Re: LF: OPERA Question

[M0FMT <m0fmt@yahoo.co.uk>]

Hi all

 

I think Stefan is going to direct key the TX ON/OFF from the Serial Port or he is doing it from a PIC type keyer (like me) or he has just recorded the output from the PC SC onto an MP3 player and using the ON/OFF tone on a continuous loop to key a relay transistor via a sound detector cct thence to key the TX. All options are possible this is the good bit about this type of weak signal communication.

 

The RX window is 1.6 / 1.8kc/s from the TX carrier on an SSB TX (Upper Side Band) but when using a CW rig the carrier has to be with in the window on the EU 600m band it is currently 478.6 / 478.8kc/s on the UK  600m band it is currently 501.6 / 501.8kc/s.

 

So long as the RX is set such that it hears a tone 1.6 to 1.7kc/s and that it is connected to the PC Sound Card input at the right level then it will decode. So if you use a Direct Convertion  RX it doesn't matter which way you approach the signal either upper or lower side band.

73 es GL Pete M0FMT IO91UX

From: Albert <westberg@xs4all.nl>
To: rsgb_lf_group@blacksheep.org
Sent: Tuesday, 10 July 2012, 14:58
Subject: Re: LF: OPERA Question

Stefan,

Download the Opera program. In the waterfall you will see two red lines, put the cursor on the lines and read the frequency (upper left window of the waterfall display)  Op4 differs from Op8 etc a frequency within this band is the input of the USB TX so 477kHz + (a frequency between the red lines). When using CAT control Opera will choose a not occupied freq. in the appropriate pass band.

73, Albert