Date   

Re: OT: HF+ Discovery as part of a "simple" NF meter

jdow
 

On 20200817 18:23:13, Marcus Ramos wrote:
Well ...

I still trying to remember why I assemble this source this way. If we take a look at NoiseComm paper, they show the diode from ground to a resitor of *certain* value ... I guess it's used to limit diode current to 8 ... 12mA.

I read some (long) time ago that standard NF meter switches ENR sources with -21V on/off. The attenuator at ENR output have the function to act as a 50 ohm resistor at the room temp.

I remember that I did some simulation with diode S parameters trying to create a constant Z source. The ceramic cap is a last week adition, when testing this source conected to HF+ Discovery I noticed that noise amplitude decreases below 10MHz or so. But adding this cap "solve" this problem, noise was almost flat until 100KHz or so.

At the time of building this ENR source I was more interested in LNAs for EME on 144, 432, 1296 and 2304. Why not 10G? May be another diode fits actual needs. But 30 to 35dB ENR is a lot of noise.

Could the temp changes on resistor (the attenuator) and diode be the same? They share the same substrat. Ok, diode will sink 12v/10mA=120mW half of the cycle. Need do test.

Definitely it could unless you took measures to cool the substrate or better yet, measure it while you were pulsing the noise on and off. Then you can use the real "kTB" number rather than the nominal room temperature values. As I noted one amplifier I build early on in my career brought this home to me. Best I could "guess" is about 1/4 dB at 11.5 MHz. I had to leave power off the empty state electronics (vacuum tube) diode noise generator to prevent it heating up to much. Then take the reading very rapidly. (It was an HP 342A. I see some on E-Bay. They're useless without the head that had the diode inside. I believe the diode was a 6AL5.)

And - yes - the decoupling harness was a try to create a good decoupling response from 100MHz to 10GHz, takin into accout ESR of those caps and was the result of some simulation at Genesys or other tool ... +15 years ago.

May be better finish the QEX project =:)

73
MR

It is always good to finish one's projects. It really REALLY takes a lot of self discipline for me. I go far enough to prove I can do it and too easily lose interest at that point.

{^_^}

Em 17/08/2020 09:02, jdow escreveu:
You might get more accurate results injecting a modest signal along with the noise. This was brought home to me when I found myself working in the lab on network control software for the AN/USC-28 DSCS SatCom modem. Apparently the way it was designed you needed an interfering signal to get it to work in the lab. The front end was left off for the test because back to back, even with good attenuators, was too strong. It required some interfering signal for it to work correctly with the normally expected inputs to the receiver post front end gain. Adding a little signal made it work like magic. You get more bits by averaging signals, decimation is one way of doing this. Those extra bits were critical to making it work. They may also prove critical for your measurement effort.

Another thing to consider is the diode heating up. If your noise figure is low a hot 50 ohm resistor will foo your noise figure reading, making it look lower than it is.

With an ancient HP 6AL5 based noise figure meter I had an amplifier that would read a negative noise figure. I knew at the time that this was categorically impossible. So I looked for reasons. I discovered the reading I got was related to the time I left the hot source on to take a reading. The next time I had to do a low noise figure (2 or so) I used a hot/cold noise source involving liquid nitrogen for cold.)

That design you have looks like it may be better suited to UHF than HF. I notice this from the datasheet.
"For NC300/400 SeriesR = Adjust for performance" Um, how did you adjust it? (And I wonder what they mean by "best performance". Your board design suggests you are meticulous enough to have addressed this issue, of course. Hm, I also wonder if that ceramic cap with long leads has the performance above UHF that you'd want. (Without parts values it's hard to tell what is going on and who the players are. "Who is on first." (Abbot to Costello))

{^_^}

On 20200816 19:06:26, Marcus Ramos wrote:
Hi all;

If we search the web we find several aproaches to measure amp noise figures.

I remember a QEX article which uses an AD8307 as log detector and a NoiseComm diode as ENR source.

At that time I ordered two or three AD8307 and one diode from NCL, not the part listed at QEX article but another type, as far as I recall it is the NC305, that generates 30 to 35dB ENR from 10MHz to 10GHz.

