Return-Path: Received: from mtain-dd06.r1000.mx.aol.com (mtain-dd06.r1000.mx.aol.com [172.29.64.146]) by air-mc02.mail.aol.com (v129.4) with ESMTP id MAILINMC024-a8d64c1f1769b3; Mon, 21 Jun 2010 03:40:26 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-dd06.r1000.mx.aol.com (Internet Inbound) with ESMTP id D9220380000BD; Mon, 21 Jun 2010 03:40:19 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1OQbbE-00070v-CO for rs_out_1@blacksheep.org; Mon, 21 Jun 2010 08:39:20 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1OQbbC-00070Z-P0 for rsgb_lf_group@blacksheep.org; Mon, 21 Jun 2010 08:39:18 +0100 Received: from mail-bw0-f43.google.com ([209.85.214.43]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1OQbb9-0004No-Lg for rsgb_lf_group@blacksheep.org; Mon, 21 Jun 2010 08:39:18 +0100 Received: by bwz19 with SMTP id 19so1022057bwz.16 for ; Mon, 21 Jun 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<1A277397AD72498D97B7D9CD2F7B3CA5@AGB> References: <002401cb1076$f4620140$0401a8c0@xphd97xgq27nyf> <005b01cb109e$58400960$0401a8c0@xphd97xgq27nyf> <1A277397AD72498D97B7D9CD2F7B3CA5@AGB> Date: Mon, 21 Jun 2010 08:39:11 +0100 Message-ID: From: Roger Lapthorn To: rsgb_lf_group@blacksheep.org DomainKey-Status: good (testing) 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=0016e6d7e0939bdccb04898566ef X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.5 required=5.0 tests=HTML_20_30,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-SCOLL-AUTHENTICATION: mail_rly_antispam_dkim-m253.1 ; domain : gmail.com DKIM : pass x-aol-sid: 3039ac1d40924c1f17635901 X-AOL-IP: 193.82.116.20 X-Mailer: Unknown (No Version) --0016e6d7e0939bdccb04898566ef Content-Type: text/plain; charset=ISO-8859-1 Graham, Thank you for taking the time and trouble to give me (and others here) a very full and helpful response to my questions about ROS. 73s Roger G3XBM On 21 June 2010 00:18, Graham wrote: > 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 > > > -- http://g3xbm-qrp.blogspot.com/ http://www.g3xbm.co.uk http://www.youtube.com/user/g3xbm G3XBM GQRP 1678 ISWL G11088 --0016e6d7e0939bdccb04898566ef Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Graham,

Thank you for taking the time and trouble to give me (and= others here) a very full and helpful response to my questions about ROS.<= br>
73s
Roger G3XBM

