Date   

Re: Measuring Noise Figure

Martin - G8JNJ
 

Hi Chris,

Your method sounds interesting - I'd like to try it.

Can you outline the calculations required, or point to a site or source that has the detail ?

Regards,

Martin - G8JNJ

www.g8jnj.net
www.tc2m.info
http://websdr.suws.org.uk


Re: F/GM0USI/P IN78/88 3cm next week

Ed G3VPF
 

Alan

Regrettably Weds is the only day this week I can't make, tied up in a meeting in Southampton all day. For info there was all the visual signs of a super-refraction duct out in the Channel this afternoon. Also, the weather will change overnight Tuesday into Wednesday to much cooler air so little chance of surface ducts after that.

Ed G3VPF


On Mon, 18 Jul, 2016 at 16:33, 'g7jtt@...' g7jtt@... [ukmicrowaves]
wrote:
 

Yep you've picked a week of good weather Wednesday is good for me, have to be somewhere in the morning but should be done by lunch so will head straight over to lane end 

73 John


 

Hi there,

Have arrived in the Roscoff area and am staying for a week in St Pol de.Leon just to the south...wx looks extremely warm tomorrow so thinking Wednesday around 13-1500local...local time here is 1 hour ahead...
I can use my phone for calls and data so l can easily phone or attempt to get on KST...l will be using 10368.120...cw possible also
Kit is only around 1.75w to a flatflat panel antenna of around 20db...
Hopefully l haven't forgotten anything..
If Wednesday doesn't suit l may be able to make time on another occasion. .
Locator should be about IN88AQ but that may change if l can't get a parking space hi.
73 Alan F/GM0USI/P 07785744643




Sent from my Samsung device
-------- Original message --------
From: "Alan Dimmick dimmickalan@... [ukmicrowaves]"
Date: 18/07/2016 01:03 (GMT+01:00)
To: ukmicrowaves@...
Subject: Re: [ukmicrowaves] Re: F/GM0USI/P IN78/88 3cm next week

 

No probs Adrian,

Am.on the ferry as l write...l think tues or wed is looking possible but will post further details. .

73 Alan



Sent from my Samsung device


-------- Original message --------
From: "Adrian whatmore g4uvz@... [ukmicrowaves]"
Date: 17/07/2016 14:41 (GMT+00:00)
To: ukmicrowaves@...
Subject: [ukmicrowaves] Re: F/GM0USI/P IN78/88 3cm next week

 

I too am keen to work across from the south west from one of my sites near Taunton ..I think that you plan to work Edward VPF ..so could deploy at a similar time ..Happy for a timed sked if neccessary,,I too run the DGU but now with a 7 watt PA ,so we should have no problems
Adrian 07778 523 832   adrianwhatmore248@...


Re: Measuring Noise Figure

richard@...
 

"Thoroughly disagree"  Thanks for your reply Chris. I am not clear with which approach you thoroughly disagree with however.

a) the gain method of measuring noise figure
b) measuring without an input load
c) measuring with an input load; or possibly
d) Derek's approach.

73 Richard G3CWI


Re: Measuring Noise Figure

Chris Trask <christrask@...>
 

Thoroughly disagree. I use the 3dB method, which requires a 50-ohm termination, a 3-dB attenuation pad, a noise source, and a means for measuring output noise power (typically a spectrum analyzer). You first measure the amplifier output noise with the 50-ohm termination at the input. Then you add the 3-dB attenuator to the output and the noise source to the input. You adjust the noise source power until the two measurements are the same, then go through some calculations to determine the NF.


I watched a Youtube video recently about measuring noise figure using the measured gain of an amplifier
and a spectrum analyser. The thing that I found odd was that the video maker did not terminate the input
of the amplifier - he said it did not matter. I can think of two reasons why it might matter:

1) the input load resistor provides the base thermal noise level (I suppose it might not matter much if
the amplifier is very noisy)
2) some amplifiers are not entirely stable when un-terminated.

Would you agree?


Chris

When the going gets weird, the weird turn pro
- Hunter S. Thompson


432 and Above EME Newsletter for July 2016

rein0zn@...
 

Hello All,

The 432 MHz and Above EME Newsletter for July 2016 by K2UYH can be downloaded from:

http://www.nitehawk.com/rasmit/em70cm.html

-- Enjoy

73 Rein W6SZ


Re: Measuring Noise Figure

Derek Kozel <derek.kozel@...>
 

There are different approaches to measuring noise figure. I always use a y factor test and leave the noise source attached to the input of the amplifier/receiver. Powering on and off the noise source provides the change in stimulus to calculate the noise figure but keeps the termination as close as possible, including reducing thermal changes in the short term.

