Return-Path: Received: from mtain-mh10.r1000.mx.aol.com (mtain-mh10.r1000.mx.aol.com [172.29.96.222]) by air-mf01.mail.aol.com (v129.4) with ESMTP id MAILINMF011-8bc94c1f8ff2b5; Mon, 21 Jun 2010 12:14:42 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-mh10.r1000.mx.aol.com (Internet Inbound) with ESMTP id 6B609380000BC; Mon, 21 Jun 2010 12:14:40 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1OQjcm-0006mH-Tr for rs_out_1@blacksheep.org; Mon, 21 Jun 2010 17:13:28 +0100 Received: from [83.244.159.144] (helo=relay3.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1OQjch-0006iN-Cr for rsgb_lf_group@blacksheep.org; Mon, 21 Jun 2010 17:13:23 +0100 Received: from smtp5.freeserve.com ([193.252.22.128]) by relay3.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1OQjce-00055Y-0e for rsgb_lf_group@blacksheep.org; Mon, 21 Jun 2010 17:13:22 +0100 Received: from me-wanadoo.net (localhost [127.0.0.1]) by mwinf3409.me.freeserve.com (SMTP Server) with ESMTP id 609EC1C00D2A for ; Mon, 21 Jun 2010 18:13:13 +0200 (CEST) Received: from me-wanadoo.net (localhost [127.0.0.1]) by mwinf3409.me.freeserve.com (SMTP Server) with ESMTP id 5BB451C008AE for ; Mon, 21 Jun 2010 18:13:13 +0200 (CEST) Received: from AGB (unknown [91.110.83.178]) by mwinf3409.me.freeserve.com (SMTP Server) with SMTP id C97561C00D2A for ; Mon, 21 Jun 2010 18:13:09 +0200 (CEST) X-ME-UUID: 20100621161309825.C97561C00D2A@mwinf3409.me.freeserve.com Message-ID: <93D7F8A99E224510A2F20FD5116299FC@AGB> From: "Graham" To: References: <000001cb1120$20c6b470$0202a8c0@laptopcore2> In-Reply-To: <000001cb1120$20c6b470$0202a8c0@laptopcore2> Date: Mon, 21 Jun 2010 17:13:09 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 14.0.8089.726 x-mimeole: Produced By Microsoft MimeOLE V14.0.8089.726 X-Antivirus: avast! (VPS 100621-0, 21/06/2010), Outbound message X-Antivirus-Status: Clean 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_0030_01CB1165.05945F50" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.4 required=5.0 tests=HTML_50_60, HTML_FONTCOLOR_UNKNOWN,HTML_MESSAGE,MISSING_OUTLOOK_NAME 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: 3039ac1d60de4c1f8ff00a5b X-AOL-IP: 193.82.116.20 ------=_NextPart_000_0030_01CB1165.05945F50 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hay .. go to chop the spikes somehow ! tech update .. the initial sync frame acquires lock , the noise= reduction follows ...and how ..... =20 G .. From: g3zjo=20 Sent: Monday, June 21, 2010 9:59 AM To: rsgb_lf_group@blacksheep.org=20 Subject: RE: LF: Re: 137.500 kHz ROS beacon 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@b= lacksheep.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=20 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 fo= r MF was , perhaps a bit of a unexpected out come from my initia= l 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 tab= le .. 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 ..=20 The mode deploys full power to each tone burst , ie a mfsk, phase= continues modulation scheme , the average power is less than 10= 0% peak as the system seems to tx short ms pulses ..may be slightl= y 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 allocati= on on 500 .. by inspection the modulation seems to be very clean wi= th no over shoot , unlike mfsk that seems to spread quite badl= y , I note that 137K band plans talk of 200 hz data bw=20 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 frequ= ency and modulation , so picking the x2 harmonic produced a dr= ive carrier of 274 khz , which then reduced to 137 at the Ae ..= ....=20 4) Well its a free system ...... its running better as time go's= on and evolving , some beacon modes are now available , cut and pa= ste , and the e-mail qsl seems to work nicely=20 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.=20 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 syste= ms of the 1980/1990 .. but in a much reduced bandwidth, making us= e 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 , unlik= e wspr that is partitioned=20 >From my own experience as was Michel , I have seen the low baud= rate ros system produce 100% print , when the signal could no= t 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 pro= vided by the modulation system.=20 Ok Roger , I hope that fills in the gaps ... at the moment you st= ill 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 generat= e on the intended Ae frequency to use the amp. 73 - G ..=20 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 . bu= t if it works .. ? From: Roger Lapthorn=20 Sent: Sunday, June 20, 2010 9:41 PM To: rsgb_lf_group@blacksheep.org=20 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 th= an" 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 ti= me on any frequency. 3. What sort of TX PA is needed - linear or non-linear?=20 4. Is the software less clunky than when I looked a few months ba= ck?=20 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 ju= st 100% pure digital data rolling over the land , like the un-see= n fog of progress =20 IARU - R-1 plan .. 137.4 to 137.6 digital modes , with the note that= CW is 'not allowed' =20 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 allo= cations for 500K. and passing via a non linear system , how lon= g will it before the first live data qso over the pond ? G .=20 From: mal hamilton=20 Sent: Sunday, June 20, 2010 6:30 PM To: rsgb_lf_group@blacksheep.org=20 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 misrepresen= ts 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 -----=20 From: Gary - G4WGT=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Sunday, June 20, 2010 4:31 PM Subject: Re: LF: Re: 137.500 kHz ROS beacon Hi Mal,=20 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 admi= t 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 bac= k, 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 verti= cal 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 sig= nal to this qth. Your radiators are probably acting as an antenna abov= e earth. de mal/g3kev ----- Original Message -----=20 From: Gary - G4WGT=20 To: LF Group (RSGB)=20 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 las= t 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 dis= tance 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 prod= uce 2 frequencies ie. the main frequency & a CW/Rx offset which has pr= eviously limited me to 2 tones as with RTTY & DFCW modes. Please bear in mind that it will not be suitable for modes like PS= K 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 transverte= r I finally constructed a harmonic amplifier producing a 274.000 kHz signal fr= om 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. =20 My thanks to Graham for his ideas & tests. =20 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. =20 This method should also work well using WSPR & other similar modes= . ********************************************* --=20 http://g3xbm-qrp.blogspot.com/ http://www.g3xbm.co.uk http://www.youtube.com/user/g3xbm G3XBM GQRP 1678 ISWL G11088 ------=_NextPart_000_0030_01CB1165.05945F50 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hay .. go to  chop the  spi= kes somehow=20 !
 
