Return-Path: Received: from mtain-dh12.r1000.mx.aol.com (mtain-dh12.r1000.mx.aol.com [172.29.65.32]) by air-de01.mail.aol.com (v129.4) with ESMTP id MAILINDE013-5ea44c1f2a8c30c; Mon, 21 Jun 2010 05:02:04 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-dh12.r1000.mx.aol.com (Internet Inbound) with ESMTP id 5611638000120; Mon, 21 Jun 2010 05:02:02 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1OQcrU-00021n-Qf for rs_out_1@blacksheep.org; Mon, 21 Jun 2010 10:00:12 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1OQcrT-00021e-9N for rsgb_lf_group@blacksheep.org; Mon, 21 Jun 2010 10:00:11 +0100 Received: from out1.ip08ir2.opaltelecom.net ([62.24.128.244]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1OQcrR-0005vE-8t for rsgb_lf_group@blacksheep.org; Mon, 21 Jun 2010 10:00:11 +0100 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AgMFALPGHkxUDYRN/2dsb2JhbACBQ51GcsAVgluCQAQ X-IronPort-AV: E=Sophos;i="4.53,452,1272841200"; d="scan'208,217";a="451158489" Received: from host-84-13-132-77.opaltelecom.net (HELO laptopcore2) ([84.13.132.77]) by out1.ip08ir2.opaltelecom.net with ESMTP; 21 Jun 2010 10:00:00 +0100 From: "g3zjo" To: Date: Mon, 21 Jun 2010 09:59:59 +0100 Message-ID: <000001cb1120$20c6b470$0202a8c0@laptopcore2> MIME-Version: 1.0 X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.2616 Importance: Normal In-Reply-To: <1A277397AD72498D97B7D9CD2F7B3CA5@AGB> X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2670 X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: RE: LF: Re: 137.500 kHz ROS beacon Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01CB1128.828D8D70" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.3 required=5.0 tests=HTML_50_60, HTML_FONTCOLOR_UNKNOWN,HTML_MESSAGE autolearn=no version=2.63 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false x-aol-global-disposition: G x-aol-sid: 3039ac1d41204c1f2a8a5620 X-AOL-IP: 193.82.116.20 ------=_NextPart_000_0001_01CB1128.828D8D70 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit A little finger trouble from G :- 3) Non linear PA is required He means:- 3) No linear PA is required Eddie -----Original Message----- From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Graham Sent: 21 June 2010 00:19 To: rsgb_lf_group@blacksheep.org Subject: Re: LF: Re: 137.500 kHz ROS beacon Ok Roger Well as you will of noted Mr Ros had a bit of a bumpy ride with our friends over the pond , so having a data system coded for MF was , perhaps a bit of a unexpected out come from my initial request , however ... we have one ..... 2) Spread spectrum .. well that is where it all started to fall apart ...... yes the term is reasonably close , but not close enough to fully qualify , for example F5WK is working on a pic based translator to enable a dds to be driven directly from the ros software .. the tx tones are defined by a look up table .. not exactly spread spectrum in the military sense ..yes there is a mixing of digital noise with the tx data stream , but as everyone is using the same prog free , then its not particularly secret ...unlike say jolly windows , that every one uses without access to the source code ....mfsk with fec may of been a more fitting description .. but the post is history as was/is the ensuing flap .. The mode deploys full power to each tone burst , ie a mfsk, phase continues modulation scheme , the average power is less than 100% peak as the system seems to tx short ms pulses ..may be slightly wrong on that , but gaps do appear causing my carrier led to flicker on tx 2) bandwidth is as advertised , the ros -mf 1 & 7 is approx 98 Hz wide , coded to fit inside the (new ?) 100 Hz data allocation on 500 .. by inspection the modulation seems to be very clean with no over shoot , unlike mfsk that seems to spread quite badly , I note that 137K band plans talk of 200 hz data bw 3) Non linear PA is required , the smart x2 harmonic amplifier Gary and my self deployed gives a work-round to the logic drive problem , Gary is transverting to 137 khz from HF with a linear transverter ... however the class d/e amp would half the frequency and modulation , so picking the x2 harmonic produced a drive carrier of 274 khz , which then reduced to 137 at the Ae ...... 