Hello Paul,
in the current SlowJT9 version double and quadruple tone spacing can be
selected.
If it is of any help I can allow any value for increased tone spacing.
The practical limit will be the TX bandwidth.
But for JT9-5 the signal bandwidth is only 2.6Hz, so anything up to 1000 should
fit within the TX bandwidth.
73, Rik ON7YD - OR7T
________________________________________
Van: rsgb-lf-group@groups.io <rsgb-lf-group@groups.io> namens N1BUG
<paul@n1bug.com>
Verzonden: maandag 31 december 2018 16:54
Aan: rsgb_lf_group@blacksheep.org; rsgb-lf-group@groups.io; Discussion of the
Lowfer (US, European, & UK) and MedFer bands; 600MRG@mailman.qth.net
Onderwerp: Re: [rsgb-lf-group] Bad news / help request
Duh! Scratch item 3. Of course that won't work as it will destroy
the JT9 tone spacing!!
Paul
On 12/31/18 8:59 AM, N1BUG wrote:
> So, the latest SlowJT9 test is completed. I regret I was not able to
> run one night on 630m as planned.
>
> I used a QRP Labs Ultimate 3S beacon transmitter for these tests.
> Yesterday I checked my ability to use JT9-5 for QSOs and found that
> I have none! My FT-2000 transceiver has too much drift to be of any
> use on JT9-5 and is very marginal even for JT9-2. What a huge
> disappointment, though it did not come as any surprise.
>
> I can think of several ways to solve this but am not sure any of
> them can save some part of this winter season:
>
> 1. Add insulation and a heater to the FT-2000 TCXO area. I will try
> this but I am not convinced I can make enough improvement. The drift
> is really ugly!
>
> 2. Replace the FT-2000 TCXO with an outboard programmable GPS
> referenced oscillator, for example a Leo Bodnar unit. The trouble
> with this is I do not have sufficient knowledge or experience to
> know what kind of problems might be encountered. The GPSDO is enough
> of an investment to kill any and all other attempts at a resolution
> if I am unable to make it work.
>
> 3. Use a divide-by-100 circuit with the FT-2000 operating at 13.6
> MHz instead of a LO/mixer converter from 10 MHz. This should reduce
> drift to the order of 0.1 Hz, probably quite acceptable. So far I
> have not found a divide-by-100 circuit using a modern/available part.
>
> 4. Run away from the junk FT-2000 completely, using audio to 136 kHz
> converter for Tx and 136 kHz to audio converter for Rx. This is
> finally the direction I want to go but there seems to be much
> learning left to do and a lot of building. It's probably not a
> solution which can be completed in time for this winter season.
>
> If anyone has experience in any of these areas and is willing to
> share knowledge, please get in touch with me. This may be the last
> solar minimum for me, and I would like to make some LF/MF DX QSOs
> before these incredible conditions fade away.
>
> 73,
> Paul N1BUG
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