On Mon, Jul 18, 2016 at 7:09 AM, richard@... [ukmicrowaves] <ukmicrowaves@...> wrote:
 

Hi all


I watched a Youtube video recently about measuring noise figure using the measured gain of an amplifier and a spectrum analyser. The thing that I found odd was that the video maker did not terminate the input of the amplifier - he said it did not matter. I can think of two reasons why it might matter:


1) the input load resistor provides the base thermal noise level (I suppose it might not matter much if the amplifier is very noisy)

2) some amplifiers are not entirely stable when un-terminated.


Would you agree?


73 Richard G3CWI



Re: F/GM0USI/P IN78/88 3cm next week

John McCarthy
 

Yep you've picked a week of good weather Wednesday is good for me, have to be somewhere in the morning but should be done by lunch so will head straight over to lane end 
73 John


On Mon, 18 Jul, 2016 at 16:28, Alan Dimmick dimmickalan@... [ukmicrowaves]
wrote:
 

Hi there,

Have arrived in the Roscoff area and am staying for a week in St Pol de.Leon just to the south...wx looks extremely warm tomorrow so thinking Wednesday around 13-1500local...local time here is 1 hour ahead...
I can use my phone for calls and data so l can easily phone or attempt to get on KST...l will be using 10368.120...cw possible also
Kit is only around 1.75w to a flatflat panel antenna of around 20db...
Hopefully l haven't forgotten anything..
If Wednesday doesn't suit l may be able to make time on another occasion. .
Locator should be about IN88AQ but that may change if l can't get a parking space hi.
73 Alan F/GM0USI/P 07785744643




Sent from my Samsung device
-------- Original message --------
From: "Alan Dimmick dimmickalan@... [ukmicrowaves]" <ukmicrowaves@...>
Date: 18/07/2016 01:03 (GMT+01:00)
To: ukmicrowaves@...
Subject: Re: [ukmicrowaves] Re: F/GM0USI/P IN78/88 3cm next week

 

No probs Adrian,

Am.on the ferry as l write...l think tues or wed is looking possible but will post further details. .

73 Alan



Sent from my Samsung device


-------- Original message --------
From: "Adrian whatmore g4uvz@... [ukmicrowaves]"
Date: 17/07/2016 14:41 (GMT+00:00)
To: ukmicrowaves@...
Subject: [ukmicrowaves] Re: F/GM0USI/P IN78/88 3cm next week

 

I too am keen to work across from the south west from one of my sites near Taunton ..I think that you plan to work Edward VPF ..so could deploy at a similar time ..Happy for a timed sked if neccessary,,I too run the DGU but now with a 7 watt PA ,so we should have no problems
Adrian 07778 523 832   adrianwhatmore248@...


Re: F/GM0USI/P IN78/88 3cm next week

Alan
 

Hi there,

Have arrived in the Roscoff area and am staying for a week in St Pol de.Leon just to the south...wx looks extremely warm tomorrow so thinking Wednesday around 13-1500local...local time here is 1 hour ahead...
I can use my phone for calls and data so l can easily phone or attempt to get on KST...l will be using 10368.120...cw possible also
Kit is only around 1.75w to a flatflat panel antenna of around 20db...
Hopefully l haven't forgotten anything..
If Wednesday doesn't suit l may be able to make time on another occasion. .
Locator should be about IN88AQ but that may change if l can't get a parking space hi.
73 Alan F/GM0USI/P 07785744643




Sent from my Samsung device

-------- Original message --------
From: "Alan Dimmick dimmickalan@... [ukmicrowaves]"
Date: 18/07/2016 01:03 (GMT+01:00)
To: ukmicrowaves@...
Subject: Re: [ukmicrowaves] Re: F/GM0USI/P IN78/88 3cm next week

 

No probs Adrian,

Am.on the ferry as l write...l think tues or wed is looking possible but will post further details. .

73 Alan



Sent from my Samsung device


-------- Original message --------
From: "Adrian whatmore g4uvz@... [ukmicrowaves]"
Date: 17/07/2016 14:41 (GMT+00:00)
To: ukmicrowaves@...
Subject: [ukmicrowaves] Re: F/GM0USI/P IN78/88 3cm next week

 

I too am keen to work across from the south west from one of my sites near Taunton ..I think that you plan to work Edward VPF ..so could deploy at a similar time ..Happy for a timed sked if neccessary,,I too run the DGU but now with a 7 watt PA ,so we should have no problems
Adrian 07778 523 832   adrianwhatmore248@...


Re: Further Millimetric report Sunday 17th July

Roger Ray
 

John - That is a great achievement considering the high humidity.
That means there was some form of communication on Sunday, on all bands 24GHz and above.
Thats a first!!

Roger
G8CUB


Measuring Noise Figure

richard@...
 