tech  update .. the  initia= l  =20 sync  frame acquires  lock , the  noise  reduction= follows=20 ...and how ..... 
 
G ..

From: g3zjo
Sent: Monday, June 21, 2010 9:59 AM
Subject: RE: LF: Re: 137.500 kHz ROS beacon

A little finger trouble from G=20 :-

 

<= FONT size=3D2 face=3DArial>3)      = =20 Non linear  PA  is&= nbsp;=20 required

 

He means:-

 

3) No= linear PA is=20 required

 

Eddie

 

-----Original=20 Message-----
From:= owner-rsgb_lf= _group@blacksheep.org=20 [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Graham
Sent: 21=20 June 2010 00:19=
To: rsgb_lf_group@blacksheep.org=
Subject: Re: LF:= Re: 137.500 kHz ROS=20 beacon

&nb= sp;

Ok Roge= r

&= nbsp;

Well&nb= sp; as you  will =20 of  noted Mr Ros had a  bit  of a  bumpy ride with=  =20 our  friends over  the  pond , so  having a = data =20 system  coded  for  MF was , perhaps a  bit = of a =20 unexpected out come  from my  initial  request , howeve= r ... we=20 have  one .....

&= nbsp;

2) Spre= ad  spectrum ..=20 well  that is where  it all  started to  fall apar= t=20 ......  yes the  term is  reasonably  close= , but =20 not  close enough to  fully  qualify , for  exampl= e F5WK=20 is  working on a  pic based translator  to  enable=  =20 a  dds  to be  driven  directly  from the&nbs= p;=20 ros  software ..  the  tx tones are  defined by&nb= sp;=20 a  look up  table .. not  exactly spread spectrum in th= e =20 military  sense ..yes there  is a  mixing  of = ;=20 digital  noise with the  tx data  stream , but  as= =20 everyone  is using the  same  prog free , then  it= s=20 not  particularly secret ...unlike  say  jolly  wi= ndows ,=20 that  every one uses  without  access  to the = ; source=20 code ....mfsk with  fec  may of been a  more  fitt= ing =20 description .. but the  post  is history  as was/is&nbs= p;=20 the  ensuing flap  ..