On 21 June 201= 0 00:18, Graham <g8fzk@g8fzk.fsnet.co.uk> wrote:
Ok Roger
=A0
Well=A0 as you=A0 will=A0 of=A0 noted= =20 Mr Ros had a=A0 bit=A0 of a=A0 bumpy ride with=A0 our=A0 friends=20 over=A0 the=A0 pond , so=A0 having a=A0 data=A0 system=A0=20 coded=A0 for=A0 MF was , perhaps a=A0 bit=A0 of a=A0 unexpected=20 out come=A0 from my=A0 initial=A0 request , however ... we have=A0=20 one .....
=A0
2) Spread=A0 spectrum .. well=A0 that= is=20 where=A0 it all=A0 started to=A0 fall apart ......=A0 yes the=A0=20 term is=A0=A0reasonably =A0close , but=A0 not=A0 close enough=20 to=A0 fully=A0 qualify , for=A0 example F5WK is=A0 working on=20 a=A0 pic based translator=A0 to=A0 enable=A0 a=A0 dds=A0 to=20 be=A0 driven=A0 directly=A0 from the=A0 ros=A0 software ..=A0=20 the=A0 tx tones are=A0 defined by=A0 a=A0 look up=A0 table ..=20 not=A0 exactly spread spectrum in the=A0 military=A0 sense ..yes=20 there=A0 is a=A0 mixing=A0 of=A0 digital=A0 noise with the=A0=20 tx data=A0 stream , but=A0 as everyone=A0 is using the=A0 same=A0=20 prog free , then=A0 its not=A0 particularly secret ...unlike=A0=20 say=A0 jolly=A0 windows , that=A0 every one uses=A0 without=A0=20 access=A0 to the=A0 source code ....mfsk with=A0 fec=A0 may of been=20 a=A0 more=A0 fitting=A0 description .. but the=A0 post=A0 is=20 history=A0 as was/is=A0 the=A0 ensuing flap=A0 ..
=A0
The=A0 mode=A0 deploys full=A0 power= to=20 each tone=A0 burst , ie=A0 a mfsk, phase continues =A0 modulation=20 scheme , the=A0 average=A0 power is=A0 less=A0 than 100% peak=A0=20 as the=A0 system seems to=A0 tx short=A0ms pulses ..may be=A0=20 slightly=A0 wrong=A0 on that=A0 , but=A0 gaps do=A0 appear=20 causing my=A0 carrier=A0 led to=A0 flicker =A0on tx
=A0
2)=A0 bandwidth=A0 is as advertised= ,=20 the=A0 ros -mf=A01 & 7 =A0is=A0 approx=A0 98 Hz=A0=20 wide=A0 , coded to=A0 fit=A0 inside the=A0 (new ?) 100 Hz=A0=20 data=A0 allocation on 500 .. by inspection the=A0 modulation seems to=20 be=A0 very=A0 clean with=A0 no=A0 over=A0 shoot=A0 , unlike=20 mfsk=A0 that seems to=A0 spread=A0 quite=A0 badly ,=A0 I note=20 that=A0 137K=A0 band plans=A0 talk of 200=A0 hz data bw=20
=A0
3)=A0 Non linear=A0 PA=A0 is=A0=20 required , the=A0 smart x2=A0 harmonic=A0 amplifier Gary and my self=20 deployed gives a=A0 work-round to the=A0 logic=A0 drive=A0 problem ,=20 Gary is=A0 transverting to=A0 137 khz=A0 from HF with a=A0=20 linear=A0 transverter ... however the=A0 class d/e=A0 amp=A0=20 would=A0 half=A0 the=A0 frequency=A0 and=A0 modulation , so=A0=20 picking the=A0 x2=A0 harmonic=A0 produced=A0 a=A0 drive=A0=20 carrier of=A0 274 khz , which then=A0 reduced to=A0 137=A0 at=20 the=A0 Ae=A0 ......
=A0
4) Well=A0 its a=A0 free system .....= .=20 its=A0 running=A0 better=A0 as time=A0 go's on and evolving ,=20 some=A0 beacon modes are now=A0 available , cut and=A0 paste , and=20 the=A0 e-mail qsl seems to=A0 work=A0 nicely
=A0
5)=A0 I=A0 would=A0 say it=A0 already= =20 is , running=A0 1 watt=A0 to=A0 my=A0 Ae I can=A0 obtain=20 100%=A0 decodes=A0 from the=A0 delft=A0 web-sdr=A0 on 500 Khz in=20 mf-1 mode , 2 to 3=A0 watts=A0 for=A0 mf-7 , that's=A0 350=A0=20 miles , on=A0 7=A0 meg=A0 in qso with =A0co2dc I have=A0 taken=20 100% print=A0 with=A0 him running=A0 250 mW to the=A0 Ae=A0=A0=20 with=A0 50 mW=A0 drive to=A0 my=A0 Ae on 500 , print=A0 was 100%=20 in Harrogate, in tests=A0 last=A0 month , Grays test on 137=A0 as=20 reported by F5WK , was under the visible=A0 level=A0 on the=A0=20 spectrum=A0 plot=A0=A0, but=A0 was decoding.
=A0
1) facts and=A0 figures ..well=A0 I= =20 don't=A0 really know=A0 .Mr Ros=A0 has the=A0 info=A0 .. but its=20 not=A0 for=A0 publication .... this is perhaps a sticky point .. but=A0=20 while it=A0 lasts=A0 its showing what=A0 can be=A0 achieved =A0.=20 wspr=A0 is a=A0 time=A0 locked=A0=A0 array=A0 processed=A0=20 system , using=A0 best fit=A0 matching=A0 , ros=A0 is a=A0=20 free=A0 running=A0 live=A0 data=A0 system, that=A0 is using=A0=20 digital=A0 noise=A0 reduction / cancellation to=A0 recover the=A0=20 data and as=A0 such=A0 are=A0 not=A0 really=A0 compatible ,=20 it=A0 looks to be=A0 on the lines of the=A0 noise reduction=A0 used=20 in the=A0 military satellite=A0 systems=A0 of the=A0 1980/1990 ..=20 but=A0 in a much=A0 reduced=A0 bandwidth, making use=A0 of=A0=20 modern=A0 pc=A0 power ...=A0reception of the=A0 initial=A0=20 sync=A0 frame is=A0 essential=A0 ..=A0 this=A0 process=A0=20 is=A0 much=A0 more robust than the=A0 main data=A0 flow , but=A0=20 dose=A0 present a=A0 problem=A0 with=A0 long=A0 qsb =A0 ,=20 unlike wspr that=A0 is partitioned
=A0
From my own experience=A0 as was Mich= el , I=20 have=A0 seen=A0=A0the=A0 low=A0 baud=A0 rate=A0 ros=A0=20 system=A0 produce=A0 100% print=A0 , when=A0 the signal=A0 could=20 not=A0 be=A0 viewed on spec lab or=A0 detected by=A0 headphones=20 =A0 .. so=A0 I think 'we'=A0 are=A0 working=A0 below the=A0=20 noise , co2dc has=A0 intimated that=A0 the=A0 system=A0 provides=20 a=A0 increase of =A020 dB over the=A0 psk31 system over the=A0=20 path=A0 co/vk , high=A0 immunity=A0 to=A0 phase=A0 distortion is=20 also=A0 provided=A0 by the=A0 modulation=A0 system.
=A0
Ok Roger , I hope that=A0 fills in th= e=A0=20 gaps ...=A0 at the=A0 moment you=A0 still=A0 need the=A0=20 traditional=A0 audio=A0 to rf=A0 translation=A0 , however f5wk=20 is=A0 working=A0 on a pic=A0 system and the=A0 x2=A0=20 harmonic=A0 amp=A0 provides a=A0 work=A0 round=A0 for=A0=20 classe/d=A0 amps=A0 .. but=A0 you=A0 do=A0 need=A0 to=A0=20 generate=A0 on the intended=A0 Ae frequency to=A0 use the=A0=20 amp.
=A0
73 - G ..
=A0
Nb .. There may be=A0 some=A0 mileage= =A0=20 in using a=A0 logic=A0 gate=A0 digital=A0 mixer to=A0 get on=20 to=A0 frequency ........ would need=A0 a=A0 x2=A0 doubler (logic)=20 =A0 to=A0 get over the=A0 logic=A0 drive=A0 .. but if it works ..=20 opens up=A0 500/137 to=A0 a lot=A0 more data=A0 com's , bit of=20 a=A0 odd=A0 concept . but if it=A0 works .. ?
=A0
=A0
=A0