Then I designed a small PCB and did some tests and simulations to create my poor man ENR generator which presents 50 ohm to the load, doesn't matter if on or off state.

After several years missing, I found my small board and it's working. Even below 10MHz it generatea the same baseline hump from 100KHz and above.

Now the HF+ Discovery: -140dBm @ 500Hz MDS means -168dBm @ 1Hz BW. A 6dB NF.

When I wire the small board to Discovery, the baseline at HDSDR rise from lets say -135dBm to -120dBm.

Can I use this setup to evaluate or even measure amplifiers noise figures / gain? Or will I need any extra amplifier / band pass filter before Discovery.

My interest is at HF (high intercept home made Norton amps to my homebrewed 4 port antenna splitters, loop antenna amplifiers, etc).

I read that 4 steps will be necessary and admit I need to read agn and agn =:)

* ENR off, baseline calibration
* ENR on, baseline 2 calibration, ENR source calibration
* ENR off + DUT (only noise)
* ENR on + DUT (gain + noise)

The readings at HDSDR for instance (where sw calculates signal @ 500Hz and at selected resolution BW) after some averages can be trusted when the source is an device such as HF+ Discovery and his built in LNA?

73
Marcus
PY3CRX + PY2PLL




NCL305.jpg




Re: OT: HF+ Discovery as part of a "simple" NF meter

doug
 

I

On 8/17/20 9:23 PM, Marcus Ramos wrote:
Well ...

I still trying to remember why I assemble this source this way. If we take a look at NoiseComm paper, they show the diode from ground to a resitor of *certain* value ... I guess it's used to limit diode current to 8 ... 12mA.

I read some (long) time ago that standard NF meter switches ENR sources with -21V on/off. The attenuator at ENR output have the function to act as a 50 ohm resistor at the room temp.

I remember that I did some simulation with diode S parameters trying to create a constant Z source. The ceramic cap is a last week adition, when testing this source conected to HF+ Discovery I noticed that noise amplitude decreases below 10MHz or so. But adding this cap "solve" this problem, noise was almost flat until 100KHz or so.

At the time of building this ENR source I was more interested in LNAs for EME on 144, 432, 1296 and 2304. Why not 10G? May be another diode fits actual needs. But 30 to 35dB ENR is a lot of noise.
Noise diodes generally put out noise in the vicinity of 30dB or more ENR, but the large degree of attenuation it takes
to get the excess noise power to the vicinity of 15.5dB or even 5dB makes sure that the amplifier under test will always
see a good 50 Ohm source, whether the diode is "fired" or not. (Giving myself away: In the dear old days before solid
state noise diodes, there were "noise tubes"--a device closely related to a fluorescent light bulb--that was given a
high-voltage jolt to start it to conduct, and we would always refer to that as "firing the noise tube." One problem
with those noise tubes and transistor lnas: there was the chance that the spike that fired the tube would damage or
destroy the transistor! It was then necessary to disconnect the DUT from the noise tube while you fired it, and
then connect it up again.) JoAnne, I bet you remember those days!
--doug, WA2SAY retired RF engineer

Could the temp changes on resistor (the attenuator) and diode be the same? They share the same substrat. Ok, diode will sink 12v/10mA=120mW half of the cycle. Need do test.

And - yes - the decoupling harness was a try to create a good decoupling response from 100MHz to 10GHz, takin into accout ESR of those caps and was the result of some simulation at Genesys or other tool ... +15 years ago.

May be better finish the QEX project =:)

73
MR

Em 17/08/2020 09:02, jdow escreveu:
You might get more accurate results injecting a modest signal along with the noise. This was brought home to me when I found myself working in the lab on network control software for the AN/USC-28 DSCS SatCom modem. Apparently the way it was designed you needed an interfering signal to get it to work in the lab. The front end was left off for the test because back to back, even with good attenuators, was too strong. It required some interfering signal for it to work correctly with the normally expected inputs to the receiver post front end gain. Adding a little signal made it work like magic. You get more bits by averaging signals, decimation is one way of doing this. Those extra bits were critical to making it work. They may also prove critical for your measurement effort.