Hi all


I watched a Youtube video recently about measuring noise figure using the measured gain of an amplifier and a spectrum analyser. The thing that I found odd was that the video maker did not terminate the input of the amplifier - he said it did not matter. I can think of two reasons why it might matter:


1) the input load resistor provides the base thermal noise level (I suppose it might not matter much if the amplifier is very noisy)

2) some amplifiers are not entirely stable when un-terminated.


Would you agree?


73 Richard G3CWI


Re: First UK QSO on the 122 GHz band

mjniman@...
 


Congrats on another mmWave first!

Whilst we have often not favoured the 122GHz band due to the Oxgyen resonance losses (similar to the 60 GHz band)  - all activity counts! - and like the exempt 60Ghz band is expected to see a growth in new chips and short range devices

73

 Murray G6JYB

PS Video/pics welcome of course!


Further Millimetric report Sunday 17th July

usuallyqrt@...
 

To add a bit more to Sundays Millimetric activity reports. G8KQW was able to receive my 241020 MHz auto keyer signal at 5 by 3 by  3.9Km distance LOS across Winchester.  This was one way reception. So signals a bit stronger at this shorter distance than my previous test distance of  6.75km a month ago which was marginal for signal level.

73 John G8ACE  


10GHz JT4G test Tuesday Evening

Andy G4JNT
 

Tomorrow (Tuesday 19th)   I'll be lending moral support to someone taking part in the 1.3GHz AC event.   Operating from Crabwood Farm near Winchester IO91HB65

I'll take along my 10GHz PortaBeacon and leave it running for the duration.

Crabwood Farm is one of the few sites local to me with any take off to te north, so will be pointing the 20 degree beamwidth horn that way.   In fact, trees screen the site for other directions, so NW to NE is about its only good direction for proper uWaves.

Mode JT4G only, odd and even minute transmissions carry different messages. Frequency 10368.350MHz  (Tone 0),   use SSB tuning ref 10368.3492MHz. Frequency is determined by OCXO alone, so expect a few tens of Hz uncertainty  Power around 8dBW EIRP, ie about the same as GB3SCX

If anyone wants the horn tweaked, my mobile no is 07576 765856,  and I may even have KST on hand as 3G coverage is excellent up there, being right under one of their masts.

Andy  G4JNT


Re: First UK QSO on the 122 GHz band

Barry Chambers
 

Hi Chris, Roger

Another fantastic achievement! Well done.

73

Barry, G8AGN
On 18/07/2016 08:29, Chris G0FDZ chris@... [ukmicrowaves] wrote:

 

The first UK QSO on the 122 GHz band took place yesterday the 17th of July at 13:45 hours UTC between Roger G8CUB/P and Chris G0FDZ/P with both stations located at Hackpen, Wiltshire  (IO91CL). The distance was 120m and the CW reports were 599 both ways. An earlier attempt at 5km failed for a two way QSO. As well as signals on 134 GHz, of which only a very weak one way QSO was possible on that band, only the merest hint of a signal on 122 GHz was heard. The 122 GHz band is noted for its high signal attenuation due additionally to atmospheric oxygen as well as water vapour attenuation. The weather during the contest gave high humidity, and absorption of all millimetre wave frequencies was considered by many to be high. Although signals over the short distance were very good an attempt will be made soon over 1.5kms. Power levels were 70uW for Chris G0FDZ & 300uW for Roger G8CUB. One feature of G0FDZ’s system was the use of a slab type mixer which has been recently developed to make millimetre wave mixers easier to construct.

With a QSO being achieved on this band it means that every allocated UK band has now has had at least one QSO.

A full report on the QSO and progress will appear in the UK Microwave Groups Scatterpoint newsletter, and photos and video will be available soon.

Regards

Chris G0FDZ


OZ5N Auto PLL

geoffrey pike
 

Back to DC matters at 10.368 GHz, i finally fitted my OZ5N auto pll and this is what happened.
Well it really didn't want to lock up at all, i changed the 82 p at the crystal to 56p. I gave everything some time to warm up and although
the blue LED flashed at 1 sec intervals it just wasn't for locking up.I adjusted the coil for a resting frequency about 200 Hz high and tried again and it locked up OK. I measured the control voltage at 1.04v and readjusted for 1.7v as i thought that this would be better and sure enough when i tried it all again the lock up was within 2 seconds.
So from a cold DB6NT it takes about 2 secs to lock but when the 10 MHz ref is removed and the xtal is up to temp it takes about 10 secs to lock.
I then put it all back together again and got my signal source fro 10.368200 GHz going and tuned in spot on 144.200 on the 290 and it just sits there rock steady T9. So that only leaves azimuth control of the dish as an unknown !.
regards
Geoff
GI0GDP
I measured the crystal frequency on the collector of the first tripler via a 22p cap


Re: First UK QSO on the 122 GHz band

g4bao
 

Nice one Chris and Roger, just in time for September "GHz bands"

If anyone else has news of note, I'm starting to write the column this week.

