Why use a relay, you don't need it. Run all three bands from a common
feedpoint, with appropriate radials. There is no need for a relay. When you
pick
40 meters, it will work on 40, and so on! Willy K3VW
In a message dated 9/29/2009 3:01:50 P.M. Eastern Daylight Time,
topband-request@contesting.com writes:
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than "Re: Contents of Topband digest..."
Today's Topics:
1. relay-switched inverted L for 40/80/160 (Jim Meehan)
2. Re: Ground Radials and an inv-L antenna (w8av)
3. Marconi: out, Inverted L: up at WY7I (WY7I)
4. Re: relay-switched inverted L for 40/80/160 (Rick Karlquist)
5. Re: Marconi: out, Inverted L: up at WY7I (Wes Attaway (N5WA))
6. Here's one for ya (WY7I)
7. Results- 2008 Stew Perry TopBand Extravaganza (Lew Sayre)
8. Re: relay-switched inverted L for 40/80/160 (DAVID CUTHBERT)
----------------------------------------------------------------------
Message: 1
Date: Mon, 28 Sep 2009 12:22:53 -0700
From: Jim Meehan <jmeehan@vpizza.org>
Subject: Topband: relay-switched inverted L for 40/80/160
To: topband@contesting.com
Message-ID:
<f694cf360909281222v79e92cffpec400917f8ac6ed8@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
I've mulling over a tree-supported wire inverted L for 40/80/160 meters.
The vertical section would be supported by a high branch on a ~55' Monterey
pine not too far from my house, and the horizontal section from there to
another tree. Lots of radials of various lengths should be no problem.
Originally I had thought to use traps to achieve multi-band operation, but
then I started wondering about using relays to simply switch out the
various
segments. If I used two-conductor speaker wire or something similar as the
radiator, I think the same wire could also carry DC to operate the relays.
I'd use SPDT normally-closed relays. For operation on 160, no DC is
applied
-- both relays are closed, and the entire length of the inverted L is
active. For operation on 80, +12V is applied, opening the "far" relay,
cutting off both conductors of the 160 segment. For operation on 40, -12V
is a applied, opening the "near" relay. This would be for 100 watts only,
so I don't think I'd need anything too exotic for components.
My hope is that it would have wider bandwidth than traps would allow, and
be
easier to construct and tune.
Am I missing anything obvious? I did a little Googling and didn't find any
designs like this.
Also wondering about the bandwidth/hassle/cost tradeoff of using copper
pipe
or aluminum tubing for the vertical section. In this case, I'd run a wire
up the center of the pipe to use as the 2nd conductor for the relay
switching. I would put the pipe next to the tree, supporting it with some
kind of standoffs attached to the trunk of the Monterey pine. Can I get
the
pipe far enough from the tree trunk to minimize interaction, but still
close
enough for standoffs to be practical? Is the bandwidth gain of pipe over
wire enough to make this worthwhile?
Thanks for your consideration,
Jim Meehan, W6XE
Oakland, CA
------------------------------
Message: 2
Date: Mon, 28 Sep 2009 15:24:30 -0400
From: w8av <w8av@aol.com>
Subject: Re: Topband: Ground Radials and an inv-L antenna
To: "Dennis Peterson" <dennisissure@comporium.net>,
topband@contesting.com
Message-ID: <432bc5c4.4528.4505.8713.e3b920f02943@aol.com>
Content-Type: TEXT/plain; charset=us-ascii
Dennis:
You have not reached a point of diminishing returns here. Although you
see no virtual change in the antenna VSWR, the radiation efficiency of the
antenna system improves every time you add additional radials under the ant
enna. There is published data in the Proceedings of the IRE that show that
once you reach 120 radials you see no additional improvements to the
efficiency of the antenna by adding more radials. With regard to length, the
magic cut-off number for no improvement to radiation efficiency is 0.4
wavelengths. That is why when I worked in the broadcast industry, we always
installed 120 radials of at least a quarter wavelength long under all AM
broadcast towers.
You have reached a point where the transmitter is happy with the antenna
match but you can improve the antenna's signal radiating efficiency by
adding still more radials under the antenna. You are trying to reduce the
ground losses in the near field of the antenna with the ground system and when
you finally reach 120 1/4 wavelength radials, the antenna will be about as
good as it can be. You should also not see any VSWR change by adding the
additional radials.