4) Well its a free system ...... its running better as time go's on and evolving , some beacon modes are now available , cut and paste , and the e-mail qsl seems to work nicely 5) I would say it already is , running 1 watt to my Ae I can obtain 100% decodes from the delft web-sdr on 500 Khz in mf-1 mode , 2 to 3 watts for mf-7 , that's 350 miles , on 7 meg in qso with co2dc I have taken 100% print with him running 250 mW to the Ae with 50 mW drive to my Ae on 500 , print was 100% in Harrogate, in tests last month , Grays test on 137 as reported by F5WK , was under the visible level on the spectrum plot , but was decoding. 1) facts and figures ..well I don't really know .Mr Ros has the info .. but its not for publication .... this is perhaps a sticky point .. but while it lasts its showing what can be achieved . wspr is a time locked array processed system , using best fit matching , ros is a free running live data system, that is using digital noise reduction / cancellation to recover the data and as such are not really compatible , it looks to be on the lines of the noise reduction used in the military satellite systems of the 1980/1990 .. but in a much reduced bandwidth, making use of modern pc power ... reception of the initial sync frame is essential .. this process is much more robust than the main data flow , but dose present a problem with long qsb , unlike wspr that is partitioned >From my own experience as was Michel , I have seen the low baud rate ros system produce 100% print , when the signal could not be viewed on spec lab or detected by headphones .. so I think 'we' are working below the noise , co2dc has intimated that the system provides a increase of 20 dB over the psk31 system over the path co/vk , high immunity to phase distortion is also provided by the modulation system. Ok Roger , I hope that fills in the gaps ... at the moment you still need the traditional audio to rf translation , however f5wk is working on a pic system and the x2 harmonic amp provides a work round for classe/d amps .. but you do need to generate on the intended Ae frequency to use the amp. 73 - G .. Nb .. There may be some mileage in using a logic gate digital mixer to get on to frequency ........ would need a x2 doubler (logic) to get over the logic drive .. but if it works .. opens up 500/137 to a lot more data com's , bit of a odd concept . but if it works .. ? From: Roger Lapthorn Sent: Sunday, June 20, 2010 9:41 PM To: rsgb_lf_group@blacksheep.org Subject: Re: LF: Re: 137.500 kHz ROS beacon Graham, I'm behind on ROS progress so have a few questions please, if you've time: 1. How does ROS compare on a weak signal "effectiveness" factor with modes like QRSS3, 10 etc and with WSPR? Is there a "dB better than" estimate for ROS in its various forms? 2. What sort of bandwidths does ROS occupy on these LF tests? I appreciate it is spread spectrum, so there's not much power at any time on any frequency. 3. What sort of TX PA is needed - linear or non-linear? 4. Is the software less clunky than when I looked a few months back? 5. Is it going to be a serious contender for real QRP buffs like me? 73s Roger G3XBM On 20 June 2010 20:46, Graham wrote: ''''for instance the French stn F5WK cannot hear you''''' Well , yes , that's the point of it all , no noise, no trace just 100% pure digital data rolling over the land , like the un-seen fog of progress IARU - R-1 plan .. 137.4 to 137.6 digital modes , with the note that CW is 'not allowed' I think the test and the frequency went fully to 'to plan' and paves the way for a magnitudinal increase in data use on 137 , to date limited by bandwidth to psk31 , ros-mf by design occupying on 50% of the allowable space on 137 and 99% of the 100Hz allocations for 500K. and passing via a non linear system , how long will it before the first live data qso over the pond ? G . From: mal hamilton Sent: Sunday, June 20, 2010 6:30 PM To: rsgb_lf_group@blacksheep.org Subject: Re: LF: Re: 137.500 kHz ROS beacon Gary There are too many variables with these experiments for instance the French stn F5WK cannot hear you but you are S5 solid on 137.5 here at my qth The RX stations antennas need to be analyised otherwise it misrepresents what you are doing. Can u pse use frequencies below 136.5 kcs otherwise there is a problem with EU and Russian stations using the area 137 - 137.778 kcs for QRS acty. also this is the DX window area for the USA and others. 