[CQ-Contest] New Contest

[Tom Osborne]

Hi All

Had lots of time on my hands at the campground this weekend.
Thought of a good new contest.

1.  The contest period would consist of any 1 hour period of a
pre-determined 12 hour contest period.

2.  The log would consist of only 1 contact.

3.  The winner would be determined by the station that worked
another station the greatest distance from his location.

4.  The distance between your location and the other stations
location would be computed using the short path distance,
regardless of which path was used.

5.  You can call CQ or answer a CQ.  If you call CQ, you don't
have to answer a station unless you think this might be the
winning contact.  This gives other stations a chance to work you
for their best DX.  If you answer a CQ, you can only answer 1 CQ,
hoping that this will be the winning contact.  You can send in
either of these contacts for your official log.

6.  Packet assistance is NOT allowed.

Think about it, this could be fun!!  73
Tom W7WHY


--
CQ-Contest on WWW:        http://lists.contesting.com/_cq-contest/
Administrative requests:  cq-contest-REQUEST at contesting.com


>From Marijan Miletic" <Marijan at Miletic.net  Tue May 29 00:47:29 2001
From: Marijan Miletic" <Marijan at Miletic.net (Marijan Miletic)
Date: Mon, 28 May 2001 23:47:29 -0000
Subject: [CQ-Contest] MP clicks
References: <200105282301.f4SN1dV22807 at paris.akorn.net>
Message-ID: <000501c0e7d0$99726a00$2c48fea9 at pentium>


----- Original Message -----
From: "Tom Rauch" <w8ji at contesting.com>
To: <cq-contest at contesting.com>; "Marijan Miletic" <Marijan at Miletic.net>
Sent: 28. maj 2001 22:59
Subject: Re: [CQ-Contest] MP clicks


 > > George, W2VJN did measurements at the highest practical Morse code speed
 > > for direct human copy of 40 wpm.  Dot pulses are less then 20 msec short
 > > and 10% rise and fall times is a good engineering practice shaping.  Rest
 > > of the problem is mainly in the RX AGC circuits...
 >
 > George and I are talking off the reflector. I'm sure we will either
 > agree or agree to disagree with good reason soon.
 >
 > AGC is NOT an issue because the main signal is outside the
 > passband of the receiver. Receiver AGC is not the cause of
 > excessive bandwidth of CW signals. It may make signals inside
 > the passband sound "thumpy", but since those signals are inside
 > the passband they will wipe out weaker signals anyway..thumps or
 > not.
 >

AGC will generate "thumpy" received CW signal within filter bandwidth whenever
the attack time is not significantly shorter from transmitted signal leading
edge and delay considerably longer of the dots time length.  This causes more
problems then genuinely wide CW signals...

 > The ARRL states 5 mS rise and fall is a good value for virtually all
 > applications and they allow a poor one pole filter shape. I am using
 > 7mS on my FT1000 with absolutely no ill effects. 5 mS and longer
 > is clearly no problem. Even when I have a marginal signal on 160
 > meters with lot's of noise spikes, switching the click-filter in and
 > out makes no difference.
 >

160m is usually slow DX mode while a lot of  CW is often transmitted in high
speed break-in style just like this weekend.
5 ms shaping would waste about 25% of energy in the repeated 20 msec dots with
1:1 baseline weighting! 2 ms stays within 10%...
5 ms R/C shaping of perfect 20 msec square dots might otherwise introduce
distorted 25:15 dot/space ratio.

 > > I don't think I'll ever see dying CW shaping with anything more then
 > > simple RC circuit.  DSP can certainly do better but on the expense of the
 > > energy transmitted!
 >
 > Energy transmitted outside the passband of the receiver does no
 > good at all, unless our goal is the mess up the other guy.
 >
 > We do not need a DSP system to have better shaping than a
 > simple R/C shaping provides, nor do we need to decrease
 > transmitted  "energy". If we want more energy, we can simply turn
 > up the weight control. We'll have more energy on the operating
 > frequency, and not up and down the band where it only serves to
 > cause problems.
 >

R/C does exponential shaping while DSP can provide much more efficient shapes
widely used in data windowing.
I always assume 1:1 dot/pause weighting and peak envelope power limited TX.
There is not much room to 3:1 dash/pause ratio while trying to preserve a good
Morse readability.  Otherwise we might consider 2:1 dots and 4-6:1 dashes...

 > IMO, we should all be using the ARRL's recommended rise and fall
 > times of 5 mS and longer. Otherwise we need to keep our
 > transmitters a reasonable distance away from other people. Those
 > are the only choices.
 >
 > Shaping can be very important. Op-amps are cheap and easy to
 > use.
 >
 > 73, Tom W8JI
 > W8JI at contesting.com
 >

Apart from frequency distance, we can always slow down the CW speed but the
opposite is often the case with PC contest code generation...

73 de Mario, S56A, N1YU


--
CQ-Contest on WWW:        http://lists.contesting.com/_cq-contest/
Administrative requests:  cq-contest-REQUEST at contesting.com