Re: LO Phase Noise and wideband front ends

F6DZK Michel

Hello,

I remember having studied oscillators in a lab for quite some time many years ago.

Phase noise contributors (in bipolar transistors oscillators) were indeed kTB noise of resistors (including base resistor and resonator losses) and by shot noise of junctions : 2*q*Ie
In the oscillotor structure I then studied, shot noise was the dominant contributor.
AM noise is eliminated by the very non linear behaviour of the oscillator.
We found out then that the more non-linear, the better (to some point though as loaded Q should not be too low, about half of unloaded Q if I remember well) !

I have no idea how this translates to CMOS or GaAs Fets.

73 Michel F6DZK

2016-06-14 22:33 GMT+02:00 Christopher Bartram cbartram@... [ukmicrowaves] :

Hello John
> Are you sure that amplifier noise is AM noise? I always thought that
> amplified thermal noise, which this is, was an equal mix of both AM
> and PM noise.

I suspect that this is a situation where on one level we're both right!
Of course, thermal noise will have both varying phase and amplitude
components, and at a quantum level, I believe thermal noise has a
low-pass characteristic. (Physicists please comment - I'm just a
horny-handed engineer... ) But when I say thermal noise or AM noise, I
refer to noise defined by kTB, which has no practical frequency
dependence. Phase noise, though, is generated by the action of an
oscillator, and can be thought of effectively as angle modulation of
that oscillator by a noise source.

It's possible to measure the amplitude and phase noise generated by an
oscillator independently - amplitude noise is surprisingly easy to
measure. Phase noise, though, is primarily dependent on the oscillator's
amplitude (kTB) noise and the Q of its resonator, and it's measurement
requires a bit of subtlety. I could give you a reference to Leeson's
classic paper on oscillator analysis and phase noise if you are interested.

The term 'phase noise' tends to bandied about without much thought -
that's true of both amateurs and many professionals - and the real
meaning of the term has become muddied in many people's heads.

73

Chris
GW4DGU

--

Re: LO Phase Noise and wideband front ends

Ole OZ2OE

Hi Chris - I remember once being taught about the low pass characteristic of kTB noise - as it must have because a flat characteristic would imply indefinite power at indefinite bandwith.
A simple approximation has the cut-off at f=kT/h - somewhere in the Terahertz range. Google "Johnson-Nyquist noise"
73 Ole, OZ2OE

Den 14. juni 2016 kl. 22.33.34 +02.00, skrev Christopher Bartram cbartram@... [ukmicrowaves] :

Hello John
> Are you sure that amplifier noise is AM noise? I always thought that
> amplified thermal noise, which this is, was an equal mix of both AM
> and PM noise.

I suspect that this is a situation where on one level we're both right!
Of course, thermal noise will have both varying phase and amplitude
components, and at a quantum level, I believe thermal noise has a
low-pass characteristic. (Physicists please comment - I'm just a
horny-handed engineer... ) But when I say thermal noise or AM noise, I
refer to noise defined by kTB, which has no practical frequency
dependence. Phase noise, though, is generated by the action of an
oscillator, and can be thought of effectively as angle modulation of
that oscillator by a noise source.

It's possible to measure the amplitude and phase noise generated by an
oscillator independently - amplitude noise is surprisingly easy to
measure. Phase noise, though, is primarily dependent on the oscillator's
amplitude (kTB) noise and the Q of its resonator, and it's measurement
requires a bit of subtlety. I could give you a reference to Leeson's
classic paper on oscillator analysis and phase noise if you are interested.

The term 'phase noise' tends to bandied about without much thought -
that's true of both amateurs and many professionals - and the real
meaning of the term has become muddied in many people's heads.

73

Chris
GW4DGU

--

Re: Stand alone JT4G

John McCarthy

Thanks Chris for mentioning KST2me just downloaded and installed, yep looks like I'm going to go down that line as well as really don't like taking the home laptop out /p to many things to go wrong and don't know how I'd get a replacement pass the XYL !

John

Re: Stand alone JT4G

John McCarthy

Yes google virtual cable software I seem to remember VB cable as the one I last used

73 John

On Tuesday, 14 June 2016, 21:27, "Edward Harland g3vpf@... [ukmicrowaves]" wrote:

Can I ask a slightly tangential question. I use a Intel NUC computer with a funcube dongle and SDR# to monitor the local 3cms beacons. I also have the WSJT package running on the same PC. Is there any way of feeding the SDR# output directly into the WSJT package? At present I have two audio interfaces with the output of one feeding the input of the other via a connecting cable.

