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Re: LF: Re: 137.500 kHz ROS beacon

To: <[email protected]>
Subject: Re: LF: Re: 137.500 kHz ROS beacon
From: "mal hamilton" <[email protected]>
Date: Mon, 21 Jun 2010 19:06:11 +0100
References: <[email protected]><002401cb1076$f4620140$0401a8c0@xphd97xgq27nyf> <[email protected]> <005b01cb109e$58400960$0401a8c0@xphd97xgq27nyf> <B2376F4FF57D42E6B49A39B05E1842B6@AGB> <001501cb1155$38cbbe00$0301a8c0@your91hoehfy9g> <2FE66D7AB59E43F3BDA1288BA86CC9D1@AGB>
Reply-to: [email protected]
Sender: [email protected]
Not RESRVED but a recommendation,  on amateur radio bands CW is permitted throughout the band wherea data modes and ssb are NOT
G3KEV
 
----- Original Message -----
From: Graham
Sent: Monday, June 21, 2010 5:17 PM
Subject: Re: LF: Re: 137.500 kHz ROS beacon

Scotch Mist  . no  just the  fog  of progress ... besides, the  frequency  slot  is  reserved  for  data  only  ,
 
So  there  is no  possibility of qrm , unless  the  reference is to key clicks ?

Sent: Monday, June 21, 2010 4:20 PM
Subject: Re: LF: Re: 137.500 kHz ROS beacon

So this mode is invisible, in that case I and other CW operators will not know it is there. No evasive action required to avoid QRM to it or the reverse.
Wonderful news
What I saw and heard the other night was Scotch Mist
g3kev
 
----- Original Message -----
From: Graham
Sent: Sunday, June 20, 2010 8:46 PM
Subject: Re: LF: Re: 137.500 kHz ROS beacon

''''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 .
 
 

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 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 -----
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 <[email protected]> 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 -----
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 <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 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.
    *********************************************





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