73 de mal/g3kev ----- Original Message ----- From: Gary - G4WGT To: rsgb_lf_group@blacksheep.org Sent: Sunday, June 20, 2010 4:31 PM Subject: Re: LF: Re: 137.500 kHz ROS beacon Hi Mal, Thank you for your report & comments. The mail you replied to gives all the details of equipment in use for the test beacon. I would like to be able to have a QSO using morse but I have to admit to a complete loss of confidence as I have not used the mode for 25 years which was one year after I passed the test in 1984. Looking back, letting it go was a silly thing to do. I do enjoy testing out these "weak signal" modes & in the report I received from Michel F5WK last night he wrote that he could not hear the signal or even see it on SpecLab but he got a complete decode. So as a weak signal communication mode it works. Just to elaborate on the antenna, it is a 12 metre base loaded vertical with a small elevated inductor of 500uH at about 9 metres & a 1 x 3 metre capacity top with a 120uH spiral inductor. In my small garden I have no space to go outwards only upwards. 73, Gary - G4WGT. On 20 June 2010 13:48, mal hamilton wrote: Gary If that was you last nite on 137.5 kcs you were strong enough for cw or qrs3 no need to struggle with decodes from elswhere. also I had a qso with G3XIZ this morning on 137.0 kcs and got 599, he was 569. Not sure what antenna u were using but it was putting out a fair signal to this qth. Your radiators are probably acting as an antenna above earth. de mal/g3kev ----- Original Message ----- From: Gary - G4WGT To: LF Group (RSGB) Sent: Sunday, June 20, 2010 12:07 PM Subject: LF: 137.500 kHz ROS beacon Hi LF, Having successfully bench & on-air tested a x2 harmonic amplifier method of driving my G0MRF Class D LF transmitter, I ran a beacon last night (Saturday 19th) on 137.500 kHz. An extract from my previous e-mail description is shown at the end. Using the equipment & method described below, the ERP from my 12 metre vertical antenna was around 150mW. The mode was ROS MF-1, 100 Hz bandwidth. I received the following report from Michel, F5WK in JN18HP, a distance of 410 miles (661 kilometres) in daylight. >> Not even a faint trace on a QRSS3 spectrum but: >> RX1: 19:23 @ 5.9 Hz: 9 -37 dB >> RX1: 19:28 @ 5.4 Hz: O4WGT -34 dB >> RX1: 19:33 @ 5.4 Hz: G4WGT -31 dB The x2 harmonic low level amplifier is a simple way of driving a Class D type of transmitter which employs a divide by 2 drive chain. My limitation with multi tone drive is that my DDS VFO will only produce 2 frequencies ie. the main frequency & a CW/Rx offset which has previously limited me to 2 tones as with RTTY & DFCW modes. Please bear in mind that it will not be suitable for modes like PSK were tones are transmitted simultaneously. At the moment the 2 small PCB's are precariously lying on the desk, when I have cased them I will publish the circuit & pictures. 73 Gary - G4WGT. *********************************************** After a few days experimenting & bench testing a method of driving my G0MRF Class D Tx on the 137.000 kHz band from my linear transverter I finally constructed a harmonic amplifier producing a 274.000 kHz signal from 137.000 kHz input. An "on-air" trial was conducted resulting in a QSO with Graham G0NBD on 137.000 kHz using ROS data mode software. My thanks to Graham for his ideas & tests. The mode used was ROS MF-7. The equipment used for the QSO was as follows. Kenwood TS-440 to my LF-MF linear transverter producing the 137.000 kHz signal, followed by a tuned harmonic circuit & buffer amplifier whose output was 274.000 kHz therefore at x2 drive for the Class D Tx. The x2 signal is then divided by the Tx driver chain in the normal way to provide 137.000 kHz to the PA. This method should also work well using WSPR & other similar modes. ********************************************* -- http://g3xbm-qrp.blogspot.com/ http://www.g3xbm.co.uk http://www.youtube.com/user/g3xbm G3XBM GQRP 1678 ISWL G11088 ------=_NextPart_000_0001_01CB1128.828D8D70 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