Another thing to consider is the diode heating up. If your noise figure is low a hot 50 ohm resistor will foo your noise figure reading, making it look lower than it is.

With an ancient HP 6AL5 based noise figure meter I had an amplifier that would read a negative noise figure. I knew at the time that this was categorically impossible. So I looked for reasons. I discovered the reading I got was related to the time I left the hot source on to take a reading. The next time I had to do a low noise figure (2 or so) I used a hot/cold noise source involving liquid nitrogen for cold.)

That design you have looks like it may be better suited to UHF than HF. I notice this from the datasheet.
"For NC300/400 SeriesR = Adjust for performance" Um, how did you adjust it? (And I wonder what they mean by "best performance". Your board design suggests you are meticulous enough to have addressed this issue, of course. Hm, I also wonder if that ceramic cap with long leads has the performance above UHF that you'd want. (Without parts values it's hard to tell what is going on and who the players are. "Who is on first." (Abbot to Costello))

{^_^}

On 20200816 19:06:26, Marcus Ramos wrote:
Hi all;

If we search the web we find several aproaches to measure amp noise figures.

I remember a QEX article which uses an AD8307 as log detector and a NoiseComm diode as ENR source.

At that time I ordered two or three AD8307 and one diode from NCL, not the part listed at QEX article but another type, as far as I recall it is the NC305, that generates 30 to 35dB ENR from 10MHz to 10GHz.

Then I designed a small PCB and did some tests and simulations to create my poor man ENR generator which presents 50 ohm to the load, doesn't matter if on or off state.

After several years missing, I found my small board and it's working. Even below 10MHz it generatea the same baseline hump from 100KHz and above.

Now the HF+ Discovery: -140dBm @ 500Hz MDS means -168dBm @ 1Hz BW. A 6dB NF.

When I wire the small board to Discovery, the baseline at HDSDR rise from lets say -135dBm to -120dBm.

Can I use this setup to evaluate or even measure amplifiers noise figures / gain? Or will I need any extra amplifier / band pass filter before Discovery.

My interest is at HF (high intercept home made Norton amps to my homebrewed 4 port antenna splitters, loop antenna amplifiers, etc).

I read that 4 steps will be necessary and admit I need to read agn and agn =:)

* ENR off, baseline calibration
* ENR on, baseline 2 calibration, ENR source calibration
* ENR off + DUT (only noise)
* ENR on + DUT (gain + noise)

The readings at HDSDR for instance (where sw calculates signal @ 500Hz and at selected resolution BW) after some averages can be trusted when the source is an device such as HF+ Discovery and his built in LNA?

73
Marcus
PY3CRX + PY2PLL




NCL305.jpg




Re: Display of an AM signal

James Aiu
 

Thank you Tseug,
Will check it out. 
Stay safe,
J

On Mon, Aug 17, 2020 at 5:24 PM James Aiu via groups.io <aiuj51=gmail.com@groups.io> wrote:
My bad!  Tried to start all over the missing plugin is scytale-C (oops!); got the download at https://www.rtl-sdr.com/scytale-c-a-new-inmarsat-std-c-decoder-tekmanoid-std-c-decoder-updates/  extracted to in the folder.  installed file "install-rtlsdr" bat file and it installed.  Clicked on SDRSharp.exe and  it installed.  Program recognizes airspy mini with ss#. all seem to work I get static noises but receives no signals. Any links to get information on setting the receiver?
Thank you once more.j
Stay safe
  

--


Re: OT: HF+ Discovery as part of a "simple" NF meter

Marcus Ramos
 

Well ...

I still trying to remember why I assemble this source this way. If we take a look at NoiseComm paper, they show the diode from ground to a resitor of *certain* value ... I guess it's used to limit diode current to 8 ... 12mA.

I read some (long) time ago that standard NF meter switches ENR sources with -21V on/off. The attenuator at ENR output have the function to act as a 50 ohm resistor at the room temp.

