> 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.
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.
> 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.
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@contesting.com
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>From Michael Tope" <W4EF@dellroy.com Tue May 29 00:14:49 2001
From: Michael Tope" <W4EF@dellroy.com (Michael Tope)
Subject: [CQ-Contest] MP vs 830
References: <Pine.LNX.4.21.0105281223200.19357-100000@dayton.akorn.net>
Message-ID: <01e901c0e7cb$fedabfa0$6401a8c0@neptune>
Hi Bill,
I doubt there are many 830's around that are still under warranty, so do
what I did
to my old Ten-Tec Paragon and add a couple of RCA jacks to the rear apron for
an external receive loop thru. This will allow you to insert external
attenuators,
preamps, and receive antennas without having to fuss with a DIN connector. For
normal operation, all you need to do is install an RCA jumper. In fact this
is how
the TS-950DSX is setup from the factory (the TS-940 still used the DIN plug).
Now if we could just figure out how to slow down the VFO tuning rate!!
73 de Mike, W4EF........
----- Original Message -----
From: "Bill Fisher W4AN" <w4an@contesting.com>
To: <cq-contest@contesting.com>
Sent: Monday, May 28, 2001 9:30 AM
Subject: [CQ-Contest] MP vs 830
>
>
> We used a TS830 this weekend to run, and I thought I would pass one a few
> observations:
>
> - I like the receiver better. Can't explain it. I just do.
>
> - The noise blanker in the 830 works. The MP's doesn't. We had a bit of
> line noise and the 830 took it right out without destroying signals on the
> band. Why can't the MP do the same?
>
> - The 830's VFO tunes way too fast, but for the run radio it isn't a big
> deal.
>
> - I hate DIN plugs. The MP has all the right connectors and front panel
> controls. Doing an external receive antenna on the 830 involves some kind
> of home brew box.
>
> - The 830 has 20db of attenuation or none. That is a bummer at times.
>
> - The 830 has less in-band phase noise. At least I perceived that to be
> true. I have never measured it.
>
> - No VFO lock on the 830 can spell trouble. :)
>
>
>
> I guess the bottom line is that the MP has all the right controls and all
> the right connectors. However, it is disappointing that the receiver of a
> radio that was produced 25 years ago is better.
>
> 73
>
> Bill
>
>
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>
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