If you can't get to a 1/4 wavelength in all directions, you can add more
radials in the shortened areas to help improve the radiation efficiency in
those directions where the ground system is shortened. If you can't get 120
radials down, put as many down as you physically can and make them as long
as you can.
73.................de Goose, W8AV
------------------------------
Message: 3
Date: Mon, 28 Sep 2009 15:11:47 -0600
From: WY7I <WY7I@EARTHLINK.NET>
Subject: Topband: Marconi: out, Inverted L: up at WY7I
To: topband@contesting.com
Message-ID: <4AC12693.7010601@EARTHLINK.NET>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Hi all,
I wanted to bring you up to date on my 160m antenna situation.
I wanted at first to put up a T top Marconi, and I did, but then we all
decided it needed to be longer along the top wire. I took it down and
figured I had to add 85 feet total. While I was at it, I measured the
vertical wire and it turned out to be only 44 feet long. I decided the
tree was too low and abandoned the Marconi idea. I had already laid down
32 100-ft. radials under the center point...
So I went back to the Inverted-L idea. I ran a #12 stranded wire up the
side of the tower, stand-offs were about 4' out. So that's about 68'
vertical and then 135-68=67' horizontal, the total length is 135'. I
wanted it to be resonant at 1.800-1.850, hopefully. Then I had to move
all the #@$%^ radials over to underneath the tower. I added an RFC and
two spark-gap modules from the vertical wire to ground. The radial plate
is NOT grounded to earth. I hooked up a short length of LMR-400 from the
antenna to the antenna switch; total coax length out to the antenna is
about 265 feet.
Came inside the shack checked the SWR curve....it's very nice, between
1.1:1 and 1.3:1 for the frequencies I mentioned. Seems to be pretty
broad, at least enough for any 160m CW.
I only have one question (other than 'how does it work on DX?' which
will be answered in the next few nights!) and that question is, do I
need a 1:1 unun to isolate the feedline from the antenna to possibly
prevent TVI/RFI or other overloads? The 900' beverage takes off about
25' from the base of the tower. I think a couple of the radials wound up
going under the beverage, which is up at 7' off the ground. I plan to
hook up an ICE RF-limiter before going QRO with this system.
Appreciate all your help and thoughts!
Regards,
Paul
WY7I
Chromo, CO
DM67PD
------------------------------
Message: 4
Date: Mon, 28 Sep 2009 17:00:01 -0700 (PDT)
From: "Rick Karlquist" <richard@karlquist.com>
Subject: Re: Topband: relay-switched inverted L for 40/80/160
To: "Jim Meehan" <jmeehan@vpizza.org>
Cc: topband@contesting.com
Message-ID:
<305fc7f9af8e72feeb95d4b1df5a5795.squirrel@webmail.sonic.net>
Content-Type: text/plain;charset=iso-8859-1
Jim Meehan wrote:
> then I started wondering about using relays to simply switch out the
> various
> segments. If I used two-conductor speaker wire or something similar as
> the
> radiator, I think the same wire could also carry DC to operate the
relays.
> I'd use SPDT normally-closed relays. For operation on 160, no DC is
> applied
> -- both relays are closed, and the entire length of the inverted L is
> active. For operation on 80, +12V is applied, opening the "far" relay,
> and tune.
> Am I missing anything obvious? I did a little Googling and didn't find
> any
> designs like this.
>> Jim Meehan, W6XE
> Oakland, CA
I have posted many times on this subject to this reflector.
I used a 40/80/160 vertical switched by relays for many years.
The relays were vacuum relays that never lasted more than a
year before needing replacement. When working, the vertical
was great, and the bandwidth was definitely better than with
traps. I recently decided to try modified open frame relays
as shown in my Hints and Kinks article in May 2009 QST. You
can definitely send DC through the lower relays to get to the
upper relays. I use a string of ten 1-meg carbon comp resistors
in series across the relays so that static voltage cannot build
up across the contacts when they are open. The relays should
be going into service late this year, so we will see how they
hold up.
Rick N6RK
------------------------------
Message: 5
Date: Mon, 28 Sep 2009 19:23:49 -0500
From: "Wes Attaway \(N5WA\)" <wesattaway@bellsouth.net>
Subject: Re: Topband: Marconi: out, Inverted L: up at WY7I
To: <WY7I@EARTHLINK.NET>, <topband@contesting.com>
Message-ID: <2D558F0498F44EA2971470194EEE55E3@OFFICE>
Content-Type: text/plain; charset="us-ascii"
I think it is broad because of the proximity to your tower and beams. The
whole "mass" of stuff is coupled together. Relax and enjoy it.