A little finger trouble from G :-

 

= 3)       Non linear  PA  is&nbs= p; required

 

He means:-

 

3) No line= ar PA is required

 

Eddie

 

-----Original Message-----
From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksh= eep.org] On Behalf Of G= raham
Sent: 21 June 2010 00:19
To: rsgb_lf_group@black= sheep.org
Subject: Re: LF: Re: 13= 7.500 kHz ROS beacon

 

Ok Roger=

 

Well = as you  will  of  noted Mr Ros had a  bit  of a  bumpy ride with=   our  friends over  the  pond , so  having a  data  system  coded  for  MF was , perhaps a = bit  of a  unexpected out come  from my  initial  reque= st , however ... we have  one .....

 

2) Spread&= nbsp; spectrum .. well  that is where  it all  started to  fall apar= t ......  yes the  term is  reasonably  close= , but  not  close enough to  fully  qualify , for&nb= sp; example F5WK is  working on a  pic based translator  to=   enable  a  dds  to be  driven  directly = from the  ros  software ..  the  tx tones are  def= ined by  a  look up  table .. not  exactly spread spect= rum in the  military  sense ..yes there  is a  mixing&nbs= p; of  digital  noise with the  tx data  stream , but=   as everyone  is using the  same  prog free , then  it= s not  particularly secret ...unlike  say  jolly  wi= ndows , that  every one uses  without  access  to the = ; source code ....mfsk with  fec  may of been a  more  fitt= ing  description .. but the  post  is history  as was/is&nbs= p; the  ensuing flap  ..

 

The = mode  deploys full  power to each tone  burst , ie  a mfsk, phase con= tinues   modulation scheme , the  average  power is  less=   than 100% peak  as the  system seems to  tx short = ms pulses ..may be  slightly  wrong  on that  , but  ga= ps do  appear causing my  carrier  led to  flicker &n= bsp;on tx

 

2) = bandwidth  is as advertised , the  ros -mf 1 & 7  is  approx&nb= sp; 98 Hz  wide  , coded to  fit  inside the  (new= ?) 100 Hz  data  allocation on 500 .. by inspection the  modul= ation seems to be  very  clean with  no  over  shoo= t  , unlike mfsk  that seems to  spread  quite  badly= ,  I note that  137K  band plans  talk of 200  hz data= bw

 

3) = Non linear  PA  is  required , the  smart x2  harmonic  amplifier= Gary and my self deployed gives a  work-round to the  logic  dri= ve  problem , Gary is  transverting to  137 khz  from HF wi= th a  linear  transverter ... however the  class d/e  amp  would  half  the  frequency  and = modulation , so  picking the  x2  harmonic  produced  a&= nbsp; drive  carrier of  274 khz , which then  reduced to&nbs= p; 137  at the  Ae  ......

 

4) Well&nb= sp; its a  free system ...... its  running  better  as time  go's= on and evolving , some  beacon modes are now  available , cut and&n= bsp; paste , and the  e-mail qsl seems to  work  nicely

 

5) = I  would  say it  already is , running  1 watt  to  my  Ae= I can  obtain 100%  decodes  from the  delft  web-sdr  on 500 Khz in mf-1 mode , 2 to 3  watts  for&n= bsp; mf-7 , that's  350  miles , on  7  meg  in qso wit= h  co2dc I have  taken 100% print  with  him running  250= mW to the  Ae   with  50 mW  drive to  my = ; Ae on 500 , print  was 100% in Harrogate, in tests  last  mon= th , Grays test on 137  as reported by F5WK , was under the visible&nb= sp; level  on the  spectrum  plot  , but  wa= s decoding.

 

1) facts= and  figures ..well  I don't  really know  .Mr Ros  has the&nbs= p; info  .. but its not  for  publication .... this is per= haps a sticky point .. but  while it  lasts  its showing what&= nbsp; can be  achieved  . wspr  is a  time  locked = ;  array  processed  system , using  best fit  matchi= ng  , ros  is a  free  running  live  data = system, that  is using  digital  noise  reduction / cancel= lation to  recover the  data and as  such  are  not  rea= lly  compatible , it  looks to be  on the lines of the  nois= e reduction  used in the  military satellite  systems&nbs= p; of the  1980/1990 .. but  in a much  reduced  bandwid= th, making use  of  modern  pc  power ... recepti= on of the  initial  sync  frame is  essential  ..  this&= nbsp; process  is  much  more robust than the  main data=   flow , but  dose  present a  problem  with = long  qsb   , unlike wspr that  is partitioned

