[1000mp] Yaesu FT1000 Key Clicks

[George, W5YR]

Thanks for the tips, Earl. I always monitor the time domain appearance of
the keyed waveform with a scope while concurrently observing the spectrum. I
will use the Tek 465B instead of the usual 20 MHz Goldstar monitoring scope
and measure the full rise and fall times for each radio per the 0-100%
convention..

What are your thoughts about the effects of receiver bandwidth and IF filter
shape, et al upon the user's perception of clicks from another station? I
realize that this introduces another variable into the situation: the other
op's receiver and his use of it. But, even when ARRL Labs uses an r-f
spectrum analyzer, the spectral plot they get is a function of the receiver
function of the SA and its settings.

I have found that with my crystal-filter 765 and K2 that a station may
appear to have fewer clicks over a given bandwidth than when I use the same
bandwidth setting on the PRO2 with its DSP IF filters. With a narrow DSP
filter tuned off the "main signal" many keying artifacts are audible whereas
with the broader crystal filters in the analog radios, the presence of the
keyed signal within the wider passband tends to obscure the artifacts.

73, George W5YR
w5yr@att.net


----- Original Message ----- 
From: "Earl W Cunningham" <k6se@juno.com>
To: <1000mp@mailman.qth.net>; <w5yr@att.net>
Sent: Tuesday, January 13, 2004 11:26 AM
Subject: Re: [1000mp] Yaesu FT1000 Key Clicks


> George, W5YR wrote:
>
> "I plan to repeat the keying spectrum tests using a variety of rise/fall
> times and receiving bandwidths and filter types in order to get some idea
> of the role the receiver plays in the "other" op's perception of the
> click situation. These findings will probably appear on Adam's website."
> ----------
> Please let me know when thry appear there.
>
> Bear in mind that (per W8WWV's o'scope plots) that when the 756Pro2's
> menu rise time setting is:
>
> 2 msec, the actual rise time is 2 msec.
> 4 msec, the actual rise time is 3 msec.
> 6 msec, the actual rise time is 4 msec.
> 8 msec, the actual rise time is 5 msec.
>
> Those values are from zero to peak amplitude, not from 10% to 90% as rise
> time is usually defined, so reduce those values by 20% if you prefer that
> convention.
>
> When you do the tests, it would be a good idea to monitor the keyed
> waveform to ensure that the actual rise times of the two radios are equal
> in their comparisons, i.e., don't rely on the rise time menu settings of
> each radio as being "honest" and equal to the other..
> ==========
>
> "While the rise and fall times have an effect upon the keyed spectral
> width and shape, I have found from examining the keying of various rigs
> that the shape of the keyed envelope plays an important role as well."
> ----------
> Particularly at the corners at the peak amplitude of the pulse, where the
> power is greatest.
>
> 73, de Earl, K6SE