I remember that I did some simulation with diode S parameters trying to create a constant Z source. The ceramic cap is a last week adition, when testing this source conected to HF+ Discovery I noticed that noise amplitude decreases below 10MHz or so. But adding this cap "solve" this problem, noise was almost flat until 100KHz or so.

At the time of building this ENR source I was more interested in LNAs for EME on 144, 432, 1296 and 2304. Why not 10G? May be another diode fits actual needs. But 30 to 35dB ENR is a lot of noise.

Could the temp changes on resistor (the attenuator) and diode be the same? They share the same substrat. Ok, diode will sink 12v/10mA=120mW half of the cycle. Need do test.

And - yes - the decoupling harness was a try to create a good decoupling response from 100MHz to 10GHz, takin into accout ESR of those caps and was the result of some simulation at Genesys or other tool ... +15 years ago.

May be better finish the QEX project =:)

73
MR

Em 17/08/2020 09:02, jdow escreveu:

You might get more accurate results injecting a modest signal along with the noise. This was brought home to me when I found myself working in the lab on network control software for the AN/USC-28 DSCS SatCom modem. Apparently the way it was designed you needed an interfering signal to get it to work in the lab. The front end was left off for the test because back to back, even with good attenuators, was too strong. It required some interfering signal for it to work correctly with the normally expected inputs to the receiver post front end gain. Adding a little signal made it work like magic. You get more bits by averaging signals, decimation is one way of doing this. Those extra bits were critical to making it work. They may also prove critical for your measurement effort.

Another thing to consider is the diode heating up. If your noise figure is low a hot 50 ohm resistor will foo your noise figure reading, making it look lower than it is.

With an ancient HP 6AL5 based noise figure meter I had an amplifier that would read a negative noise figure. I knew at the time that this was categorically impossible. So I looked for reasons. I discovered the reading I got was related to the time I left the hot source on to take a reading. The next time I had to do a low noise figure (2 or so) I used a hot/cold noise source involving liquid nitrogen for cold.)

That design you have looks like it may be better suited to UHF than HF. I notice this from the datasheet.
"For NC300/400 SeriesR = Adjust for performance" Um, how did you adjust it? (And I wonder what they mean by "best performance". Your board design suggests you are meticulous enough to have addressed this issue, of course. Hm, I also wonder if that ceramic cap with long leads has the performance above UHF that you'd want. (Without parts values it's hard to tell what is going on and who the players are. "Who is on first." (Abbot to Costello))

{^_^}

On 20200816 19:06:26, Marcus Ramos wrote:
Hi all;

If we search the web we find several aproaches to measure amp noise figures.

I remember a QEX article which uses an AD8307 as log detector and a NoiseComm diode as ENR source.

At that time I ordered two or three AD8307 and one diode from NCL, not the part listed at QEX article but another type, as far as I recall it is the NC305, that generates 30 to 35dB ENR from 10MHz to 10GHz.

Then I designed a small PCB and did some tests and simulations to create my poor man ENR generator which presents 50 ohm to the load, doesn't matter if on or off state.

After several years missing, I found my small board and it's working. Even below 10MHz it generatea the same baseline hump from 100KHz and above.

Now the HF+ Discovery: -140dBm @ 500Hz MDS means -168dBm @ 1Hz BW. A 6dB NF.

When I wire the small board to Discovery, the baseline at HDSDR rise from lets say -135dBm to -120dBm.

Can I use this setup to evaluate or even measure amplifiers noise figures / gain? Or will I need any extra amplifier / band pass filter before Discovery.

My interest is at HF (high intercept home made Norton amps to my homebrewed 4 port antenna splitters, loop antenna amplifiers, etc).

I read that 4 steps will be necessary and admit I need to read agn and agn =:)

* ENR off, baseline calibration
* ENR on, baseline 2 calibration, ENR source calibration
* ENR off + DUT (only noise)
* ENR on + DUT (gain + noise)

The readings at HDSDR for instance (where sw calculates signal @ 500Hz and at selected resolution BW) after some averages can be trusted when the source is an device such as HF+ Discovery and his built in LNA?

