Dave,
Another possibility for 160 -- Don't know to what extent/effort you want to
go to get on 160, but here is an easy way, although, a bit of a compromise.
Simply open the loop at one of the 80 meter voltage loops (also a current
node). The 80 meter standing wave current distribution /performance will
not change, but it will force the wire to be an off center fed 1/2
wavelength for 160. Although not quite resonant within the 160 meter band,
if you feed it with open wire and run it thru the appropriate matching
network, you should be right.
Quite possibly, if you adjust your overall length you might be able to find
a length that is 1 wl on 80 where you need it and 1/2 wl on 160 close to
where you want to work. Have a look at this in EZNEC to see how it will
work for you in your particular situation. I use this method to run 80 on
my 40 meter delta loop.
It is a lot easier than relays and switches, but Don's good suggestion might
be the preferred solution for you.
GL...Rick -- W5RH
Date: Tue, 20 Feb 2007 23:47:33 -0500
From: "Don Wilhelm" <[EMAIL PROTECTED]>
Subject: RE: [Elecraft] wire antennas
To: "David Wilburn" <[EMAIL PROTECTED]>,
<elecraft@mailman.qth.net>
Message-ID: <[EMAIL PROTECTED]>
Content-Type: text/plain; charset="iso-8859-1"
Dave,
As far as switching your loop to a 160 top loaded vertical, yes you can do
it remotely with relays and a matching network. If your goal is efficiency
on 160 meters, the relay switching os only a small part of the equation -
you must have a good RF ground for the vertical to work against, and that
menas lots of wires in the ground, radiating from the base of the antenna.
Some will tell you tht 120 radials will give optimum performance, but 16 or
more will give great performance as well. If the radials are buried, the
length is not critical, lots of short buried radials will do almost as good
as a moderate number of long ones - see the 160 meter antenna simulation
results that are outlined on L B Cebik's website www.cebik.com. More
information on low band antennas can be found in ON4UN's Low Band DXing
book - there are many possibilities.
For best results, put the 160 meter matching network at the base of the
antenna and match it to your feedline.
Since there are many possibilities, make some decision even though it may be
a compromise and you too can be successful on 'top-band'.
73,
Don W3FPR
> -----Original Message-----
>
> I am very much enjoying reading the discussions on wire antennas. I
> have something I have been trying to figure out how to do for some time,
> and thought this might be a good place to ask.
>
> I have an 80m loop, up about 60 or 70 feet. Currently it is fed with
> 300 ohm line. All I could find at the time, as what I had left in 450
> ohm line (after I helped my elderly neighbor get his antenna back up,
> and gave him some of the ladder line) was not long enough.
> Additionally, I went to the local hamfest this weekend and could not
> find a single vendor selling ladder line, but I digress. I have
> approximately 290 feet of wire in the air in a horizontal, triangular
> configuration, fed with (soon to be) ladder line, a balun (1:1) and then
> coax to the shack. Is it possible to switch this (seems possible from
> what I have read) to a 160m antenna by taking one side to ground at the
> balun and feeding the other side? If this is possible, is there a way
> to do this remotely?
>
> David Wilburn
> [EMAIL PROTECTED]
> K4DGW
>
--
No virus found in this outgoing message.
Checked by AVG Free Edition.
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1:44 PM
------------------------------
Message: 2
Date: Tue, 20 Feb 2007 23:46:42 -0500
From: "Matthew D. Pitts" <[EMAIL PROTECTED]>
Subject: Re: [Elecraft] Custom K2?
To: Bob Nielsen <[EMAIL PROTECTED]>
Cc: Elecraft <elecraft@mailman.qth.net>
Message-ID: <[EMAIL PROTECTED]>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
So tempting... I haven't fiddled with Linux in a few years and might be
able to scrounge up a PC to run it on (I think all I'm missing for a
working system amongst the parts I have is a power supply).
Bob Nielsen wrote:
>
> On Feb 20, 2007, at 3:32 PM, Ian Stirling wrote:
>
>> On Tuesday 20 February 2007 18:19, you wrote:
>>
>>> Rig control software for people who use "real" computers (Fedora Core
>>> here). http://www.hamsoftware.org/ Haven't used it, but saw your
>>> comment and did a quick google. This is the first one I ran across,
>>> may
>>> be others. Are you on Mac or Linux? Because there were quite a few
>>> choices for Mac also.
>>
>> Multiplexing myself between my kubuntu/gnu/linux computer
>> and cooking cream of scallion soup. I've recently switched
>> to kubuntu from FreeBSD 6.1.
>
> There are a lot of good ham apps suitable for use with a K2 that are
> in the repositories for Ubuntu (and I assume kubuntu and xubuntu as
> well; they are all Debian derivatives): hamlib, gmfsk, xlog, tlf, to
> name a few I have used.