Ed G3VPF

On Tuesday, 14 June 2016, 20:05, "Christopher Bartram cbartram@... [ukmicrowaves]" wrote:

Andy wrote:
> What about a small - older second hand perhaps - notebook.
Which is exactly what I did. As I have a long history of using
IBM/Lenovo ThinkPad laptops, I went for a Lenovo/IBM X60. In its day
this was a powerful compact dual-core machine with a 12inch display.
It's still capable of running anything you'd need out portable, and it
is built like the proverbial masonry tŷ bach! With a newish oversized
battery it lasts for several hours running a 3G dongle and KST2ME.

X60s are currently going for about £40 on Epay.

73

Chris
GW4DGU
--

Re: Stand alone JT4G

Andy G4JNT

That's the way I do it - multiple USB soundcard dongles.    You know where you are with real interface cables; it  keeps life simple

If you have a full duplex soundcard, the  Rx and Tx portions can run independently so you just wrap round from output to input  - turning off local monitor if it is an option

Many people use  Virtual Audio Cable, or VAC.   Software that gives you effective connection of sound cards. Suggest you Google it

Andy  G4JNT

On 14 June 2016 at 21:27, Edward Harland g3vpf@... [ukmicrowaves] wrote:

Can I ask a slightly tangential question. I use a Intel NUC computer with a funcube dongle and SDR# to monitor the local 3cms beacons. I also have the WSJT package running on the same PC. Is there any way of feeding the SDR# output directly into the WSJT package? At present I have two audio interfaces with the output of one feeding the input of the other via a connecting cable.

Ed G3VPF

On Tuesday, 14 June 2016, 20:05, "Christopher Bartram cbartram@... [ukmicrowaves]" <ukmicrowaves@...> wrote:

Andy wrote:
> What about a small - older second hand perhaps - notebook.
Which is exactly what I did. As I have a long history of using
IBM/Lenovo ThinkPad laptops, I went for a Lenovo/IBM X60. In its day
this was a powerful compact dual-core machine with a 12inch display.
It's still capable of running anything you'd need out portable, and it
is built like the proverbial masonry tŷ bach! With a newish oversized
battery it lasts for several hours running a 3G dongle and KST2ME.

X60s are currently going for about £40 on Epay.

73

Chris
GW4DGU
--

Re: LO Phase Noise and wideband front ends

Christopher Bartram <cbartram@...>

Hello John
Are you sure that amplifier noise is AM noise? I always thought that amplified thermal noise, which this is, was an equal mix of both AM and PM noise.
I suspect that this is a situation where on one level we're both right! Of course, thermal noise will have both varying phase and amplitude components, and at a quantum level, I believe thermal noise has a low-pass characteristic. (Physicists please comment - I'm just a horny-handed engineer... ) But when I say thermal noise or AM noise, I refer to noise defined by kTB, which has no practical frequency dependence. Phase noise, though, is generated by the action of an oscillator, and can be thought of effectively as angle modulation of that oscillator by a noise source.

It's possible to measure the amplitude and phase noise generated by an oscillator independently - amplitude noise is surprisingly easy to measure. Phase noise, though, is primarily dependent on the oscillator's amplitude (kTB) noise and the Q of its resonator, and it's measurement requires a bit of subtlety. I could give you a reference to Leeson's classic paper on oscillator analysis and phase noise if you are interested.

The term 'phase noise' tends to bandied about without much thought - that's true of both amateurs and many professionals - and the real meaning of the term has become muddied in many people's heads.

73

Chris
GW4DGU

--

Re: Stand alone JT4G

Ed G3VPF

Can I ask a slightly tangential question. I use a Intel NUC computer with a funcube dongle and SDR# to monitor the local 3cms beacons. I also have the WSJT package running on the same PC. Is there any way of feeding the SDR# output directly into the WSJT package? At present I have two audio interfaces with the output of one feeding the input of the other via a connecting cable.

Ed G3VPF

On Tuesday, 14 June 2016, 20:05, "Christopher Bartram cbartram@... [ukmicrowaves]" wrote:

Andy wrote:
> What about a small - older second hand perhaps - notebook.
Which is exactly what I did. As I have a long history of using
IBM/Lenovo ThinkPad laptops, I went for a Lenovo/IBM X60. In its day
this was a powerful compact dual-core machine with a 12inch display.
It's still capable of running anything you'd need out portable, and it
is built like the proverbial masonry tŷ bach! With a newish oversized
battery it lasts for several hours running a 3G dongle and KST2ME.

X60s are currently going for about £40 on Epay.

73

Chris
GW4DGU
--

24GHz Sunday

Christopher Bartram <cbartram@...>

Site access and weather permitting - the latest Met.Office forecast is suggesting RH in 55% region here - I expect to be QRV on 24GHz.