Sent: Sunday, June 20, 2010 9:41 PM
Subject: Re: LF: Re: 137.500 kHz ROS beacon
<= /div>

Graham,

I'm behind on ROS progress so have a few= questions=20 please, if you've time:
  1. How does ROS compare on a weak signal "effectiveness" fact= or with modes=20 like QRSS3, 10 etc and with WSPR? Is there a "dB better than"= estimate for ROS=20 in its various forms?
  2. What sort of bandwidths does ROS occupy on these LF tests? I ap= preciate it=20 is spread spectrum, so there's not much power at any time on any=20 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 bac= k?=20
  5. Is it going to be a serious contender for real QRP buffs like= =20 me?
73s
Roger G3XBM

On 20 June 2010 20:46, Graham <g8fzk@g8= fzk.fsnet.co.uk>=20 wrote:
''''for instance th= e French stn F5WK=A0cannot=20 hear you'''''
=A0
Well=A0 , yes , that's the=A0= point=A0=20 of it=A0 all=A0 , no=A0 noise, no=A0 trace just=A0 100%=20 pure=A0 digital=A0 data rolling over the=A0 land , like the=A0=20 un-seen=A0 fog=A0 of=A0 progress=A0
=A0
IARU - R-1 plan .. 137.4 to 137.6= =A0 digital=20 modes , with the note that=A0 CW is 'not allowed'=A0
=A0
I think the=A0 test and=A0 the=A0= =20 frequency=A0 went fully=A0 to =A0'to plan' and paves the way=A0= =20 for a magnitudinal=A0 increase in=A0 data=A0 use on 137 , to date=20 limited by bandwidth =A0to=A0 psk31 , ros-mf=A0 by=A0 design=A0=20 occupying on 50%=A0 of the=A0 allowable=A0 space on=A0 137=A0=20 and 99% of the=A0 100Hz=A0 allocations=A0 for=A0 500K. and=A0=20 passing via=A0 a=A0 non linear=A0 system , how=A0 long will=A0=20 it before the=A0 first=A0 live=A0 data=A0 qso=A0 over the=A0=20 pond ?
=A0
G .
=A0
=A0