------------------ Wes Attaway (N5WA) ------------------
1138 Waters Edge Circle - Shreveport, LA 71106
318-797-4972 (office) - 318-393-3289 (cell)
Computer Consulting and Forensics
-------------- EnCase Certified Examiner ---------------
-----Original Message-----
From: topband-bounces@contesting.com
[mailto:topband-bounces@contesting.com]
On Behalf Of WY7I
Sent: Monday, September 28, 2009 4:12 PM
To: topband@contesting.com
Subject: Topband: Marconi: out, Inverted L: up at WY7I
Hi all,
I wanted to bring you up to date on my 160m antenna situation.
I wanted at first to put up a T top Marconi, and I did, but then we all
decided it needed to be longer along the top wire. I took it down and
figured I had to add 85 feet total. While I was at it, I measured the
vertical wire and it turned out to be only 44 feet long. I decided the
tree was too low and abandoned the Marconi idea. I had already laid down
32 100-ft. radials under the center point...
So I went back to the Inverted-L idea. I ran a #12 stranded wire up the
side of the tower, stand-offs were about 4' out. So that's about 68'
vertical and then 135-68=67' horizontal, the total length is 135'. I
wanted it to be resonant at 1.800-1.850, hopefully. Then I had to move
all the #@$%^ radials over to underneath the tower. I added an RFC and
two spark-gap modules from the vertical wire to ground. The radial plate
is NOT grounded to earth. I hooked up a short length of LMR-400 from the
antenna to the antenna switch; total coax length out to the antenna is
about 265 feet.
Came inside the shack checked the SWR curve....it's very nice, between
1.1:1 and 1.3:1 for the frequencies I mentioned. Seems to be pretty
broad, at least enough for any 160m CW.
I only have one question (other than 'how does it work on DX?' which
will be answered in the next few nights!) and that question is, do I
need a 1:1 unun to isolate the feedline from the antenna to possibly
prevent TVI/RFI or other overloads? The 900' beverage takes off about
25' from the base of the tower. I think a couple of the radials wound up
going under the beverage, which is up at 7' off the ground. I plan to
hook up an ICE RF-limiter before going QRO with this system.
Appreciate all your help and thoughts!
Regards,
Paul
WY7I
Chromo, CO
DM67PD
_______________________________________________
Topband mailing list
Topband@contesting.com
http://lists.contesting.com/mailman/listinfo/topband
------------------------------
Message: 6
Date: Mon, 28 Sep 2009 20:00:26 -0600
From: WY7I <WY7I@EARTHLINK.NET>
Subject: Topband: Here's one for ya
To: topband@contesting.com
Message-ID: <4AC16A3A.1060009@EARTHLINK.NET>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
If I xmt on the inverted L and receive on it, the SWR is 1:1.
If I use the beverage to recieve, then the SWR is too high.
Coupling?
P.
------------------------------
Message: 7
Date: Mon, 28 Sep 2009 23:19:56 -0700
From: Lew Sayre <w7ew@arrl.net>
Subject: Topband: Results- 2008 Stew Perry TopBand Extravaganza
To: cq-contest@contesting.com
Cc: topband@contesting.com
Message-ID:
<a18017910909282319o407280d0rcceec996de49937f@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
Ladies, Gentlemen and others,
The Boring Amateur Radio Club is pleased to release the results of
the 13th running of the Stew Perry TopBand DX Challenge. The log checking
committee worked long and hard to bring you these results in such fine
style. Please read carefully the overall results and understand well what
miracles some of the plaque winners accomplished. The results live at
http://jzap.com/k7rat/stew.html .
The official 14th Edition of The Stew Perry TopBand DX Challenge will
be December 26-27, 2009. Seems like a long time in the future for some
good
grid grabbing action, yes? The Stimulus Committee of The Boring Amateur
Radio Club has heard you and promulgated an official "warm-up" for The Stew
Perry Contest for October 17-18, 2009. Same rules-same idea but the
warm-up
will not have the plaques. It will have serious 160M cw flying all about
the
globe with new and improved stations and operators. You will be satisfied
that the secret improvements you've made during the summer will have all
the
bugs worked out and that only silly Christmas parties and libations could
slow you down for the Real Stew.