&= nbsp;

The&nbs= p; mode  deploys=20 full  power to each tone  burst , ie  a mfsk, phase con= tinues=20   modulation scheme , the  average  power is  less=  =20 than 100% peak  as the  system seems to  tx short = ms pulses=20 ..may be  slightly  wrong  on that  , but  ga= ps=20 do  appear causing my  carrier  led to  flicker &n= bsp;on=20 tx

&= nbsp;

2) = ; bandwidth  is as=20 advertised , the  ros -mf 1 & 7  is  approx&nb= sp; 98=20 Hz  wide  , coded to  fit  inside the  (new= ?) 100=20 Hz  data  allocation on 500 .. by inspection the  modul= ation=20 seems to be  very  clean with  no  over  shoo= t  ,=20 unlike mfsk  that seems to  spread  quite  badly= ,  I=20 note that  137K  band plans  talk of 200  hz data= bw=20

&= nbsp;

3) = ; Non linear  PA =20 is  required , the  smart x2  harmonic  amplifier= Gary and=20 my self deployed gives a  work-round to the  logic  dri= ve =20 problem , Gary is  transverting to  137 khz  from HF wi= th a =20 linear  transverter ... however the  class d/e  amp&nbs= p;=20 would  half  the  frequency  and  modulation= , so =20 picking the  x2  harmonic  produced  a  drive=  =20 carrier of  274 khz , which then  reduced to  137 = at=20 the  Ae  ......

&= nbsp;

4) Well=   its a  free=20 system ...... its  running  better  as time  go's= on and=20 evolving , some  beacon modes are now  available , cut and&n= bsp; paste=20 , and the  e-mail qsl seems to  work  nicely=20

&= nbsp;

5) = ; I  would  say=20 it  already is , running  1 watt  to  my  Ae= I=20 can  obtain 100%  decodes  from the  delft = =20 web-sdr  on 500 Khz in mf-1 mode , 2 to 3  watts  for&n= bsp; mf-7=20 , that's  350  miles , on  7  meg  in qso wit= h=20  co2dc I have  taken 100% print  with  him running=   250=20 mW to the  Ae   with  50 mW  drive to = my  Ae=20 on 500 , print  was 100% in Harrogate, in tests  last = month ,=20 Grays test on 137  as reported by F5WK , was under the visible&nb= sp;=20 level  on the  spectrum  plot  , but  wa= s=20 decoding.

&= nbsp;

1) fact= s and  figures=20 ..well  I don't  really know  .Mr Ros  has the&nbs= p;=20 info  .. but its not  for  publication .... this is per= haps a=20 sticky point .. but  while it  lasts  its showing what&= nbsp; can=20 be  achieved  . wspr  is a  time  locked = ; =20 array  processed  system , using  best fit  matchi= ng  ,=20 ros  is a  free  running  live  data  sy= stem,=20 that  is using  digital  noise  reduction / cancel= lation=20 to  recover the  data and as  such  are  not&= nbsp;=20 really  compatible , it  looks to be  on the lines of= the =20 noise reduction  used in the  military satellite  syste= ms =20 of the  1980/1990 .. but  in a much  reduced  band= width,=20 making use  of  modern  pc  power ... recepti= on of=20 the  initial  sync  frame is  essential  ..&n= bsp;=20 this  process  is  much  more robust than the = ; main=20 data  flow , but  dose  present a  problem = with =20 long  qsb   , unlike wspr that  is partitioned=20

&= nbsp;

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

&= nbsp;

Ok Roge= r , I hope that  fills=20 in the  gaps ...  at the  moment you  still = need=20 the  traditional  audio  to rf  translation = , however=20 f5wk is  working  on a pic  system and the  x2&nbs= p;=20 harmonic  amp  provides a  work  round  for&n= bsp;=20 classe/d  amps  .. but  you  do  need = to =20 generate  on the intended  Ae frequency to  use the&nbs= p;=20 amp.

