R: LF: Re: Bad news / help request

["marcocadeddu@tin.it" <marcocadeddu@tin.it>]

Paul,

I never seen the FT 2000 so made a search on the web for the manual hoping to find a feature like my old TS950.. but unfortunately found no provision for an external frequency reference (in my TS950 there is the possibility to feed 10 kHz external reference) so the only chance on my opinion is to replace the original TCXO with another oscillator maybe GPS or Rb disciplinated.. or find the internal reference derived from the divided TCXO (probably in the range 1÷10 kHz) and switch to a suitable stable external reference.
Of course on a quite new generation transceiver this could be almost a surgical operation :-( but maybe the Yaesu designer although didn't make available a simple external jack.. didn't squeeze this vital part in no accessible area.

HNY Paul
HNY LF&MF

Marco, IK1HSS

----Messaggio originale----
Da: paul@n1bug.com
Data: 31-dic-2018 16.54
A: "rsgb_lf_group@blacksheep.org"<rsgb_lf_group@blacksheep.org>, "rsgb-lf-group@groups.io"<rsgb-lf-group@groups.io>, "Discussion of the Lowfer (US, European, & UK) and MedFer bands"<lowfer@mailman.qth.net>, "600MRG@mailman.qth.net"<600MRG@mailman.qth.net>
Ogg: LF: Re: 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