 

From my ow= n experience  as was Michel , I have  seen  the  low  baud = rate  ros  system  produce  100% print  , when  the signal  could not  be  viewed on spec lab or  dete= cted by  headphones   .. so  I think 'we'  are  working  below the  noise , co2dc has  intimated that&n= bsp; the  system  provides a  increase of  20 dB over= the  psk31 system over the  path  co/vk , high  immunity&nbs= p; to  phase  distortion is also  provided  by the&nb= sp; modulation  system.

 

Ok Roger= , I hope that  fills in the  gaps ...  at the  moment you  still = need the  traditional  audio  to rf  translation = , however f5wk is  working  on a pic  system and the  x2&nbs= p; harmonic  amp  provides a  work  round  for&n= bsp; classe/d  amps  .. but  you  do  need = to  generate  on the intended  Ae frequency to  use the&nbs= p; amp.

 

73 - G ..=

 

Nb .. Ther= e may be  some  mileage   in using a  logic  gate  digital = mixer to  get on to  frequency ........ would need  a = x2  doubler (logic)   to  get over the  logic  drive&n= bsp; .. but if it works .. opens up  500/137 to  a lot  more da= ta  com's , bit of a  odd  concept . but if it  works .. ?<= /span>

 

 

 

 

Sent:= Sunday, June 20, 2010 9= :41 PM

Subject: Re: LF: Re: 137.500 kHz ROS beacon

 

Graham,

I'm behind on ROS progress so have a few questions please, if you've= time:

= 1.      How does ROS compare on a weak signal "effectiveness" factor with modes like QRSS3, 10 etc and wit= h WSPR? Is there a "dB better than" estimate for ROS in its various= forms?

= 2.      What sort of bandwidths does ROS occupy on= these LF tests? I appreciate it is spread spectrum, so there's not much power= at any time on any frequency.

= 3.      What sort of TX PA is needed - linear or non-linear?

= 4.      Is the software less clunky than when I lo= oked a few months back?

= 5.      Is it going to be a serious contender for= real QRP buffs like me?

73s
Roger G3XBM

On 20 June 2010 20:46, Graham <g8fzk@g8fzk.fsnet.co.uk> wrote:

''''for in= stance the French stn F5WK cannot hear you'''''

 

Well = , yes , that's the  point  of it  all  , no  noise, no  trace jus= t  100% pure  digital  data rolling over the  land , like= the  un-seen  fog  of  progress 

 

IARU - R-1= plan .. 137.4 to 137.6  digital modes , with the note that  CW is 'not allowe= d' 

 

I think th= e  test and  the  frequency  went fully  to  'to plan' and pave= s the way  for a magnitudinal  increase in  data  use on= 137 , to date limited by bandwidth  to  psk31 , ros-mf  by  design  occupying on 50%  of the  allowable  space= on  137  and 99% of the  100Hz  allocations  for = 500K. and  passing via  a  non linear  system , how = ; long will  it before the  first  live  data  qso&n= bsp; over the  pond ?

 

G .

 

 

 

From:= mal hamilton

Sent:= Sunday, June 20, 2010 6= :30 PM

Subject: Re: LF: Re: 137.500 kHz ROS beacon

 

Gary

There are= too many variables with these experiments for instance the French stn F5WK cannot hear yo= u but you are S5 solid on 137.5 here at my qth

The RX sta= tions antennas need to be analyised otherwise it misrepresents what you are doing.=

Can u pse= use frequencies below 136.5 kcs otherwise there is a problem with EU and Russian stations us= ing the area 137 - 137.778 kcs for QRS acty.

also this= is the DX window area for the USA and others.

73 de mal/= g3kev

 

 

 

----- Orig= inal Message -----

<= b>From: Gary - G4WGT

Sent: Sunda= y, June 20, 2010 4:31 PM

Subject: Re: LF: Re: 137.500 kHz ROS beacon

 

Hi Mal, <= /font>

 

Thank you for yo= ur report & comments. The mail you replied to gives all the details of equip= ment in use for the test beacon.

