HF+ vs NetSDR Comparison


Simon Brown
 

So,

 

Done properly (or at least better) this time: http://sdr-radio.com/AirspyHFPlus

 

Simon Brown, G4ELI
www.sdr-radio.com

 


Joe M.
 

Correct me if I'm wrong, but that looks like 10 dB lower noise
floor AND 10 dB more signal. (a 20 dB overall gain in range)

Joe M.

On 9/28/2017 5:43 PM, Simon Brown wrote:
So,

Done properly (or at least better) this time:
http://sdr-radio.com/AirspyHFPlus

Simon Brown, G4ELI
www.sdr-radio.com


Simon Brown
 

Which comparison?

Simon Brown, G4ELI
www.sdr-radio.com

-----Original Message-----
From: main@airspy.groups.io [mailto:main@airspy.groups.io] On Behalf Of Joe
M.
Sent: 28 September 2017 22:57
To: main@airspy.groups.io
Subject: Re: [airspy] HF+ vs NetSDR Comparison

Correct me if I'm wrong, but that looks like 10 dB lower noise floor AND 10
dB more signal. (a 20 dB overall gain in range)

Joe M.

On 9/28/2017 5:43 PM, Simon Brown wrote:
So,

Done properly (or at least better) this time:
http://sdr-radio.com/AirspyHFPlus

Simon Brown, G4ELI
www.sdr-radio.com


David Eckhardt
 

I'm guessing you refer to the VLF non-directional beacon plots.  Remember, its not about absolute levels but (S+N)/N ratios.

Dave - WØLEV 

On Thu, Sep 28, 2017 at 4:01 PM, Simon Brown <simon@...> wrote:
Which comparison?

Simon Brown, G4ELI
www.sdr-radio.com

-----Original Message-----
From: main@airspy.groups.io [mailto:main@airspy.groups.io] On Behalf Of Joe
M.
Sent: 28 September 2017 22:57
To: main@airspy.groups.io
Subject: Re: [airspy] HF+ vs NetSDR Comparison

Correct me if I'm wrong, but that looks like 10 dB lower noise floor AND 10
dB more signal. (a 20 dB overall gain in range)

Joe M.

On 9/28/2017 5:43 PM, Simon Brown wrote:
> So,
>
> Done properly (or at least better) this time:
> http://sdr-radio.com/AirspyHFPlus
>
> Simon Brown, G4ELI
> www.sdr-radio.com










--
Dave - WØLEV
Just Let Darwin Work


Joe M.
 

Ahhh... I didn't see there were multiples. The first one (VLF).

The others are more of a trade-off. 10 dB lower noise floor and signal.

Still, quite a respectable performance against a unit that costs around 10 times more.

Joe M.

On 9/28/2017 6:01 PM, Simon Brown wrote:
Which comparison?

Simon Brown, G4ELI
www.sdr-radio.com

-----Original Message-----
From: main@airspy.groups.io [mailto:main@airspy.groups.io] On Behalf Of Joe
M.
Sent: 28 September 2017 22:57
To: main@airspy.groups.io
Subject: Re: [airspy] HF+ vs NetSDR Comparison

Correct me if I'm wrong, but that looks like 10 dB lower noise floor AND 10
dB more signal. (a 20 dB overall gain in range)

Joe M.

On 9/28/2017 5:43 PM, Simon Brown wrote:
So,

Done properly (or at least better) this time:
http://sdr-radio.com/AirspyHFPlus

Simon Brown, G4ELI
www.sdr-radio.com






---
This email has been checked for viruses by AVG.
http://www.avg.com


Roberto Zinelli
 

Thank you Simon, nice comparison.  Sure HF+ my next sdr.

