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Message-ID: <241919.87622.qm@web86503.mail.ird.yahoo.com>
Date: Thu, 10 Dec 2009 11:27:59 +0000 (GMT)
From: ALAN MELIA <alan.melia@btinternet.com>
To: rsgb_lf_group@blacksheep.org
In-Reply-To: <9afca2640912091527s766a7e64wa10ad3be7c7f6f08@mail.gmail.com>
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Subject: Re: LF: 500kHz simple 5W TX/RX transverter >>DATA MODES<<
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Hi Roger yes you are right of course its the drift within a qso period or=
 even an over that is most important. Very Good.

I wonder whether the use of 10MHz as an "IF" would be a possibility? This=
 would allow readily available TCXOs or even OCXOs to be used for the LO.=
 I guess the split should be enough to allow your filter/diplexor to work.=
 It obviously only removes one source of drift, one cant do much about the=
 817, but that also should be less at 10MHz?

Alan G3NYK

--- On Wed, 9/12/09, Roger Lapthorn <rogerlapthorn@gmail.com> wrote:

> From: Roger Lapthorn <rogerlapthorn@gmail.com>
> Subject: Re: LF: 500kHz simple 5W TX/RX transverter >>DATA MODES<<
> To: rsgb_lf_group@blacksheep.org
> Date: Wednesday, 9 December, 2009, 23:27
> With the transverter "in the
> open" (rat's nest) on the desktop there is a
> warm-up drift of about 40Hz HF until things settle down.
> This has not been an issue with WSPR as the drift in a
> single TX slot is only about 1-2Hz usually (WSPR copes with
> this) and it soon settles down to 0Hz drift. I have not
> tried QRSS but imagine you'd have to ensure the xtal
> oscillator is made more thermally stable for v.slow QRSS,
> but would guess it would be OK for some moderate QRSS
> operation. Putting the whole unit in a box should help.
>=20
>=20
> My little circuit works, but is surely capable of much
> improvement, HI.
>=20
> 73s
> Roger G3XBM
>=20
> 2009/12/9 ALAN MELIA <alan.melia@btinternet.com>
>=20
> Sounds good Roger and Graham...
> what it the stability like the problem with
> transverters/upconverters normally is that while ok for some
> modes they are  often not stable enough for the very weak
> signal modes. These are modes where you need to know the
> frequency of a station very accurately because you will not
> hear it, or it will only pop above the noise for short
> periods.
>=20
>=20
>=20
>=20
> Alan G3NYK
>=20
>=20
>=20
>=20
>=20
> --- On Wed, 9/12/09, Graham <g8fzk@g8fzk.fsnet.co.uk>
> wrote:
>=20
>=20
>=20
> > From: Graham <g8fzk@g8fzk.fsnet.co.uk>
>=20
> > Subject: LF: 500kHz simple 5W TX/RX transverter
> >>DATA MODES<<
>=20
> > To: rsgb_lf_group@blacksheep.org
>=20
> > Date: Wednesday, 9 December, 2009, 22:13
>=20
> >
>=20
> >
>=20
> >
>=20
> >
>=20
> >
>=20
> >
>=20
> >
>=20
> > All
>=20
> >
>=20
> > This  latest
>=20
> > addition to  the
>=20
> > HF / MF  tx convertor  opens the  door
>=20
> > to  data
>=20
> > communications  on 500 ... ranging  from
>=20
> > 'all'  the K1JT systems
>=20
> > through to  the  single carrier
>=20
> > multi  tone
>=20
> > systems  of
>=20
> > MFSK  ,  DOMINO and THOR  .. even
>=20
> > the  almost
>=20
> > forgotten  Amtor-arq  and Packtor modes , anyone
>=20
> > still  have
>=20
> > there pk232
>=20
> >
>=20
> > listed  are
>=20
> > data  modes that  may be  used with
>=20
> > non-linear systems :-
>=20
> >
>=20
> >
>=20
> > http://groups.google.com/group/uk500khz/web/meat-grinder-comms
>=20
> >
>=20
> > G..
>=20
> >
>=20
> >
>=20
> >
>=20
> >
>=20
> > From: Roger
>=20
> > Lapthorn
>=20
> > Sent: Tuesday, December 08, 2009 12:20 AM
>=20
> > To: rsgb_lf_group@blacksheep.org
>=20
> >
>=20
> >
>=20
> > Subject: LF: 500kHz simple 5W TX/RX
>=20
> > transverter
>=20
> >
>=20
> > Dear All,
>=20
> >
>=20
> > My WSPR tx up-converter has now been modified to
>=20
> > a full TX/RX tranverter suitable for WSPR, QRSS and
>=20
> > CW  in a
>=20
> > very simple way, making use of the FT817 split
>=20
> > facility which allows you
>=20
> > to RX on 500kHz and TX on 28MHz. By adding a series
> LC
>=20
> > between the TX PA and the
>=20
> > FT817 input/output RF connection (with back-to-back
> diodes
>=20
> > at the L and C
>=20
> > junction, this allows "pass through" from
> the
>=20
> > 500kHz ATU to the FT817 on RX
>=20
> > (tuned to 500kHz). On TX, the diodes conduct and the C
> part
>=20
> > is in parallel with
>=20
> > the first cap in the TX low pass filter. This scheme
> is now
>=20
> > working really well
>=20
> > with good RX sensitivity and no change in TX power
> out.
>=20
> >
>=20
> > Schematic of the
>=20
> > transverter is on my blog at http://g3xbm-qrp.blogspot.com/
>=20
> > . My
>=20
> > attempt to add it as an attachment to an email here
> earlier
>=20
> > failed.
>=20
> >
>=20
> > This more or less concludes my 500kHz experimenting,
> apart
>=20
> > from
>=20
> > getting a few more CW QSOs in the log. It's been
> great
>=20
> > fun all the way with lots
>=20
> > of support from folks here. I was going to try 136kHz,
> but
>=20
> > think I will now give
>=20
> > this a miss for now.
>=20
> >
>=20
> > 73s
>=20
> > Roger G3XBM
>=20
> > --
>=20
> >
>=20
> >
> -------------------------------------------------------------
>=20
> > http://g3xbm-qrp.blogspot.com/
>=20
> > http://www.g3xbm.co.uk
>=20
> > G3XBM
>=20
> >  GQRP 1678      ISWL G11088
>=20
> >
>=20
> >
>=20
> >
>=20
> >
>=20
> >
>=20
>=20
>=20
>=20
>=20
>=20
> --=20
> -------------------------------------------------------------
> http://g3xbm-qrp.blogspot.com/
> http://www.g3xbm.co.uk
>=20
> G3XBM    GQRP 1678      ISWL G11088
>=20
>=20