Sent: Sunday, June 20, 2010 6:30 PM
Subject: Re: LF: Re: 137.500 kHz ROS=20 beacon

Gary
There are too many variables with= these=20 experiments for instance the French stn F5WK=A0cannot hear you but you= are=20 S5 solid on=A0137.5=A0here at my qth
The RX stations antennas need to be= analyised=20 otherwise it misrepresents what you are doing.
Can u pse use frequencies below 136= .5 kcs=20 otherwise there is a problem with EU and Russian stations using the area= 137 -=20 137.778 kcs for QRS acty.
also this is the DX window area for= the USA and=20 others.
73 de mal/g3kev
=A0
=A0
=A0
----- Original Message -----
Sent: Sunday, June 20, 2010 4:= 31=20 PM
Subject: Re: LF: Re: 137.500= kHz ROS=20 beacon

Hi Mal,=20

Thank you for your report & comments. The mail you replied to= gives=20 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=20 to a complete loss of confidence as I have not used the mode for 25 ye= ars=20 which was one year after I passed the test in 1984. Looking back, lett= ing it=20 go was a silly thing to do.

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

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

73,

Gary - G4WGT.

On 20 June 2010 13:48, mal hamilton <g3kevmal@talktalk.net> wrote:
Gary
If that was you last nite on=A0= 137.5 kcs=20 you were strong enough for cw or qrs3=A0no need to struggle with=20 decodes from elswhere.
also I had a qso with G3XIZ thi= s morning on=20 137.0 kcs and got 599, he was 569.
Not sure what antenna u were us= ing=A0but=20 it was putting out a fair signal to this qth. Your radiators are pro= bably=20 acting as an antenna above earth.
=A0
de mal/g3kev
=A0
----- Original Message -----
From:=20 Gary - G4WGT
Sent: Sunday, June 20, 201= 0 12:07=20 PM
Subject: LF: 137.500 kHz= ROS=20 beacon

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

An extract from my previous e-mail description is shown at th= e=20 end.

Using the equipment & method described below, the ERP fro= m my=20 12 metre vertical antenna was around 150mW. The mode was ROS MF-1,= 100=20 Hz bandwidth.

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

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

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

The x2 harmonic low level amplifier is a simple way of drivin= g a=20 Class D type of transmitter which employs a divide by 2 drive chai= n. My=20 limitation with multi tone drive is that my DDS VFO will only prod= uce 2=20 frequencies ie. the main frequency & a CW/Rx offset which has= =20 previously limited me to 2 tones as with RTTY & DFCW modes.

Please bear in mind that it will not be suitable for modes li= ke PSK=20 were tones are transmitted simultaneously.

At the moment the 2 small PCB's are precariously lying on= the desk,=20 when I have cased them I will publish the circuit & pictures.<= /div>

73

Gary - G4WGT.
    ***********************************************
    After a few days experimenting & bench testing a method of= =20 driving my
    G0MRF Class D Tx on the 137.000 kHz band from my= linear=20 transverter I finally
    constructed a harmonic amplifier produc= ing a=20 274.000 kHz signal from 137.000
    kHz input. An "on-air&qu= ot; trial was=20 conducted resulting in a QSO with
    Graham G0NBD on 137.000 kHz= using=20 ROS data mode software.
    =A0
    My thanks to Graham for his id= eas=20 & tests.
    =A0
    The mode used was ROS MF-7. The equipment= =20 used for the QSO was as
    follows. Kenwood TS-440 to my LF-MF= linear=20 transverter producing the
    137.000 kHz signal, followed by a= tuned=20 harmonic circuit & buffer
    amplifier whose output was 274.= 000=20 kHz therefore at x2 drive for the Class
    D Tx. The x2 signal= is then=20 divided by the Tx driver chain in the
    normal way to provide= 137.000=20 kHz to the PA.
    =A0
    This method should also work well using= =20 WSPR & other similar modes.
    *********************************************






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