Date   
Re: Using SDR# and HF+ for FM modulator measurement #airspyhfplus #sdrsharp

Peter Jönsson
 

I think you can change deemphasis in SDRSharp.exe.Config.
Look at the line <add key="deemphasisTime" value="50" />

Re: Noise Floor With And Without Antenna #airspyhfplus

jdow
 

They don't look out of place. But I suspect you're not thinking in SDR terms vs analog terms. The HF+ also has agc aboard. So unless the AGC setting is continuously polled and adjusted for the noise floor may change, it may pump, it may do other surprising things. HF noise is NOT, repeat NOT, going to approach 50 ohm dummy load ktB noise.

Compare signal to noise ratios. They are what matter.
{^_^}

On 20180223 02:25, markobyrnes@... wrote:
Lol yes I made a mistake with the pics, I simply edited the text so should represent the correct pics now.
AGC and preamp off make no difference.
What about the noise floor with no antenna ?
And what do people think of the noise floor of my Kiwi with the loop ? just so I can have something to go by.
http://emeraldsdr.ddns.net:8073/

Re: Noise Floor With And Without Antenna #airspyhfplus

EI3IBB Mark
 

Lol yes I made a mistake with the pics, I simply edited the text so should represent the correct pics now. 

AGC and preamp off make no difference. 

What about the noise floor with no antenna ?

And what do people think of the noise floor of my Kiwi with the loop ? just so I can have something to go by.

http://emeraldsdr.ddns.net:8073/

Re: Using SDR# and HF+ for FM modulator measurement #airspyhfplus #sdrsharp

Moij2x
 

For short conclusion of deemphasis, is it 50uS on HF+SDR# and not changeable by user?

Is any good alternative available for TCP_server plugin/TCP pipe?

Re: Using SDR# and HF+ for FM modulator measurement #airspyhfplus #sdrsharp

prog
 

On Thu, Feb 22, 2018 at 10:34 pm, jdow wrote:
Only if you turn on audio effects. Turn them off and it's pretty good. (It's still PC audio, which is about 10 dB shy of professional audio levels.)

{^_^}
The Windows resampler is terrible - effects or not.

Re: Using SDR# and HF+ for FM modulator measurement #airspyhfplus #sdrsharp

jdow
 

Only if you turn on audio effects. Turn them off and it's pretty good. (It's still PC audio, which is about 10 dB shy of professional audio levels.)

{^_^}

On 20180222 07:34, prog wrote:
On Thu, Feb 22, 2018 at 07:08 am, Moij2x wrote:
First tool I find what was able to connect softwares in PC.
What is better way to connect SDR# to REW inside PC?
For this kind of measurements the only way to make sure the samples sent by SDR# are actually received unaltered by your app is to use a TCP pipe <https://www.rtl-sdr.com/new-audio-streaming-tcp-server-plugin-for-sdr/>. The output sample rate of SDR# with the HF+ in FM is 48 ksps. If there is any resampling involved in the chain, it could deteriorate the quality. And it is known that the Windows resampler, and the Windows "Audio Mixer" in general have quality problems.
<http://archimago.blogspot.fr/2015/11/measurements-windows-10-audio-stack.html>

Re: #airspyhfplus #airspyhfplus

VE7KED
 

TEST 2 End of day results - AGC On, Threshold High, Preamp Off

Winner  is the HF+ at 36264 decodes

RSP2Pro 35956 (99.15%)
7610 - 29240 (80.63%)
9100 - 26279 (73.09%)


I will be commencing TEST 3 for the next 24 hours - AGC On, Threshold Low, Preamp On

Re: Using SDR# and HF+ for FM modulator measurement #airspyhfplus #sdrsharp

Dana Myers
 

On 2/22/2018 6:27 PM, jdow wrote:
The KT-6040 would have deemphasis to compensate for the modulator's preemphasis. (It's done that way for the FM demodulator noise characteristics.
That, and the historical use of PM with an inherent +6dB/octave response
before direct-FM became common.

