Ok Andy
No problem , may be some one will take a look for you ?
you may need to drop to Op31 , but what ever the decode
you can work back over the min power req
GL -G.
--------------------------------------------------
From: "Andy Talbot" <[email protected]>
Sent: Tuesday, January 10, 2012 10:01 PM
To: <[email protected]>
Subject: Re: LF: opera 137 beacon going
No, the only Tx I have for LF these days is the 700 Watt job. Its
switch mode .
Changing taps may bring it down to 300 watts, but no less.
I'll have a look though the junk-junk box (stuff destined for rallies
/ dismantling etc) - may still have a QRP Tx from years gone by,
probably a 73kHz one that should go at 137
But it would be nice to be copied in the US using the QRO. Something
I'd never thought likely with this antenna ever before.
Andy
www.g4jnt.com
On 10 January 2012 21:21, Graham <[email protected]> wrote:
Opps
Spent so long on op2 , just realises your OP8
OP8 -32dB Op31 -38 dB S/N Mean (not peak) 21:07 136 G8IMR de G4WGT Op8
314
km -18 dB in Coppull, nr Preston
That is +20 dB over the s/n limit .. you should be ok down to 600
>>
60 >> .... 6 watts
Can you reduce to that level ?
G..300
--------------------------------------------------
From: "Andy Talbot" <[email protected]>
Sent: Tuesday, January 10, 2012 8:04 PM
To: <[email protected]>
Subject: Re: LF: opera 137 beacon going
600 Watt of Rf to 7m high Tee with Gnd loss about 80 ohms. I reckon
about -40dBi gain so call it a few tens of mW
Andy
On 10 January 2012 19:58, Graham <[email protected]> wrote:
Reaching Gary with +7 dB in hand , what is the carrier power ?
Be very interesting to see what the s/n would be from MAL
over similar range and similar path , with all that wire out
should be able to catch Andy's beacon into the +dB scale
G..
18:49 136 G8IMR de G4WGT Op8 314 km -19 dB in Coppull, nr Preston
--------------------------------------------------
From: "Andy Talbot" <[email protected]>
Sent: Tuesday, January 10, 2012 4:06 PM
To: <[email protected]>
Subject: LF: opera 137 beacon going
Having had to modify a 137kHz source to be able to generate on-off
keying, I'm transmitting a signal using 2.048s symbol mode on 137420Hz
33% duty cycle (for now)
This is based around my PIC generator for the mode
Details at http://www.g4jnt.com/PIC_Opera_Source.pdf and
http://www.g4jnt.com/OperaBeacon.zip
As its an independent source, with no PC in the Tx chain - no IP
packets will be sent to t'web showing the details
and its definitely gettign out....
15:46 136 G8IMR de F6CNI Op8 391 km -28 dB in 136 kHz dial nr Paris
Andy
G4JNT
|