73
Marcus
PY3CRX + PY2PLL




NCL305.jpg



Re: YouLoop Amplifier - Progress ??

Phil EVG <phil@...>
 



The YouLoop Antenna revisted
A plain vanilla Shielded Mobius Loop with an elegant low cost mechanical solution being sold by  Airspy, at a cost lower than one can buy the components for a DIY copy
It was designed for use as Passive Loop for SDR and radios that have Waterfall / Panadapter Radios. Every loop has a Resonant Frequency, but it is not all that relevant in a wide band application.  
Consider the use of ultra low noise Coax and Common Mode Chokes
The YouLoop is eligible for an Active Loop application, Airspy has a design effort on the back burner.  For those interested there several low cost solutions.
PCBoard RF Amplifiers from eBay, Amazon Ali Express etc....
Marrying the low cost SDR oriented Active Loop antennas like the MLA-30 and its variants. If one does be aware of simple mods like the ultra low noise Coax for the down lead and the use of Common Mode Chokes.  
MLA 30 and Variants
Y-200A Active Loop Receiving Antenna Short Wave 100KHz-180MHz for SDR Radio  
Active Loop Antenna MLA-30+ Plus  
 100KHz-30MHz Loop Active Antenna Small For Shortwave Radio Clearer Sound
Active Loop Antenna Small Loop Active Receiving Antenna  
Active Loop Antenna 2020 K-180WLA  
73 de jordan ve7jjd 


 Y-200A Active Loop Receiving Antenna Short Wave 100KHz-180MHz for SDR Radio  https://www.ebay.ca/itm/Y-200A-Active-Loop-Receiving-Antenna-Short-Wave-100KHz-180MHz-for-SDR-Radio/174347407661?hash=item2897ea512d:g:nAkAAOSw5sBfDAz2
Active Loop Antenna MLA-30+ Plus  https://www.ebay.ca/itm/100KHz-30MHz-Active-Loop-Antenna-Active-Receiving-Antenna-for-Medium-Wave-Radio/383057752478?_trkparms=aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D20131003132420%26meid%3D0a02ab2721a34566a7172e85826e762b%26pid%3D100005%26rk%3D10%26rkt%3D12%26mehot%3Dpf%26sd%3D383497301275%26itm%3D383057752478%26pmt%3D1%26noa%3D0%26pg%3D2047675%26algv%3DSimplAMLv5PairwiseWebWithBBEV1Filter%26brand%3DUnbranded&_trksid=p2047675.c100005.m1851
100KHz-30MHz Loop Active Antenna Small For Shortwave Radio Clearer Sound https://www.ebay.ca/itm/100KHz-30MHz-Loop-Active-Antenna-Small-For-Shortwave-Radio-Clearer-Sound/383497301275?_trkparms=aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D20131003132420%26meid%3Da45a3d5858d04af386122e0e7ebb5db0%26pid%3D100005%26rk%3D4%26rkt%3D12%26mehot%3Dpf%26sd%3D283840739957%26itm%3D383497301275%26pmt%3D1%26noa%3D0%26pg%3D2047675%26algv%3DSimplAMLv5PairwiseWebWithBBEV1Filter%26brand%3DUnbranded&_trksid=p2047675.c100005.m1851
Active Loop Antenna Small Loop Active Receiving Antenna  https://www.ebay.ca/itm/Small-Loop-Active-Receiving-Antenna-100KHz-30MHz-For-Short-Medium-Wave-Radio/283840739957?_trkparms=aid%3D1110010%26algo%3DHOMESPLICE.DISCCARDS%26ao%3D1%26asc%3D20200220090753%26meid%3Dfddfb6123e68476084909b92bd805769%26pid%3D100009%26rk%3D1%26rkt%3D1%26sd%3D283934319573%26itm%3D283840739957%26pmt%3D1%26noa%3D0%26pg%3D2047675%26algv%3Ddefault%26brand%3DUnbranded&_trksid=p2047675.c100009.m1982
Active Loop Antenna 2020 K-180WLA
https://www.ebay.ca/itm/2020-K-180WLA-Active-Loop-Broadband-Receiving-Antenna-0-1M-180MHz-For-SDR-Radio/143558130215?_trkparms=aid%3D1110009%26algo%3DSPLICE.COMPLISTINGS%26ao%3D1%26asc%3D20200220094952%26meid%3D4e6b4ca744d94292be239315f65dede8%26pid%3D100008%26rk%3D2%26rkt%3D12%26mehot%3Dpp%26sd%3D283934319573%26itm%3D143558130215%26pmt%3D1%26noa%3D0%26pg%3D2047675%26algv%3Ddefault%26brand%3DUnbranded&_trksid=p2047675.c100008.m2219