Dana  K6JQ

Re: Noise Floor With And Without Antenna #airspyhfplus

jdow
 

And even THAT will not show a good noise floor. SDRs do not behave exactly the same as analog receivers with regards to noise, especially when decimation is involved.
{^_^}

On 20180222 17:38, David Eckhardt wrote:
Also, the 'without antenna' should be terminated with a good non-reactive 50-ohm load.
On Fri, Feb 23, 2018 at 1:37 AM, David Eckhardt <davearea51a@... <mailto:davearea51a@...>> wrote:
Run the same with AGC OFF and preamp OFF.  Please let us know what the
bandwidth is.  Also, the 20-meters capture is still 49-meters by the
frequency indication.  You shouldn't need the preamp for HF with a
'reasonable' antenna.
Dave - WØLEV
On Thu, Feb 22, 2018 at 7:48 PM, <markobyrnes@...
<mailto:markobyrnes@...>> wrote:
First Pic , 49 meters with Bonito FX Loop. A few screen shots from about
5 pm UTC which is local time same as GMT.
2nd Pic, without Antenna connected. What do people think of this noise
floor ?
20 Meters Ham With Loop.
--
*Dave - WØLEV
*
*/Just Let Darwin Work/*
--
*Dave - WØLEV
*
*/Just Let Darwin Work/*

Re: Noise Floor With And Without Antenna #airspyhfplus

jdow
 

It appears that the top pix is 14 MHz and the bottom two are 6 MHz. He apparently sent the wrong pictures.
{^_^}

On 20180222 17:37, David Eckhardt wrote:
Run the same with AGC OFF and preamp OFF.  Please let us know what the bandwidth is.  Also, the 20-meters capture is still 49-meters by the frequency indication.  You shouldn't need the preamp for HF with a 'reasonable' antenna.
Dave - WØLEV
On Thu, Feb 22, 2018 at 7:48 PM, <markobyrnes@... <mailto:markobyrnes@...>> wrote:
First Pic , 49 meters with Bonito FX Loop. A few screen shots from about 5
pm UTC which is local time same as GMT.
2nd Pic, without Antenna connected. What do people think of this noise floor ?
20 Meters Ham With Loop.
--
*Dave - WØLEV
*
*/Just Let Darwin Work/*

Re: Noise Floor With And Without Antenna #airspyhfplus

jdow
 

Wrong pictures.
{^_^}

On 20180222 11:48, markobyrnes@... wrote:
First Pic , 49 meters with Bonito FX Loop. A few screen shots from about 5 pm UTC which is local time same as GMT.
2nd Pic, without Antenna connected. What do people think of this noise floor ?
20 Meters Ham With Loop.

Re: Using SDR# and HF+ for FM modulator measurement #airspyhfplus #sdrsharp

jdow
 

The KT-6040 would have deemphasis to compensate for the modulator's preemphasis. (It's done that way for the FM demodulator noise characteristics. Noise is higher with higher frequencies. So you emphasize the treble spectrum before transmission and deemphasize it on reception to make it flat again. It's almost as if your Tx toy has double pre-emphasis presuming the Kenwood is built correctly. (And I suspect Youssef's code is correct at least for Europe. I do not see an adjustment for the US/SouK anomaly. Nor did I notice an adjustment for deemphasis on or off. I do remember adding it to my customized SDRSharp from when source was available. I use that for my background FM listening since it has a fail safe RDS decoder which works despite slightly defective transmitters. Before I added the deemphasis SDRSharp was rather harsh on the "sort of high frequencies" my ear works with theses days. Is there REALLY sound past 4 kHz? There used to be....)

{^_^}

On 20180222 05:21, Moij2x wrote:
On Thu, Feb 22, 2018 at 01:58 am, jdow wrote:
It looks like the preemphasis curve does not come close to matching the
deemphasis curve in the receiver. It looks like you have it turned off in
the receiver.
This is good hint.
I believe my KT-6040 had European 50uS de-emphasis and it can be changed only in hardware, no settings existing for that on device control panel.
I not find any FM de-emphasis settings on HF+SDR#, but I think it is also 50uS.
Measured FM-modulator is no-name, no any information available for it, but guessing by SPL curves, it seems have 75 uS pre-emphasis.

Re: Noise Floor With And Without Antenna #airspyhfplus

David Eckhardt
 

Also, the 'without antenna' should be terminated with a good non-reactive 50-ohm load. 

On Fri, Feb 23, 2018 at 1:37 AM, David Eckhardt <davearea51a@...> wrote:
Run the same with AGC OFF and preamp OFF.  Please let us know what the bandwidth is.  Also, the 20-meters capture is still 49-meters by the frequency indication.  You shouldn't need the preamp for HF with a 'reasonable' antenna. 

Dave - WØLEV

On Thu, Feb 22, 2018 at 7:48 PM, <markobyrnes@...> wrote:
First Pic , 49 meters with Bonito FX Loop. A few screen shots from about 5 pm UTC which is local time same as GMT.




2nd Pic, without Antenna connected. What do people think of this noise floor ?