Call: GW4DGU/P
Locator:IO82en80
Band: 24GHz only
Antenna: 0.8m offset dish
Transverter: 2W, 2dB NF. not yet GPS locked (sorry ...)
Talkback: ON4KST or 07545 094490
Operating Times: probably about 10 - 14bst, unless I have pile-ups
Looking for any QSOs including JO02, John!

--

73

Chris
GW4DGU

Re: Heliax FSJ1-50A connectors

Roger Ray

Mike,

I think I have 2 spare, just need to check the part numbers that they are for FSJ1-50A. If correct I will send to you, if you email me direct.

Roger

Re: LO Phase Noise and wideband front ends

John G3UUT <yahoo@...>

Chris,
Are you sure that amplifier noise is AM noise? I always thought that amplified thermal noise, which this is, was an equal mix of both AM and PM noise.
73 John G3UUT

On 14/06/2016 08:54, Christopher Bartram cbartram@... [ukmicrowaves] wrote:

I haven't seen the original post on this , but, I suspect that the
problem isn't Phase Noise. For far too many people phase noise is a
pretty diffuse concept, and it gets blamed for a lot of effects for
which it's not responsible!

Phase noise is, in effect, a form of wideband frequency modulation, and
falls away quite quickly at 20dB/octave as you move away from the
carrier. What I believe, from reading Andy's post is that the problem is
amplitude domain noise (AM noise) caused by eg. amplifiers in the signal
path. This can have a pretty flat frequency/amplitude characteristic.

'Phase noise' gets the blame for many effects which are caused by AM
noise, and is a particular nuisance in wideband systems, but it behaves
differently to AM noise. Phase noise won't be cancelled in a balanced
mixer, but AM noise will be.

73

Chris
GW4DGU

 Virus-free. www.avast.com

Re: Stand alone JT4G

Christopher Bartram <cbartram@...>

Andy wrote:
What about a small - older second hand perhaps - notebook.
Which is exactly what I did. As I have a long history of using IBM/Lenovo ThinkPad laptops, I went for a Lenovo/IBM X60. In its day this was a powerful compact dual-core machine with a 12inch display. It's still capable of running anything you'd need out portable, and it is built like the proverbial masonry tŷ bach! With a newish oversized battery it lasts for several hours running a 3G dongle and KST2ME.

X60s are currently going for about £40 on Epay.

73

Chris
GW4DGU
--

Re: Stand alone JT4G

Andy G4JNT

I did upgrade my memory to 2G though - as with more than two progs running, it took an excrutiatingly long time swapping.   Saw a Youtube video how to do it

A

On 14 June 2016 at 19:46, g7jtt@... [ukmicrowaves] wrote:

great looks like the Pi might not be the way to go then as those netbooks are around £20 with screen and sound in/out.

John

Re: Stand alone JT4G

John McCarthy

great looks like the Pi might not be the way to go then as those netbooks are around £20 with screen and sound in/out.

John

Re: Stand alone JT4G

Andy G4JNT

I haveWin 7 Starter on my HP notebook.   Its a horrible OS for general purpose use, too deliberately cut back.
But it runs WSJT-10   and  -X OK.

Also have an old Dell latitude notebook ,  Few hundred MHz ish processor  witha mere 500Meg memory !  That runs WSJT-X (slowly) ,  and WSJT10 perfectly well.

A

On 14 June 2016 at 19:29, g7jtt@... [ukmicrowaves] wrote:

one of the netbooks with a Intel Atom chip they often run windows 7 starter many used to surf Facebook from the sofa. But I guess you've answered it in that its later than xp so should run the older version but don't suppose it will cope with to much more?

John

On Tuesday, 14 June 2016, 19:20, "Andy Talbot andy.g4jnt@... [ukmicrowaves]" <ukmicrowaves@...> wrote:

Not what you mean by "cut down"
If they run an OS any later than Win 98, they'll run WSJT - at least the original version

The new WSJT-X under development loads more processing into teh software to allow multiple decoding for some modes.  And that chews up processor power.
But single JT4 decodes hardly taxes things

'jnt

On 14 June 2016 at 19:16, g7jtt@... [ukmicrowaves] wrote:

You make a good point Andy just looked on Ebay and I'm surprised how cheap they are, what about the cut down laptops/netbooks would one of those run JT ? as they are small enough and consume less power that their larger cousins.

John

Re: Stand alone JT4G

John McCarthy

one of the netbooks with a Intel Atom chip they often run windows 7 starter many used to surf Facebook from the sofa. But I guess you've answered it in that its later than xp so should run the older version but don't suppose it will cope with to much more?