Re: Display of an AM signal

James Aiu
 

My bad!  Tried to start all over the missing plugin is scytale-C (oops!); got the download at https://www.rtl-sdr.com/scytale-c-a-new-inmarsat-std-c-decoder-tekmanoid-std-c-decoder-updates/  extracted to in the folder.  installed file "install-rtlsdr" bat file and it installed.  Clicked on SDRSharp.exe and  it installed.  Program recognizes airspy mini with ss#. all seem to work I get static noises but receives no signals. Any links to get information on setting the receiver?
Thank you once more.j
Stay safe
  


Re: AIRSPY SDR software for Macosx #software

andrea ottaviani
 

Good morning. 
I found it useful to disable the power saving of the USB ports.
I attach photos.
Good luck de IK0MMI andrea
 


Re: Display of an AM signal

tseug
 

James
Do you mean a plugin to interface with scytalec?
If so, you will find it and documentation at:
https://bitbucket.org/scytalec/scytalec/downloads/


Re: YouLoop Amplifier - Progress ??

David Eckhardt
 

If you are so anxious for a 'turn-key' preamplifier, go build one for  yourself.  I suspect it will cause the S-Meter to jump around much more, but won't improve (S+N) / N) much, if at all.  They're also very inexpensive on ePay.

Dave - WØLEV


On Mon, Aug 17, 2020 at 9:52 AM Ron Liekens <r.e.liekens@...> wrote:
John,

The YouLoop does not need an amplifier. I made a YouLoop with an amplifier and it did not offered me any better results. The problem with the IC-7300 is that it has a poor waterfall. I know and have experienced this from when I started to use the IC-7300 beside my SDR receivers on SDRconsole.

The YouLoop offers a good SNR and that is what counts. Do not stare you blind on the low signal level of the S-meter. I made several test with the YouLoop in several different setups with mostly different equipment. As long as the noise level rises by 5 dB when you connect the YouLoop to the IC-7300 an amplifier will not give you better reception on HF. VHF/UHF and SHF are a different kettle of fish of coarse.

73' Ron
ON2RON



--
Dave - WØLEV
Just Let Darwin Work


Re: Display of an AM signal

wbarroso@...
 

Fantastic, Good luck !!
joe b.


Re: YouLoop Amplifier - Progress ??

jdow
 



On 20200817 02:51:54, Ron Liekens wrote:
John,

The YouLoop does not need an amplifier. I made a YouLoop with an amplifier and it did not offered me any better results. The problem with the IC-7300 is that it has a poor waterfall. I know and have experienced this from when I started to use the IC-7300 beside my SDR receivers on SDRconsole.

The YouLoop offers a good SNR and that is what counts. Do not stare you blind on the low signal level of the S-meter. I made several test with the YouLoop in several different setups with mostly different equipment. As long as the noise level rises by 5 dB when you connect the YouLoop to the IC-7300 an amplifier will not give you better reception on HF. VHF/UHF and SHF are a different kettle of fish of coarse.

73' Ron
ON2RON

You have no idea how refreshing your 5 dB comment above makes me feel. At least ONE other person "gets it."

