[Elecraft] Elecraft. KAT1 ATU on 80m

Tue Jan 13 04:19:01 2004

I posted this query a few days ago and only got one response which I put
below. Thanks Thomas, but I haven't had chance to try the coiled coax yet.
Any other thought from you guys would be welcome as always.

BTW, anybody in the UK fancy a regular sked (mon to fri) at the unearthly
hour of 6.40z (CQ insomniacs!) ) for about 30 mins on 80m before I go to
work to help me improve my cw copy (12-15wpm), any offers gratefully
received. I call at this time around 3.550. I'm qrp with the K1 but dipole
works well and my cw is easy to copy.

73's
Martin
M0KWV
K1 #1534, K1-2, K1-4, Kat1

Thomas Beaudry <[email protected]> on 05/01/2004 12:01:01

To:    [email protected]
cc:

Subject:    Re: [Elecraft] Elecraft K1 on 80m

> Hi folks and happy new year to all. I'm a new ham with only 5 months
> experience on the air and use the K1 which is doing fb.

Congratulations and welcome!

> 40m has been awful
> lately in the evenings so thought I would use the holidays to change
> my ant
> from 40m dipole to 80m. The 80m dipole is in a straight line at about
> 30
> feet and the last few feet hang down vertically. It is fed using about
> 150
> feet of 50 ohm coax. with no balun. I have cut the dipole ends to get
> a swr
> of approx 1.5 at 3.500 to 1.7 at 3.560 as measured on an external
> watt/swr
> meter.

Sounds like my first antenna ages ago.  <ggg>

> I assume this is as good as I am likely to get.

Possibly.  It's good enough that you don't need to worry about it.

> It works great and I
> have had a host of contacts with good reports

Proof that it's as good as it needs to be.

> however, the K1 seems to have
> problems matching it. I use the kat1 ATU and when I go into tune mode
> it
> comes up with an swr of 1.1 (fine) but the output power does not match
> the
> set power eg 5 watts out = 3.5 watts setting, also current draw is
> often
> too high. The kat 1 had no problems with the 40m dipole with similar
> swr.

Could be RF from the antenna is getting on the outside of the coax and
getting back to your rig.  That RF could screw up control circuits.  It
can also cause the swr bridge to show a match that doesn't really
exist.  Some people will tell you that you need a balun to get rid of
RF on the outside of the coax.  Not true but may be easier since it is
light.  You can also get rid of the stray RF by coiling up the coax as
tight as you can, 10 - 15 turns would be good for 80M.  Whichever you
do, it has to be as close to the feed point as possible.

Also make sure that your coax is perpendicular to the antenna.  The
further from perpendicular (closer to parallel), the more RF is going
to be picked up.

> It's not a big problem but when the K1 takes much more than 1A, my
> little
> psu starts to go unregulated and I can hear the mains ripple on the
> audio.
> BTW when this happens does this mean that the transmitted signal gets
> degraded in any way or is it OK provided the input volts stay above
> 8.5V.
> Also will a 1.5A drain damage the K1 power stage?

If you can hear ripple in the audio, it's possible that you have it in
your transmitted signal as well.  Ask some of the stations you work.
They may realize that you're a beginner and are reluctant to mention it.

> Getting on 80m is good for me since there is a lot of good quality cw
> at my
> speed. The cw is coming along just fine with a combination of qso's,
> copying and reading from tapes and radio. I've knocked together a
> simple
> rough and ready single lever paddle from bits in the garage and it
> works
> well with the K1 built-in keyer, can't believe how easy it is to send
> nice
> smooth cw with the paddle, the poor old sk is getting dusty hi.
>
> I hope to add the 40m wires to the 80m dipole when I get the time to
> give
> me a dual bander (tri bander if you count 15m). I find 80m very noisy,
> is
> this normal or is it because the ant is nearer the house. One of the
> good
> things about cw is that noise doesn't really spoil the enjoyment
> provided
> that you can here the dits and dahs. The brain seems to just get used
> to it
> and filters it out.

The noise is normal.  The bands get noisier as you go down.  One of the
problems is that you are getting closer to the frequency of lightening.
  With experience, you'll notice that anytime there is a storm within
500 miles (~750 km.), you're going to hear the lightening crashes.

The other thing is that as you go down in frequency, the bands get
noisier with sun spot activity.  Since we're on a down slope of the sun
spot cycle now, 80M will be getting quieter.  That is why you're
getting all the contacts now.  A few years ago, 80M was too noisy for
anything other than local communications.  Now people are coming back.
In another two years, 80M will be quieter than 40M is now.  Except when
there is a storm near.  <ggg>

Guess I'm saying to enjoy 80M for the next 5 years or so with 40M as
your backup.  I prefer 80M myself for CW, everybody seems to be more
laid back.  Probably because of all the space available.

> Thanks to all in advance
>
> 73's
> Martin
> M0KWV
> K1 #1534, K1-2, K1-4, Kat1
>
>
>
>

Why not take a look at our Web site?
http://www.simoncarves.com

*************************************************************************
The information in this email and any attachments may contain
privileged and/or confidential information intended solely for
the use of the individual or entity to whom it is addressed.
If the reader of this email is not the intended addressee, or the
employee or agent responsible to deliver it to the addressee,
you are hereby notified that any dissemination, distribution or
copying of this communication is strictly prohibited.
If you have received this communication in error, please notify
me by telephone or email and delete all copies immediately.
*************************************************************************