>
> 73 - Bob, N7XY
> _______________________________________________
> Elecraft mailing list
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> Subscriber Info (Addr. Change, sub, unsub etc.):
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> Elecraft web page: http://www.elecraft.com
>
------------------------------
Message: 3
Date: Tue, 20 Feb 2007 21:32:55 -0800
From: "Don" <[EMAIL PROTECTED]>
Subject: Re: [Elecraft] wire antennas
To: "David Wilburn" <[EMAIL PROTECTED]>,
<elecraft@mailman.qth.net>
Message-ID: <[EMAIL PROTECTED]>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=response
Have you tried using the antenna on 160 through a tuner just as it is?
Chances are you can match it even on 160M and if you do you will not have to
worry about the ground losses you would have feeding it against ground
(unless using lots of radials).
Don K7FJ
----- Original Message -----
From: "David Wilburn" <[EMAIL PROTECTED]>
To: <elecraft@mailman.qth.net>
Sent: Tuesday, February 20, 2007 8:07 PM
Subject: Re: [Elecraft] wire antennas
>I am very much enjoying reading the discussions on wire antennas. I have
>something I have been trying to figure out how to do for some time, and
>thought this might be a good place to ask.
>
> I have an 80m loop, up about 60 or 70 feet. Currently it is fed with 300
> ohm line. All I could find at the time, as what I had left in 450 ohm
> line (after I helped my elderly neighbor get his antenna back up, and gave
> him some of the ladder line) was not long enough. Additionally, I went to
> the local hamfest this weekend and could not find a single vendor selling
> ladder line, but I digress. I have approximately 290 feet of wire in the
> air in a horizontal, triangular configuration, fed with (soon to be)
> ladder line, a balun (1:1) and then coax to the shack. Is it possible to
> switch this (seems possible from what I have read) to a 160m antenna by
> taking one side to ground at the balun and feeding the other side? If
> this is possible, is there a way to do this remotely?
>
> David Wilburn
> [EMAIL PROTECTED]
> K4DGW
>
>
> _______________________________________________
> Elecraft mailing list
> Post to: Elecraft@mailman.qth.net
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
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> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com
------------------------------
Message: 4
Date: Wed, 21 Feb 2007 05:34:22 -0000
From: "Tierra del Mar Labs" <[EMAIL PROTECTED]>
Subject: [Elecraft] twin lead not just HF
To: <elecraft@mailman.qth.net>
Message-ID: <[EMAIL PROTECTED]>
Content-Type: text/plain; charset="us-ascii"
Aloha to all,
I joined this list a month ago to ask a question about an xv222 that had
a bad crystal. Since then, the most fascinating threads abound here
most, stretching far from Elecraft matters. Cool!
I would like to state that I am no expert to balanced feed lines but
reading here, I must state how forgiving this medium is.
I use twin lead for my arrays, 144 thru 1296, splice this and that,
solder blobs, different wire sizes, whatever. All my micro wave and
vhf/uhf stuff comes over 400 feet back to the house at 28 and 14 MHz
IF's, simple 600 Ohm tiwn lead built open air style on short utility
poles. This stuff is so forgiving and to the uhf and up enthusiast, Much
quieter than coax.
Kind'a like the Bi-Polar and the FET in the first days of the
transistor....who made the mistake of going the Bi-Polar way anyway, we
must have lost 20 years of technology to this.
I'm for twin lead, and strip lines. Tnx fer a fun list!
73 Jeremy w7eme
------------------------------
Message: 5
Date: Wed, 21 Feb 2007 07:04:53 +0000
From: Dave G4AON <[EMAIL PROTECTED]>
Subject: [Elecraft] K1 frequency drift observations
To: elecraft@mailman.qth.net
Message-ID: <[EMAIL PROTECTED]>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
When I built my K1 back in 2002 (serial 1154), I opted to use the
supplied 68 pF capacitor at C2. I found the drift figures worse than the
specification and changed the "NP0" ceramic capacitor for a polystyrene
one. The drift was just under 200 Hz per hour, while meeting
specification (just) it was always an irritation and noticeable on most
QSOs.
Looking at the problem with a little more science than emotion, it
appeared the drift was caused by too much negative temperature
coefficient (i.e. too much "polystyrene") and I replaced the 68 pF
capacitor with a local purchase ceramic one of zero temperature
coefficient one (I wonder if the one I fitted originally wasn't really
an NP0 type). The overall result, in a fairly stable room temperature,
is a drift of roughly 100 Hz per hour. The K2 drifts in an LF direction
when operating on 7 MHz, which seems to be the direction of drift for
others I've come across.
The frequency drift was measured with an external counter and "off air"
frequency standard. Over a two hour period the drift was lower in
frequency by 198 Hz, yet the display on the K1 didn't indicate any
frequency movement! In the past others and I have noticed a tendency for
the displayed frequency to "jump", usually by 200 Hz, especially when
using the CAL function after swapping band boards, using the RIT/XIT and
similar large and fast frequency changes. It would appear that slow
drift is not registering on the K1 display... Am I seeing things or is
this really the case? My assumption is the code is written to damp down
frequency display changes to avoid a flickering last digit, but appears
to result in a frozen display that can fool us into thinking a K1 is not
drifting when in reality it is.
Any thoughts?
Dave, G4AON
------------------------------
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End of Elecraft Digest, Vol 34, Issue 23
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