{^_-}


Re: OT: HF+ Discovery as part of a "simple" NF meter

jdow
 

You might get more accurate results injecting a modest signal along with the noise. This was brought home to me when I found myself working in the lab on network control software for the AN/USC-28 DSCS SatCom modem. Apparently the way it was designed you needed an interfering signal to get it to work in the lab. The front end was left off for the test because back to back, even with good attenuators, was too strong. It required some interfering signal for it to work correctly with the normally expected inputs to the receiver post front end gain. Adding a little signal made it work like magic. You get more bits by averaging signals, decimation is one way of doing this. Those extra bits were critical to making it work. They may also prove critical for your measurement effort.

Another thing to consider is the diode heating up. If your noise figure is low a hot 50 ohm resistor will foo your noise figure reading, making it look lower than it is.

With an ancient HP 6AL5 based noise figure meter I had an amplifier that would read a negative noise figure. I knew at the time that this was categorically impossible. So I looked for reasons. I discovered the reading I got was related to the time I left the hot source on to take a reading. The next time I had to do a low noise figure (2 or so) I used a hot/cold noise source involving liquid nitrogen for cold.)

That design you have looks like it may be better suited to UHF than HF. I notice this from the datasheet.
"For NC300/400 SeriesR = Adjust for performance" Um, how did you adjust it? (And I wonder what they mean by "best performance". Your board design suggests you are meticulous enough to have addressed this issue, of course. Hm, I also wonder if that ceramic cap with long leads has the performance above UHF that you'd want. (Without parts values it's hard to tell what is going on and who the players are. "Who is on first." (Abbot to Costello))

{^_^}

On 20200816 19:06:26, Marcus Ramos wrote:
Hi all;

If we search the web we find several aproaches to measure amp noise figures.

I remember a QEX article which uses an AD8307 as log detector and a NoiseComm diode as ENR source.

At that time I ordered two or three AD8307 and one diode from NCL, not the part listed at QEX article but another type, as far as I recall it is the NC305, that generates 30 to 35dB ENR from 10MHz to 10GHz.

Then I designed a small PCB and did some tests and simulations to create my poor man ENR generator which presents 50 ohm to the load, doesn't matter if on or off state.

After several years missing, I found my small board and it's working. Even below 10MHz it generatea the same baseline hump from 100KHz and above.

Now the HF+ Discovery: -140dBm @ 500Hz MDS means -168dBm @ 1Hz BW. A 6dB NF.

When I wire the small board to Discovery, the baseline at HDSDR rise from lets say -135dBm to -120dBm.

Can I use this setup to evaluate or even measure amplifiers noise figures / gain? Or will I need any extra amplifier / band pass filter before Discovery.

My interest is at HF (high intercept home made Norton amps to my homebrewed 4 port antenna splitters, loop antenna amplifiers, etc).

I read that 4 steps will be necessary and admit I need to read agn and agn =:)

* ENR off, baseline calibration
* ENR on, baseline 2 calibration, ENR source calibration
* ENR off + DUT (only noise)
* ENR on + DUT (gain + noise)

The readings at HDSDR for instance (where sw calculates signal @ 500Hz and at selected resolution BW) after some averages can be trusted when the source is an device such as HF+ Discovery and his built in LNA?

73
Marcus
PY3CRX + PY2PLL




NCL305.jpg


Re: YouLoop Amplifier - Progress ??

prog
 

On Fri, Aug 14, 2020 at 02:24 PM, John Dusek wrote:
Has there been any progress in developing the amplifier that Prog posted about back in March?
Many early prototypes are in the field (US, UK, JP, NZ) with wildly different signal situations. As this is not the main development effort of the moment, things can be slower than usual, but not stopped. The next iteration will lower the gain, improve the MDS and the linearity. As usual, things will be released when we are happy with them.
Thanks for asking!


Re: YouLoop Amplifier - Progress ??

Ron Liekens
 

John,

The YouLoop does not need an amplifier. I made a YouLoop with an amplifier and it did not offered me any better results. The problem with the IC-7300 is that it has a poor waterfall. I know and have experienced this from when I started to use the IC-7300 beside my SDR receivers on SDRconsole.

