Message-ID: <B11EEC44E7A24FD09CE3379CA2EB4F78@AGB>
From: "Graham" <g8fzk@g8fzk.fsnet.co.uk>
To: <rsgb_lf_group@blacksheep.org>
References: <20250.29213.qm@web86503.mail.ird.yahoo.com>
In-Reply-To: <20250.29213.qm@web86503.mail.ird.yahoo.com>
Date: Wed, 9 Dec 2009 23:31:05 -0000
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Subject: Re: LF: 500kHz simple 5W TX/RX transverter >>DATA MODES<<
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Alan,

If you  saw the  70  MHz    wspr tests I did  with  Gary  last  year .. I 
don't  think frequency  stability is a  issue  with  Joe's software !

In test's on 500 over the  years, the  original  MFSK system out performed 
the  other  systems tested , olivia came a close second, but  needs a 
linear system due to the  envelope  shaping ..pity as the  receive software 
has the  ability to  seek and  decode the  signal ... still waiting  for 
some one to  add a  real  arq function to one of the  modern data  packages, 
but  'they' all seem to  be  locked into a  disaster  email  delivery 
system's  .. what a disaster for the  casual chatter  ....... not that some 
of 'us' have  not  sent error corrected  emails on 500  .. sorry  could not 
resist it  :)

Im not  involved with  Rogers  project as such , other than  I was looking 
through the  back posts to the ref  and  noticed the  reference to  'wspr' 
,the  files are uploaded to the  uk500khz group, but  I notice there is not 
a  'G3XBM' page .. that may be a  useful  addition to link the  files 
together ...

73 - G ..

--------------------------------------------------
From: "ALAN MELIA" <alan.melia@btinternet.com>
Sent: Wednesday, December 09, 2009 10:32 PM
To: <rsgb_lf_group@blacksheep.org>
Subject: Re: LF: 500kHz simple 5W TX/RX transverter >>DATA MODES<<

>
> 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.
>
> Alan G3NYK
>
>
> --- On Wed, 9/12/09, Graham <g8fzk@g8fzk.fsnet.co.uk> wrote:
>
>> From: Graham <g8fzk@g8fzk.fsnet.co.uk>
>> Subject: LF: 500kHz simple 5W TX/RX transverter >>DATA MODES<<
>> To: rsgb_lf_group@blacksheep.org
>> Date: Wednesday, 9 December, 2009, 22:13
>>
>>
>>
>>
>>
>>
>>
>> All
>>
>> This  latest
>> addition to  the
>> HF / MF  tx convertor  opens the  door
>> to  data
>> communications  on 500 ... ranging  from
>> 'all'  the K1JT systems
>> through to  the  single carrier
>> multi  tone
>> systems  of
>> MFSK  ,  DOMINO and THOR  .. even
>> the  almost
>> forgotten  Amtor-arq  and Packtor modes , anyone
>> still  have
>> there pk232
>>
>> listed  are
>> data  modes that  may be  used with
>> non-linear systems :-
>>
>>
>> http://groups.google.com/group/uk500khz/web/meat-grinder-comms
>>
>> G..
>>
>>
>>
>>
>> From: Roger
>> Lapthorn
>> Sent: Tuesday, December 08, 2009 12:20 AM
>> To: rsgb_lf_group@blacksheep.org
>>
>>
>> Subject: LF: 500kHz simple 5W TX/RX
>> transverter
>>
>> Dear All,
>>
>> My WSPR tx up-converter has now been modified to
>> a full TX/RX tranverter suitable for WSPR, QRSS and
>> CW  in a
>> very simple way, making use of the FT817 split
>> facility which allows you
>> to RX on 500kHz and TX on 28MHz. By adding a series LC
>> between the TX PA and the
>> FT817 input/output RF connection (with back-to-back diodes
>> at the L and C
>> junction, this allows "pass through" from the
>> 500kHz ATU to the FT817 on RX
>> (tuned to 500kHz). On TX, the diodes conduct and the C part
>> is in parallel with
>> the first cap in the TX low pass filter. This scheme is now
>> working really well
>> with good RX sensitivity and no change in TX power out.
>>
>> Schematic of the
>> transverter is on my blog at http://g3xbm-qrp.blogspot.com/
>> . My
>> attempt to add it as an attachment to an email here earlier
>> failed.
>>
>> This more or less concludes my 500kHz experimenting, apart
>> from
>> getting a few more CW QSOs in the log. It's been great
>> fun all the way with lots
>> of support from folks here. I was going to try 136kHz, but
>> think I will now give
>> this a miss for now.
>>
>> 73s
>> Roger G3XBM
>> -- 
>>
>> -------------------------------------------------------------
>> http://g3xbm-qrp.blogspot.com/
>> http://www.g3xbm.co.uk
>> G3XBM
>>  GQRP 1678      ISWL G11088
>>
>>
>>
>>
>>
>
>