20 Meters Ham With Loop.






--
Dave - WØLEV
Just Let Darwin Work



--
Dave - WØLEV
Just Let Darwin Work

Re: Noise Floor With And Without Antenna #airspyhfplus

David Eckhardt
 

Run the same with AGC OFF and preamp OFF.  Please let us know what the bandwidth is.  Also, the 20-meters capture is still 49-meters by the frequency indication.  You shouldn't need the preamp for HF with a 'reasonable' antenna. 

Dave - WØLEV

On Thu, Feb 22, 2018 at 7:48 PM, <markobyrnes@...> wrote:
First Pic , 49 meters with Bonito FX Loop. A few screen shots from about 5 pm UTC which is local time same as GMT.




2nd Pic, without Antenna connected. What do people think of this noise floor ?





20 Meters Ham With Loop.






--
Dave - WØLEV
Just Let Darwin Work

Re: Jumpy FFT Display with SDR# R1651

Ian DXer
 

You're right, this kind of fault is similar to a faulty antenna connection & that was
one of the first things that came to mind (and checked), but the fault was specific to or noted only with recent software
changes to SDR# and not happening on all freqs. 
Youssef is like an Olympic sprinter at rapidly resolving these bugs. Fixed with release 1653 of SDR#.
Many thanks for your time PMM :-)

Re: Jumpy FFT Display with SDR# R1651

Ian DXer
 

Downloaded SDR# r1653 & tested briefly.
Yes problem now resolved Youssef - thanks so much, very impressed  :-)

Cheers.

Re: Jumpy FFT Display with SDR# R1651

PMM
 

I have tried to replicate this myself and failed myself, I have seen that behaviour but usually as an impedance error i.e antenna not 50ohm or local interference raising the noise floor, but i think the latter can be ruled out as it should not increase the genuine signal. I would check your antenna connections make sure the ground connect is good.

Inline images 1

On 22 February 2018 at 21:14, Ian DXer <baxterinoz@...> wrote:
Hi Youssef,

Ok shorter msg & I'll try to be as specific as possible:

SETTINGS: 'DEFAULT' (ie/eg. just unzipped r1651 & tried for first time with just frequency changed)
Test Sample Freq: 105.1MHz - very weak signal near strong 150kW signal 104.9MHz. WFM. Also added time stamps...
See image below where I highlight roughly (in yellow the range of the jitter/random jumping of the signal levels.
In this sample outside of 768kHz passpand. noise jumping 15dB. Within passband noise/signals maybe jumping 3dB.
The jumping occurs perhaps 3 times a second - can't be exact.

IMPORTANT: Did some further experimenting, this time with FFT display resolution settings (given your recent work in this area)
& noted that the problem is only evident with FFT Display RESOLUTION settings of 32768 & lower.
The jumping of noise/signals is particularly distracting with 32768 & 16384 settings. The default program setting is of course 32768.

Is this information useful to you Youssef? I have no idea what other setting info I could provide that would be helpful, as it's all basically default settings.

Please let me know if you need further info.



 

Attachments:


Re: Jumpy FFT Display with SDR# R1651

prog
 

On Thu, Feb 22, 2018 at 01:14 pm, Ian DXer wrote:
Ok shorter msg & I'll try to be as specific as possible:
Good. Thanks. Check the latest SDR#.

Re: Jumpy FFT Display with SDR# R1651

Ian DXer
 

Hi Youssef,

Ok shorter msg & I'll try to be as specific as possible:

SETTINGS: 'DEFAULT' (ie/eg. just unzipped r1651 & tried for first time with just frequency changed)
Test Sample Freq: 105.1MHz - very weak signal near strong 150kW signal 104.9MHz. WFM. Also added time stamps...
See image below where I highlight roughly (in yellow the range of the jitter/random jumping of the signal levels.
In this sample outside of 768kHz passpand. noise jumping 15dB. Within passband noise/signals maybe jumping 3dB.
The jumping occurs perhaps 3 times a second - can't be exact.

IMPORTANT: Did some further experimenting, this time with FFT display resolution settings (given your recent work in this area)
& noted that the problem is only evident with FFT Display RESOLUTION settings of 32768 & lower.
The jumping of noise/signals is particularly distracting with 32768 & 16384 settings. The default program setting is of course 32768.

Is this information useful to you Youssef? I have no idea what other setting info I could provide that would be helpful, as it's all basically default settings.

Please let me know if you need further info.



 

Re: Noise Floor With And Without Antenna #airspyhfplus

EI3IBB Mark
 

I'm beginning to think the RG 58 I have is shit, the screen isn't so good looking with foil ? should have taken a pic of it, it's very hard to strip it back without removing half the screen.