The YouLoop offers a good SNR and that is what counts. Do not stare you blind on the low signal level of the S-meter. I made several test with the YouLoop in several different setups with mostly different equipment. As long as the noise level rises by 5 dB when you connect the YouLoop to the IC-7300 an amplifier will not give you better reception on HF. VHF/UHF and SHF are a different kettle of fish of coarse.

73' Ron
ON2RON


OT: HF+ Discovery as part of a "simple" NF meter

Marcus Ramos
 

Hi all;

If we search the web we find several aproaches to measure amp noise figures.

I remember a QEX article which uses an AD8307 as log detector and a NoiseComm diode as ENR source.

At that time I ordered two or three AD8307 and one diode from NCL, not the part listed at QEX article but another type, as far as I recall it is the NC305, that generates 30 to 35dB ENR from 10MHz to 10GHz.

Then I designed a small PCB and did some tests and simulations to create my poor man ENR generator which presents 50 ohm to the load, doesn't matter if on or off state.

After several years missing, I found my small board and it's working. Even below 10MHz it generatea the same baseline hump from 100KHz and above.

Now the HF+ Discovery: -140dBm @ 500Hz MDS means -168dBm @ 1Hz BW. A 6dB NF.

When I wire the small board to Discovery, the baseline at HDSDR rise from lets say -135dBm to -120dBm.

Can I use this setup to evaluate or even measure amplifiers noise figures / gain? Or will I need any extra amplifier / band pass filter before Discovery.

My interest is at HF (high intercept home made Norton amps to my homebrewed 4 port antenna splitters, loop antenna amplifiers, etc).

I read that 4 steps will be necessary and admit I need to read agn and agn =:)

* ENR off, baseline calibration
* ENR on, baseline 2 calibration, ENR source calibration
* ENR off + DUT (only noise)
* ENR on + DUT (gain + noise)

The readings at HDSDR for instance (where sw calculates signal @ 500Hz and at selected resolution BW) after some averages can be trusted when the source is an device such as HF+ Discovery and his built in LNA?

73
Marcus
PY3CRX + PY2PLL


Re: Display of an AM signal

Edward MacDonald
 

I am not the author of the scope view plugins, but I am working at this moment on a new scope view plugin of my own  design for SDR# which will host some new features as well, including the ability to have up to three traces on the scope at the same time, markers, measurements and some other stuff. Should be done in 2 to 3 weeks.


On Sun., Aug. 16, 2020, 2:04 p.m. , <wbarroso@...> wrote:
I am not familiar with the spytateC plugin.. does this plug in show a scope view? there used to be a scope view that showed modulation, but after
SDR# upgraded its basic operating platform, some of the plugins stopped working. Some of the plugins were also updated to work with SDR# but not all have been updated.
the basic version of "scopeview" was updated, but not improved version of scopeview,  I am hoping that will also upgraded to work with our new version of SDR#.


Re: Display of an AM signal

wbarroso@...
 

I am not familiar with the spytateC plugin.. does this plug in show a scope view? there used to be a scope view that showed modulation, but after
SDR# upgraded its basic operating platform, some of the plugins stopped working. Some of the plugins were also updated to work with SDR# but not all have been updated.
the basic version of "scopeview" was updated, but not improved version of scopeview,  I am hoping that will also upgraded to work with our new version of SDR#.


Re: AIRSPY SDR software for Macosx #software

John Brown
 

The timeout is unique to the Airspy HF+ (so far). I also have an SDRplay RSPdx and installed the software SDRuno and drivers for it. Went well. Brought the RSPdx up under both Uno and then SDRconsole. It's still running after an hour. 

The RSPdx installs drivers. The HF+ does not. Could that be the difference? Are there drivers that might make a difference? So far as I can see the drivers in use on the USB while running the HF+ are plain vanilla Windows from 2009 or so.

--
John


Re: Display of an AM signal

James Aiu
 

I am not computer savy! How do I add the plugin? Cant' find SpytateC Plugin.  It's not in the zip file extract.
Thank you for your input.
J


Re: Display of an AM signal

wbarroso@...
 

i believe that the inverse of the FFT display (waterfall) would be the time domain display,  is this possible add to a plugin ??
thanx

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