73
John

On 18 July 2016 at 08:40, Christopher Bartram cbartram@... [ukmicrowaves] <ukmicrowaves@...> wrote:
 

Well done guys!

Yes, yesterday was plagued by gas losses. With RH at very close to 100%
here, even a test from home to Clee Hill on 24GHz failed ...

Keep up the good work!

73

Chris
GW4DGU

--
Christopher Bartram MIET
Christopher Bartram RF Design
Llygad yr Haul
Carno
CAERSWS
Powys SY17 5LE

phone: +44 1686 237732
mobile: +44 7545 094490
email: cbartram@...
URL: www.christopherbartramrfdesign.com

Note: This message is for the named person's use only. It may contain confidential, proprietary or legally privileged information. No confidentiality or privilege is waived or lost by any mistransmission. If you receive this message in error, please immediately delete it and all copies of it from your system, destroy any hard copies of it and notify the sender. You must not, directly or indirectly, use, disclose, distribute, print, or copy any part of this message if you are not the intended recipient. Christopher Bartram RF Design reserves the right to monitor all e-mail communications through its network. Any views expressed in this message are those of the individual sender, except where the message states otherwise and the sender is authorised to state them to be the views of any such entity.



Re: 134 GHz frequency allocation

Roger Ray
 

Hi Bill,

The way most of us get to 134GHz. Is Elcom synthesiser on 11.2GHz, a Broadern module (X3 and Amp) giving 33.6GHz into the mixer. With the same for LO, 11.23666 x3 to 33.71 (134.84), giving 440MHz IF.
Although fine for TX the Broadern is a bit noisy as LO, so for >10km range I use a separate X3/amp in the RX LO chain.

Broadern modules are still on ebay, although the supply of 11.2-12GHz Elcom synthesisers seams to have dried up.

Roger
G8CUB


Re: Question - DBES105A Flip Chip Diodes ?

Roger Ray
 

Alan.

I did a 'last time' buy of these diodes last year of 100. However these have all now been distributed, leaving me with less than intended. So unless anyone has bought some, and are not going to use them, you will find it difficult now to find any now unfortunately.

A great pity they stopped production!

Roger
G8CUB


Re: First UK QSO on the 122 GHz band

Christopher Bartram <cbartram@...>
 

Well done guys!

Yes, yesterday was plagued by gas losses. With RH at very close to 100% here, even a test from home to Clee Hill on 24GHz failed ...

Keep up the good work!

73

Chris
GW4DGU

--
Christopher Bartram MIET
Christopher Bartram RF Design
Llygad yr Haul
Carno
CAERSWS
Powys SY17 5LE

phone: +44 1686 237732
mobile: +44 7545 094490
email: cbartram@theiet.org
URL: www.christopherbartramrfdesign.com

Note: This message is for the named person's use only. It may contain confidential, proprietary or legally privileged information. No confidentiality or privilege is waived or lost by any mistransmission. If you receive this message in error, please immediately delete it and all copies of it from your system, destroy any hard copies of it and notify the sender. You must not, directly or indirectly, use, disclose, distribute, print, or copy any part of this message if you are not the intended recipient. Christopher Bartram RF Design reserves the right to monitor all e-mail communications through its network. Any views expressed in this message are those of the individual sender, except where the message states otherwise and the sender is authorised to state them to be the views of any such entity.


First UK QSO on the 122 GHz band

Chris G0FDZ
 

The first UK QSO on the 122 GHz band took place yesterday the 17th of July at 13:45 hours UTC between Roger G8CUB/P and Chris G0FDZ/P with both stations located at Hackpen, Wiltshire  (IO91CL). The distance was 120m and the CW reports were 599 both ways. An earlier attempt at 5km failed for a two way QSO. As well as signals on 134 GHz, of which only a very weak one way QSO was possible on that band, only the merest hint of a signal on 122 GHz was heard. The 122 GHz band is noted for its high signal attenuation due additionally to atmospheric oxygen as well as water vapour attenuation. The weather during the contest gave high humidity, and absorption of all millimetre wave frequencies was considered by many to be high. Although signals over the short distance were very good an attempt will be made soon over 1.5kms. Power levels were 70uW for Chris G0FDZ & 300uW for Roger G8CUB. One feature of G0FDZ’s system was the use of a slab type mixer which has been recently developed to make millimetre wave mixers easier to construct.

With a QSO being achieved on this band it means that every allocated UK band has now has had at least one QSO.

A full report on the QSO and progress will appear in the UK Microwave Groups Scatterpoint newsletter, and photos and video will be available soon.

Regards

Chris G0FDZ