[UK-CONTEST] FT1000MP MkV Shift and Width Controls
Douglas Maxwell
douglas.maxwell at virgin.net
Sat Dec 24 03:53:54 EST 2005
Hi Paul,
I also posted the article at the following address:
http://2m0vlf.proboards57.com/index.cgi?board=discussion&action=display&thread=1135185890
The formatting seems to have been stripped from the diagrams I posted to the
group. I was beginning to think I was the only one who thought it needed
further explanation. I wanted to be able to adjust these controls and get it
right first time, instead of the suck it and see approach. The trouble is
that the change these controls make is difficult to quantify due to the
number of variables:
IF stage filter combinations i.e. 500/none, 500/500, 250/none, 250/250 etc
Filter widths
Filter types i.e. Mechanical, crystal
Menu settings i.e. DSP or analogue demodulator, DSP receive width 100-3100
or 300-2800, 10 or 20Hz for shift control etc.
The diagrams aren't the best, but let me know if you agree or disagree with
them.
Cheers
Doug
----- Original Message -----
From: "Paul G3WYW" <paul at kbcomms.demon.co.uk>
To: "Douglas Maxwell" <dcmaxwell at iee.org>
Sent: Friday, December 23, 2005 11:46 PM
Subject: Re: [UK-CONTEST] FT1000MP MkV Shift and Width Controls
> Hi Doug,
>
> Not sure whether you have had any responses to your email, but I had some
> trouble understanding your diagrams. My email server seems to have removed
> any formatting information so the diagrams look wierd and not easy to
> understand.
>
> Can you please send me them again, perhaps inside a word document or a
.zip
> file where the information is not lost.
>
> Best Regards
>
> Paul g3wyw
>
>
> ----- Original Message -----
> From: "Douglas Maxwell" <douglas.maxwell at virgin.net>
> To: <uk-contest at contesting.com>
> Sent: Wednesday, December 21, 2005 12:24 PM
> Subject: [UK-CONTEST] FT1000MP MkV Shift and Width Controls
>
>
> Hi all,
> When I look at the manual for the MkV, I always get stuck on the
> pictorial description of the shift control operation. I think it's wrong.
My
> own method for picturing the action of these controls is the following
> (frequency increases toward the right):
>
> USB
> __________
> __________________|___/ \___ No Shift
> __________
> __________________|/ \_____ CCW Shift
> __________
> __________________|______/ \ CW Shift
>
>
> __________
> __________________|___/ \___ No Width
> ________
> __________________|______/ \___ CCW Width
> ________
> __________________|___/ \_____ CW Width
>
> LSB
> __________
> ___/ \___|_________________No Shift
> ___________
> / \ _____|________________ CCW Shift
> __________
> ______/ \|________________ CW Shift
>
>
> __________
> ___/ \___|_________________No Width
>
> _________
> _____/ \___|_________________CCW Width
>
> ________
> ___/ \_____|_________________CW Width
>
>
> As can be seen from the above diagrams, in either USB or LSB the action of
> both controls is constant i.e.
> 1) The shift control moves the passband in the direction it is rotated.
> 2) The width control brings in the skirt of the passband it is rotated
> toward.
>
> Audio frequency is mode dependant, so to get rid of interfering signals it
> helps me to imagine the following:
>
> LSB USB
> __________ __________
> ___/ \___|___/ \___
> H L L H
>
> Therefore:
> USB
> 1) Higher pitched interfering signals will be above you in frequency.
> 2) Lower pitched interfering signals will be below you in frequency.
> LSB
> 1) Higher pitched interfering signals will be below you in frequency.
> 2) Lower pitched interfering signals will be above you in frequency.
>
> With a bit of practice you can now hear the interfering signal and know
> which way to rotate the shift, width or shift/width controls to
effectively
> eliminate it.
>
> If you need to get rid of interfering signals on both sides.
> USB
> Both shift and width controls turned CCW.
> LSB
> Both shift and width controls turned CW.
>
> The effectiveness of the width control is dependant on wither both 2nd and
> 3rd IF filters are fitted, but with both fitted (and with menu 1-2 shift
> step = 10Hz) each graduation mark equates to approx 250Hz worth of change.
> This means that for USB CW with cascaded 500Hz filters and shift and width
> both CCW by 1 graduation you have almost closed the passband. Try 1/2
> graduation mark in this situation for weak signal work and you have an
> effective 250Hz filter.
>
> I hope that this will encourage more people to explore their MkV as it is
a
> truly awesome machine when used to the utmost of it's capabilities. I hope
> it also dispels the myth that you must have a MkV fully loaded to get any
> performance from it.
>
> P.S. I use the free DX LAB software suite for experimenting, in particular
> Winwarbler's PSK31 waterfall to observe shift and width effects. Also a
> lesser known fact, that the C-IV commander software that also comes
bundled
> allows individual control of 2nd and 3rd IF filter insertion. This means
> with both 500Hz filters installed and with rig control enabled you can
> choose whether you wish 2nd, 3rd or 2nd and 3rd filters in-line.
>
> Have a Merry Christmas all
>
> Doug
> GM0ELP
>
>
>
>
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