&= nbsp;

73 - G= ..

&= nbsp;

Nb ..= There may be  some =20 mileage   in using a  logic  gate  digital = mixer=20 to  get on to  frequency ........ would need  a = x2 =20 doubler (logic)   to  get over the  logic  drive&n= bsp; ..=20 but if it works .. opens up  500/137 to  a lot  more da= ta =20 com's , bit of a  odd  concept . but if it  works ..=20 ?

&= nbsp;

&= nbsp;

&= nbsp;

&= nbsp;

From: Roger Lapt= horn=20

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

Subject: Re: LF:=20 Re: 137.500 kHz ROS beacon

&= nbsp;

Graham,

I'= m behind=20 on ROS progress so have a few questions please, if you've=20 time:

<= FONT size=3D3 face=3D"Times New Roman">1.     =20 How does ROS compare on a weak signal=20 "effectiveness" factor with modes like QRSS3, 10 etc and with WSPR? Is= there a=20 "dB better than" estimate for ROS in its various forms?

<= FONT size=3D3 face=3D"Times New Roman">2.     =20 What sort of bandwidths does ROS occupy on= these LF=20 tests? I appreciate it is spread spectrum, so there's not much power= at any time=20 on any frequency.

<= FONT size=3D3 face=3D"Times New Roman">3.     =20 What sort of TX PA is needed - linear or= non-linear?=20

<= FONT size=3D3 face=3D"Times New Roman">4.     =20 Is the software less clunky than when I lo= oked a few=20 months back?

<= FONT size=3D3 face=3D"Times New Roman">5.     =20 Is it going to be a serious contender for= real QRP=20 buffs like me?

73s
Roger G3XBM

On = 20 June=20 2010 20:46, Graham <g8= fzk@g8fzk.fsnet.co.uk> wrote:

''''for= instance the French stn=20 F5WK cannot hear you'''''

&= nbsp;

Well&nb= sp; , yes , that's the =20 point  of it  all  , no  noise, no  trace jus= t =20 100% pure  digital  data rolling over the  land , like= the =20 un-seen  fog  of  progress 

&= nbsp;

IARU -= R-1 plan .. 137.4 to=20 137.6  digital modes , with the note that  CW is 'not allowe= d' =20

&= nbsp;

I think= the  test and =20 the  frequency  went fully  to  'to plan' and pave= s the=20 way  for a magnitudinal  increase in  data  use on= 137 , to=20 date limited by bandwidth  to  psk31 , ros-mf  by = =20 design  occupying on 50%  of the  allowable  space= on =20 137  and 99% of the  100Hz  allocations  for = 500K.=20 and  passing via  a  non linear  system , how = ; long=20 will  it before the  first  live  data  qso&n= bsp; over=20 the  pond ?

&= nbsp;

G .

&= nbsp;

&= nbsp;

 

From: mal hamilton=20

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

Subject: Re: LF:=20 Re: 137.500 kHz ROS beacon

&= nbsp;

Gary

There= are too many variables with=20 these experiments for instance the French stn F5WK cannot hear yo= u but you=20 are S5 solid on 137.5 here at my qth

The RX= stations antennas need to be=20 analyised otherwise it misrepresents what you are doing.=

Can u= pse use frequencies below=20 136.5 kcs otherwise there is a problem with EU and Russian stations us= ing the=20 area 137 - 137.778 kcs for QRS acty.

also th= is is the DX window area for=20 the USA and=20 others.

73 de= =20 mal/g3kev

&= nbsp;

&= nbsp;

&= nbsp;

-----= Original Message -----=20

Sent:=20 Sunday, June 20,=20 2010 4:31=20 PM

Subject: Re: LF:= =20 Re: 137.500 kHz ROS beacon

=  

Hi Mal,=20

=  

Thank you= for your report=20 & comments. The mail you replied to gives all the details of equ= ipment in=20 use for the test beacon.

=  

I would lik= e to be able=20 to have a QSO using morse but I have to admit to a complete loss of= confidence=20 as I have not used the mode for 25 years which was one year after I= passed the=20 test in 1984. Looking back, letting it go was a silly thing to=20 do.