Speaking of plaques, The Plaqueing Committee of the Boring Amateur
Radio Club will roust the local plaque maker to have the 2008 plaques off
to the deserving shortly after Nov 1. The Boring Amateur Radio Club is
slightly different from the other excellent 160M contests sponsored by
National Organizations and fascinating radio magazines. We believe that
the
engaged radio combatants should define what qualities a plaque winner
should
possess and that if the category passes the family hour test then it should
be open to any who wish to strive for it. Go back and re-read the list of
plaques that were available for 2008. Note the sponsors. These donors are
the stuff of which radio contesting is made of. You can be a sponsor of
such
a plaque for 2009 by proposing a category for competition and sending
$55.00
to the club. Such proposals should be sent to me at the email address
below. Stalwarts such as KL7RA, VK6VZ, and a host of other listed radio
luminaries have already started their plaqueing process for 2009!
Rumors of solar cycle 24 having peaked last week after 2 simultaneous
sunspots are probably wrong. The Boring Amateur Radio Club had no part in
naming this upcoming solar cycle period "The Boring Minimum" even though
solar cycle minimums seem to be good for 160M propagation. It is just like
1928, in more ways than one, all over again.
There will be more updates as we approach these events. Thanks again
to the fearless Club Logcheckers and IT department!
73 and I remain,
Lew W7EW/W7AT
The Boring Amateur Radio Club Plaque Proliferator
w7ew@arrl.net
------------------------------
Message: 8
Date: Tue, 29 Sep 2009 06:35:54 -0600
From: DAVID CUTHBERT <telegrapher9@gmail.com>
Subject: Re: Topband: relay-switched inverted L for 40/80/160
To: Jim Meehan <jmeehan@vpizza.org>
Cc: topband@contesting.com
Message-ID:
<bd146ab90909290535m668f2770tc57254df3a7fb156@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
Jim,
this will work. If you are going to put the wire lengths in series (33',
33', and 66') you will need a way to decouple the the relay coil wires
between the wire sections; two relays. The decoupling can be done with
parallel tuned LC circuits. As these are 'traps', simply dispense with the
relays and use the traps to make your three band antenna.
Dave WX7G
On Mon, Sep 28, 2009 at 1:22 PM, Jim Meehan <jmeehan@vpizza.org> wrote:
> I've mulling over a tree-supported wire inverted L for 40/80/160 meters.
> The vertical section would be supported by a high branch on a ~55'
Monterey
> pine not too far from my house, and the horizontal section from there to
> another tree. Lots of radials of various lengths should be no problem.
>
> Originally I had thought to use traps to achieve multi-band operation,
but
> then I started wondering about using relays to simply switch out the
> various
> segments. If I used two-conductor speaker wire or something similar as
the
> radiator, I think the same wire could also carry DC to operate the
relays.
> I'd use SPDT normally-closed relays. For operation on 160, no DC is
> applied
> -- both relays are closed, and the entire length of the inverted L is
> active. For operation on 80, +12V is applied, opening the "far" relay,
> cutting off both conductors of the 160 segment. For operation on 40,
-12V
> is a applied, opening the "near" relay. This would be for 100 watts
only,
> so I don't think I'd need anything too exotic for components.
>
> My hope is that it would have wider bandwidth than traps would allow, and
> be
> easier to construct and tune.
>
> Am I missing anything obvious? I did a little Googling and didn't find
any
> designs like this.
>
> Also wondering about the bandwidth/hassle/cost tradeoff of using copper
> pipe
> or aluminum tubing for the vertical section. In this case, I'd run a
wire
> up the center of the pipe to use as the 2nd conductor for the relay
> switching. I would put the pipe next to the tree, supporting it with
some
> kind of standoffs attached to the trunk of the Monterey pine. Can I get
> the
> pipe far enough from the tree trunk to minimize interaction, but still
> close
> enough for standoffs to be practical? Is the bandwidth gain of pipe over
> wire enough to make this worthwhile?
>
> Thanks for your consideration,
>
> Jim Meehan, W6XE
> Oakland, CA
> _______________________________________________
> Topband mailing list
> Topband@contesting.com
> http://lists.contesting.com/mailman/listinfo/topband
>
------------------------------
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End of Topband Digest, Vol 81, Issue 32
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