John

On Tuesday, 14 June 2016, 19:20, "Andy Talbot andy.g4jnt@... [ukmicrowaves]" wrote:

Not what you mean by "cut down"
If they run an OS any later than Win 98, they'll run WSJT - at least the original version

The new WSJT-X under development loads more processing into teh software to allow multiple decoding for some modes.  And that chews up processor power.
But single JT4 decodes hardly taxes things

'jnt

On 14 June 2016 at 19:16, g7jtt@... [ukmicrowaves] wrote:

You make a good point Andy just looked on Ebay and I'm surprised how cheap they are, what about the cut down laptops/netbooks would one of those run JT ? as they are small enough and consume less power that their larger cousins.

John

Re: Stand alone JT4G

Andy G4JNT

Not what you mean by "cut down"
If they run an OS any later than Win 98, they'll run WSJT - at least the original version

The new WSJT-X under development loads more processing into teh software to allow multiple decoding for some modes.  And that chews up processor power.
But single JT4 decodes hardly taxes things

'jnt

On 14 June 2016 at 19:16, g7jtt@... [ukmicrowaves] wrote:

You make a good point Andy just looked on Ebay and I'm surprised how cheap they are, what about the cut down laptops/netbooks would one of those run JT ? as they are small enough and consume less power that their larger cousins.

John

Re: Stand alone JT4G

John McCarthy

You make a good point Andy just looked on Ebay and I'm surprised how cheap they are, what about the cut down laptops/netbooks would one of those run JT ? as they are small enough and consume less power that their larger cousins.

John

Re: Stand alone JT4G

Andy G4JNT

What about a small - older second hand perhaps - notebook. Like the HP Ones.   A few tens of quid from boot sales / junk sales and more than adequate for WSJT. Which by the tiome youv'e added few perpherals can come out cheaper than a RPi.    Mine runs from 15V and takes 1.5A, so a simple switcher from a 12V battery keeps it going from a portable / mobile venue.

Mine only has microphone input and phone output on a single 4-way jack.  But nothing two resistors and a custom lead can't cope with.   If you need I/O. there's always the FTDI USB COm port family

Andy  G4JNT

On 14 June 2016 at 09:58, 'g7jtt@...' g7jtt@... [ukmicrowaves] wrote:

Hi John this is why I like the idea of something like the Pi it saves lugging out an expensive laptop plus by all accounts the Pi can be used with the SDR to. If it is possible to use a Pi with a small touch screen with JT4/SDR installed there are enough USB sound cards that work with the Pi plus with all the GDO pins available one could be used for put as well ? Maybe this could become a uwave club project ?

All best John

I would start with JT4G as it has proved itself over last few years to be resilient to extremes of RS /frequency instability ,manual tracking etc .
I purchased a laptop to handle JT operations out /P but the additional effort needed does place demands on the primary station operation .
A simple dedicated audio interfaced box for JT in/out would good , leaving the SDR to monopolise the laptop.
John
G0API

Re: Stand alone JT4G

John McCarthy

Oops "ptt" not "put" 😖

On Tue, 14 Jun, 2016 at 9:58, 'g7jtt@...' g7jtt@... [ukmicrowaves]
wrote:

Hi John this is why I like the idea of something like the Pi it saves lugging out an expensive laptop plus by all accounts the Pi can be used with the SDR to. If it is possible to use a Pi with a small touch screen with JT4/SDR installed there are enough USB sound cards that work with the Pi plus with all the GDO pins available one could be used for put as well ? Maybe this could become a uwave club project ?

All best John

I would start with JT4G as it has proved itself over last few years to be resilient to extremes of RS /frequency instability ,manual tracking etc .
I purchased a laptop to handle JT operations out /P but the additional effort needed does place demands on the primary station operation .
A simple dedicated audio interfaced box for JT in/out would good , leaving the SDR to monopolise the laptop.
John
G0API

Re: Stand alone JT4G

John McCarthy

Hi John this is why I like the idea of something like the Pi it saves lugging out an expensive laptop plus by all accounts the Pi can be used with the SDR to. If it is possible to use a Pi with a small touch screen with JT4/SDR installed there are enough USB sound cards that work with the Pi plus with all the GDO pins available one could be used for put as well ? Maybe this could become a uwave club project ?
All best John

On Tue, 14 Jun, 2016 at 9:44, John Fell john.g0api@... [ukmicrowaves]
wrote:

I would start with JT4G as it has proved itself over last few years to be resilient to extremes of RS /frequency instability ,manual tracking etc .
I purchased a laptop to handle JT operations out /P but the additional effort needed does place demands on the primary station operation .
A simple dedicated audio interfaced box for JT in/out would good , leaving the SDR to monopolise the laptop.
John
G0API