=  

I do enjoy= testing out=20 these "weak signal" modes & in the report I received from Michel= F5WK last=20 night he wrote that he could not hear the signal or even see it on= SpecLab but=20 he got a complete decode. So as a weak signal communication mode it= =20 works.

=  

Just to ela= borate on the=20 antenna, it is a 12 metre base loaded vertical with a small elevated= inductor=20 of 500uH at about 9 metres & a 1 x 3 metre capacity top with a= 120uH=20 spiral inductor. In my small garden I have no space to go outwards= only=20 upwards.

=  

73,

=  

Gary - G4WGT.

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

Gary<= /SPAN>

If th= at was you last nite on =20 137.5 kcs you were strong enough for cw or qrs3 no need to stru= ggle with=20 decodes from elswhere.

also= I had a qso with G3XIZ this=20 morning on 137.0 kcs and got 599, he was 569.

Not= sure what antenna u were=20 using but it was putting out a fair signal to this qth. Your ra= diators=20 are probably acting as an antenna above earth.

=  

de=20 mal/g3kev

=  

-= ---- Original Message -----=20

From: Gary - G4WGT

To: LF Group (RSGB)=20

Sent:=20 Sunday, June 20,=20 2010 12:07=20 PM

Subject:= LF:=20 137.500 kHz ROS beacon

<= /SPAN> 

H= i LF,

H= aving successfully bench &=20 on-air tested a x2 harmonic amplifier method of driving my G0MRF= Class D LF=20 transmitter, I ran a beacon last night (Saturday 19th) on 137.500= =20 kHz.

<= /SPAN> 

A= n extract from my previous=20 e-mail description is shown at the end.

<= /SPAN> 

U= sing the equipment & method=20 described below, the ERP from my 12 metre vertical antenna was aro= und 150mW.=20 The mode was ROS MF-1, 100 Hz bandwidth.

<= /SPAN> 

I= received the following report=20 from Michel, F5WK in JN18HP, a distance of 410 miles (661 kilometr= es) in=20 daylight.

<= /SPAN> 

&= gt;> Not even a faint trace=20 on a QRSS3 spectrum but:

>> RX1: 19:23 @ 5.9 Hz: 9=20 <STOP> -37 dB
>> RX1: 19:28 @ 5.4 Hz:=20 O4WGT <STOP> -34 dB
>> RX1: 19:33 @ 5.4 Hz:=20 G4WGT <STOP> -31 dB

<= /SPAN> 

T= he x2 harmonic low level=20 amplifier is a simple way of driving a Class D type of transmitter= which=20 employs a divide by 2 drive chain. My limitation with multi tone= drive is=20 that my DDS VFO will only produce 2 frequencies ie. the main frequ= ency &=20 a CW/Rx offset which has previously limited me to 2 tones as with= RTTY &=20 DFCW modes.

<= /SPAN> 

P= lease bear in mind that it will=20 not be suitable for modes like PSK were tones are transmitted=20 simultaneously.

<= /SPAN> 

A= t the moment the 2 small PCB's=20 are precariously lying on the desk, when I have cased them I will= publish=20 the circuit & pictures.

<= /SPAN> 

7= 3

<= /SPAN> 

G= ary -=20 G4WGT.

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

A= fter a few days experimenting=20 & bench testing a method of driving my
G0MRF Class D Tx on= the=20 137.000 kHz band from my linear transverter I finally
construct= ed a=20 harmonic amplifier producing a 274.000 kHz signal from 137.000
= kHz input.=20 An "on-air" trial was conducted resulting in a QSO with
Graham= G0NBD on=20 137.000 kHz using ROS data mode software.
 
My thanks= to Graham=20 for his ideas & tests.
 
The mode used was ROS MF-7= . The=20 equipment used for the QSO was as
follows. Kenwood TS-440 to my= LF-MF=20 linear transverter producing the
137.000 kHz signal, followed= by a tuned=20 harmonic circuit & buffer
amplifier whose output was 274.00= 0 kHz=20 therefore at x2 drive for the Class
D Tx. The x2 signal is then= divided=20 by the Tx driver chain in the
normal way to provide 137.000 kHz= to the=20 PA.
 
This method should also work well using WSPR &= ; other=20 similar modes.

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

=  

 

<= /DIV>




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G3XBM=20    GQRP 1678      ISWL=20 G11088



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