 

I would like to= be able to have a QSO using morse but I have to admit to a complete loss of co= nfidence as I have not used the mode for 25 years which was one year after I pa= ssed the test in 1984. Looking back, letting it go was a silly thing to do.

 

I do enjoy testi= ng out these "weak signal" modes & in the report I received fro= m Michel F5WK last night he wrote that he could not hear the signal or even see= it on SpecLab but he got a complete decode. So as a weak signal communicatio= n mode it works.

 

Just to elaborat= e on the antenna, it is a 12 metre base loaded vertical with a small elevated= inductor of 500uH at about 9 metres & a 1 x 3 metre capacity top with a 120= uH spiral inductor. In my small garden I have no space to go outwards only upwar= ds.

 

73,

 

Gary - G4WGT.

On 20 June 2010 13:48, mal hamilton <g3kevmal@talktalk.net> wrote:

Gary

If that wa= s you last nite on  137.5 kcs you were strong enough for cw or qrs3 no need to strugg= le with decodes from elswhere.

also I had= a qso with G3XIZ this morning on 137.0 kcs and got 599, he was 569.

Not sure= what antenna u were using but it was putting out a fair signal to this qth. Your radi= ators are probably acting as an antenna above earth.

 

de mal/g3k= ev

 

----- Orig= inal Message -----

<= b>From: Gary - G4WGT

Sent: Sunda= y, June 20, 2010 12:07 PM<= /font>

Subject: LF: 137.500 kHz ROS beacon

 

Hi LF,

Having suc= cessfully bench & on-air tested a x2 harmonic amplifier method of driving my G0MRF Class= D LF transmitter, I ran a beacon last night (Saturday 19th) on 137.500 kHz.=

 

An extract= from my previous e-mail description is shown at the end.

 

Using the= equipment & method described below, the ERP from my 12 metre vertical antenna was around= 150mW. The mode was ROS MF-1, 100 Hz bandwidth.

 

I received= the following report from Michel, F5WK in JN18HP, a distance of 410 miles (661 kilometres) in da= ylight.

 

>>= Not even a faint trace on a QRSS3 spectrum but:

>> RX1: 19:23= @ 5.9 Hz: 9 <STOP> -37 dB
>> RX1: 19:28= @ 5.4 Hz: O4WGT <STOP> -34 dB
>> RX1: 19:33= @ 5.4 Hz: G4WGT <STOP> -31 dB

 

The x2 har= monic low level amplifier is a simple way of driving a Class D type of transmitter which employs= a divide by 2 drive chain. My limitation with multi tone drive is that my DDS= VFO will only produce 2 frequencies ie. the main frequency & a CW/Rx offset= which has previously limited me to 2 tones as with RTTY & DFCW modes.

 

Please bea= r in mind that it will not be suitable for modes like PSK were tones are transmitted simultaneous= ly.

 

At the mom= ent the 2 small PCB's are precariously lying on the desk, when I have cased them I will publish= the circuit & pictures.

 

73<= /font>

 

Gary - G4W= GT.

**********= *************************************

After a fe= w days experimenting & bench testing a method of driving my
G0MRF Class D Tx on the 137.000 kHz band from my linear transverter I= finally
constructed a harmonic amplifier producing a 274.000 kHz signal from= 137.000
kHz input. An "on-air" trial was conducted resulting in a QS= O with
Graham G0NBD on 137.000 kHz using ROS data mode software.
 
My thanks to Graham for his ideas & tests.
 
The mode used was ROS MF-7. The equipment used for the QSO was as
follows. Kenwood TS-440 to my LF-MF linear transverter producing the 137.000 kHz signal, followed by a tuned harmonic circuit & buffer<= br> amplifier whose output was 274.000 kHz therefore at x2 drive for the= Class
D Tx. The x2 signal is then divided by the Tx driver chain in the
normal way to provide 137.000 kHz to the PA.
 
This method should also work well using WSPR & other similar modes= .

**********= ***********************************

 

 




--
http://g3xbm-qrp.blogspot.c= om/
http://www.g3xbm.co.uk
http://www.youtube.com/u= ser/g3xbm
G3XBM    GQRP 1678      ISWL G11088

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