Discussion:
Obviating the high noise levels on MF & HF?
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Gareth's Downstairs Computer
2017-06-15 18:30:31 UTC
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I wonder if we all could work together to conceive of a scheme
to obviate the high noise levels on Mf & HF?

Perhaps phase locking the modulation to the signals
received from GPS?

Agreed, this moves away from the simplistic approaches
that are the essence of _REAL_ amateur / ham radio by
making use of the constellation of the GPS satellites
whose system complexity is way beyond anything that
we might construct.
Iain Young, G7III
2017-06-18 19:12:06 UTC
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Post by Gareth's Downstairs Computer
I wonder if we all could work together to conceive of a scheme
to obviate the high noise levels on Mf & HF?
First things first, define the objective. You are not going to
_ever_ get rid of _all_ noise. What is your required throughput ?
What bandwidth are you planning to use ?
Post by Gareth's Downstairs Computer
Perhaps phase locking the modulation to the signals
received from GPS?
You mean have your transmitter and receiver locked to a
GPSDO ?

I do that on a daily basis. What GPSDO were you thinking
of using ? I can offer advice here, having 3xHP GPSDO's,
1xLucent GPSRb [Rubidium], 2 free running Rubidiums, and
4 LORAN receivers.

ISTR claiming that a BC221 was more than sufficient for
your purposes. In the same thread, Did you not ask how my LORAN
receiver is doing what it is supposed to be doing ?

What are you trying to achieve here ? That the TX and (Remote)
RX are on the same frequency so you can use very tight filters
in software on the RX end ? Or ?


And what modulation were you thinking ? There are digital
schemes (that can be used for digital voice) that might meet
your requirements, without a GPSDO (Although I would always
suggest and advise one) Are we just talking SSB or CW ?
Post by Gareth's Downstairs Computer
Agreed, this moves away from the simplistic approaches
that are the essence of _REAL_ amateur / ham radio by
making use of the constellation of the GPS satellites
whose system complexity is way beyond anything that
we might construct.
I think G3RUH, and G4JNT (amongst others) would disagree with
you. They have both done "Ground Segments" for the GPS System.


73's

Iain
Brian Reay
2017-06-19 08:15:42 UTC
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Post by Iain Young, G7III
Post by Gareth's Downstairs Computer
I wonder if we all could work together to conceive of a scheme
to obviate the high noise levels on Mf & HF?
First things first, define the objective. You are not going to
_ever_ get rid of _all_ noise. What is your required throughput ?
What bandwidth are you planning to use ?
Post by Gareth's Downstairs Computer
Perhaps phase locking the modulation to the signals
received from GPS?
You mean have your transmitter and receiver locked to a
GPSDO ?
I do that on a daily basis. What GPSDO were you thinking
of using ? I can offer advice here, having 3xHP GPSDO's,
1xLucent GPSRb [Rubidium], 2 free running Rubidiums, and
4 LORAN receivers.
ISTR claiming that a BC221 was more than sufficient for
your purposes. In the same thread, Did you not ask how my LORAN
receiver is doing what it is supposed to be doing ?
What are you trying to achieve here ? That the TX and (Remote)
RX are on the same frequency so you can use very tight filters
in software on the RX end ? Or ?
And what modulation were you thinking ? There are digital
schemes (that can be used for digital voice) that might meet
your requirements, without a GPSDO (Although I would always
suggest and advise one) Are we just talking SSB or CW ?
The idea of coherent CW, admittedly using a TV signal derived reference
rather than a GPS derived one, has been published before.

The benefits of a co-referenced SSB system are less easy to evaluate.
Post by Iain Young, G7III
Post by Gareth's Downstairs Computer
Agreed, this moves away from the simplistic approaches
that are the essence of _REAL_ amateur / ham radio by
making use of the constellation of the GPS satellites
whose system complexity is way beyond anything that
we might construct.
I think G3RUH, and G4JNT (amongst others) would disagree with
you. They have both done "Ground Segments" for the GPS System.
You forgot, the village idiot's expertise is way below those of us who have
actually produced professional kit.

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