll need a supply of at least 40 amps at 12-14v DC. I would
think almost any auto battery would be capable of that, but for how long
is the question. When I put a new one on for the US Islands Awards
program, I used a regular deep cycle marine battery and operated my 100w
rig for a few hours with no problem.
Steve -
W9DX
.-----Original Message-----
From: James Carmody
Sent: Apr 12, 2014 6:43 PM
To: tdxs-list
Subject: [tdxs-list] HLA300 linear amp
Anybody have one? I just got one very cheap on eBay but have not fired it
up yet. Debating on whether to power it with a small auto battery (higher
current than deep cycle) trickle charged. Tuner?
Jim NN5O
-------------- next part --------------
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------------------------------
Message: 4
Date: Wed, 16 Apr 2014 00:23:02 -0500
From: "Matt" <maflukey@gmail.com>
To: <towertalk@contesting.com>
Subject: [TowerTalk] FW: FW: Force 12 Delta 240 2 Elem 40M Yagi
Message-ID: <0b4501cf5933$f0908140$d1b183c0$@gmail.com>
Content-Type: text/plain; charset="us-ascii"
Thanks Grant!
Matt
-----Original Message-----
From: Grant Saviers [mailto:grants2@pacbell.net]
Sent: Tuesday, April 15, 2014 10:04 AM
To: Matt
Subject: Re: [TowerTalk] FW: Force 12 Delta 240 2 Elem 40M Yagi
Matt,
Are you aware of the W6NL Moxon designs? There are 3, two mods of
existing
40m shorty beams and one that is a scratch build. They are in use by big
contestors - eg. K3LR and 8P5A. I've built two, one for myself and one
for
K6KR and now have a second built by K7ZSD for stack , these are the 110mph
scratch build designs.
Anyway, they perform extremely well and avoid the mechanical and
gain/bandwidth/FB problems of other "shorty 40's".
You can find more info in the Dayton archives in the section moderated by
K3LR, or I can send some you some pdfs.
Grant KZ1W
------------------------------
Message: 5
Date: Wed, 16 Apr 2014 09:03:42 -0400
From: john@kk9a.com
To: towertalk@contesting.com
Subject: Re: [TowerTalk] TowerTalk] Force 12 Delta 240 2 Elem 40M Yagi
Message-ID: <3da7f4fe42830ab966827598753739b5.squirrel@www11.qth.com>
Content-Type: text/plain;charset=iso-8859-1
This is a great design, however with the 19 or so foot T sections it is
not a small antenna. I would not consider them to be a shorty forty.
John KK9A
-----Original Message-----
From: Grant Saviers [mailto:grants2@pacbell.net]
Sent: Tuesday, April 15, 2014 10:04 AM
To: Matt
Subject: Re: [TowerTalk] FW: Force 12 Delta 240 2 Elem 40M Yagi
Matt,
Are you aware of the W6NL Moxon designs? There are 3, two mods of
existing
40m shorty beams and one that is a scratch build. They are in use by big
contestors - eg. K3LR and 8P5A. I've built two, one for myself and one
for
K6KR and now have a second built by K7ZSD for stack , these are the 110mph
scratch build designs.
Anyway, they perform extremely well and avoid the mechanical and
gain/bandwidth/FB problems of other "shorty 40's".
You can find more info in the Dayton archives in the section moderated by
K3LR, or I can send some you some pdfs.
Grant KZ1W
------------------------------
Message: 6
Date: Tue, 15 Apr 2014 11:52:52 -0400
From: Steve Gorecki <ve3cwj@gmail.com>
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Grounding System Question
Message-ID:
<CAEYPScCh-9F=_b6XVqhBSYFpwkVarBD32S+Z5jdoRfL+E5Gh+g@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8
Tony, I would suggest adding even more rods if possible, like at least 6.
I
used 4 foot 1/2" copper pipe spaced at 8 foot intervals (usual twice the
rod length rule of thumb). I made home-made clamps out of 3/4 inch pipe,
slit into two halves, and clamped the 2" copper strapping 1/2 way around
each pipe, then screwed it all together with SS machine screws (should the
worm clamps let go). The 2" strapping runs between about 9 rods all
together. Be sure to use copper to copper anti oxidant on each and every
connection. Do NOT use Noalox or any other brand of aluminum to copper
compound for pure copper to copper connections. You must use compound
designed for copper to copper only, if you want it to last. I'm not sure
of
the thickness of my 2" strapping, but recall it comes out to about a #3
AWG
equivalent in cross section area. I had bought a 4x8 foot sheet of copper
flashing at a local roofing company, and had them shear it to 2" widths.
So, determine the length of the ground rod, double it, and install them
that distance from the original rods. If using 6 foot rods, go 12 feet
maximum. Then go another 12 feet and put in a second one on each leg. Same
for 4 foot rods, go 8 feet between. The more the better.
Hope that helps with some ideas at least.
Steve
VE3CWJ/ VE3RX
------------------------------
Message: 7
Date: Tue, 15 Apr 2014 16:27:52 -0400
From: "chetmoore" <chetmoore@cox.net>
To: "'Wayne Kline'" <w3ea@hotmail.com>, <towertalk@contesting.com>
Subject: Re: [TowerTalk] WARC-7 - Force 12
Message-ID: <054201cf58e9$2d420780$87c61680$@net>
Content-Type: text/plain; charset="us-ascii"
Hi wayne.
My warc 7 has been up about 7 years. It was probably one of the last ones
made by
N6BT before he sold the company to some one in texas. This antenna
performs as advertised
And has been trouble free.
Hope you can get yours back in working order
73
Chet N4FX, KP4EAJ, VQ9XX, ZD8W, N6ZO, N6ZO/6Y5, N6ZO/HH9, KG4ZO, KL7AIZ
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of
Wayne
Kline
Sent: Tuesday, April 15, 2014 3:17 PM
To: towertalk@contesting.com
Subject: [TowerTalk] WARC-7 - Force 12
Hello Fellow TT'ers
After Hurricane Sandy tore through eastern US. I picked up a pile of
aluminum from the carnage.
one pile was remnants of a F-12 C3 ( WOW) it was TOAST . The other
pieces
of a F-12 WARC-7
I was able to piece a boom together but the few straight piece left
gave
me not much of a clue as to the original antennas configuration. So
B-4
I make Tomato stakes out of it.
Dose any body HAVE a copy of the old F-12 WARC -7 manual or just the
over view page.
with the dimensions on ! I'll gladly pay for copy and postage or scan an
image to me at W3EA@hotmail.com
Thanks Wayne W3EA
PS my interest in the WARC bands was sparked by the W1AW Centennial ...
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End of TowerTalk Digest, Vol 136, Issue 51
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