Inviato da OldPhone

Il giorno 28 set 2017, alle ore 23:43, Simon Brown <simon@...> ha scritto:

So,

 

Done properly (or at least better) this time: http://sdr-radio.com/AirspyHFPlus

 

Simon Brown, G4ELI
www.sdr-radio.com

 


prog
 

You are most likely confusing the "dBm" scale with the actual noise floor (Check the MDS in the spec sheet). There are only two things to check in these screenshots:
* SNR => A slight advantage for the HF+
* Overloading => also a slight advantage for the HF+


Joe F. KC8RKL
 

Hello all-

At http://sdr-radio.com/AirspyHFPlus

With regard to the NDB band comparision- when I click on the two 'thumbnails' to pull up more detailed screenshots, the HF+ screenshot is taken at 21:05:38 while the NetSDR screenshot is at 22:04:02. Signal and noise levels in the NDB band can vary quite a bit in that amount of time. Probably due to a file naming hiccup during webpage creation.

73,

Joe F. KC8RKL


Simon Brown
 

OK,

 

Let me check this – they were taken at the same time – looks like I have a wrong link, will fix this.

 

Simon Brown, G4ELI
www.sdr-radio.com

 

From: main@airspy.groups.io [mailto:main@airspy.groups.io] On Behalf Of Joe
Sent: 29 September 2017 15:41
To: main@airspy.groups.io
Subject: Re: [airspy] HF+ vs NetSDR Comparison

 

Hello all-

At http://sdr-radio.com/AirspyHFPlus

With regard to the NDB band comparision- when I click on the two 'thumbnails' to pull up more detailed screenshots, the HF+ screenshot is taken at 21:05:38 while the NetSDR screenshot is at 22:04:02. Signal and noise levels in the NDB band can vary quite a bit in that amount of time. Probably due to a file naming hiccup during webpage creation.

73,

Joe F. KC8RKL


Chris Smolinski
 

As a netSDR owner, I look forward to the HF+. I also have an SDR-14 and an AFE822x (plus the obigatory RTL dongle or three), so it will be interesting to compare them. I run nightly recordings of the 43m pirate band as well as the DGPS band.

If the API to use the HF+ is reasonable, I may try to add support for it to Amalgamated DGPS for real time decoding of the entire DGPS band: http://www.blackcatsystems.com/software/dgps_decoding_software_sdr.html


Chris Smolinski
Black Cat Systems
http://www.blackcatsystems.com


prog
 

Thanks Chris. The target price is < $200 and the performance should be decent. I hope you will like it.


PMM
 

I cant wait to get my hands on a HF+ bandwidth not an issue but I think in seeing comments here, I think lf a killer product was to develope it would be a mult channel dac like multiple hf+ inline with a broadband dac where programme like sdr# would have like tuning as present but dac placement also within the larger bandscope so you see your broader activity but you centre the more sensitive reciever within your area of interest... If that makes sense 😂 well it does to me lol.

On 6 Oct 2017 14:50, "prog" <info@...> wrote:
Thanks Chris. The target price is < $200 and the performance should be decent. I hope you will like it.


prog
 

I cant wait to get my hands on a HF+ bandwidth not an issue but I think in seeing comments here, I think lf a killer product was to develope it would be a mult channel dac like multiple hf+ inline with a broadband dac where programme like sdr# would have like tuning as present but dac placement also within the larger bandscope so you see your broader activity but you centre the more sensitive reciever within your area of interest... If that makes sense 😂 well it does to me lol.
I appreciate your effort. Of all the comments, this one is the closest to reality, so I will try to complement it.

The only missing information here is that the narrow band (more sensitive with higher dynamic range) receiver would require more RF filtering centered around the tuned frequency, which is not fine for the broadband receiver. This means you need two actual receivers with separate RF paths and a multiplexer - and this costs more money.

In utopialand, some direct sampling receivers with simple low pass filtering try to get the narrow band performance along with the wide band flavor using a simple DDC. This works very well in the lab with simple tones. In reality, the actual cost is poor IM3 performance with the real signals. It's never a good idea to have a lot of RF gain at a wide open bandwidth.

The higher end, more pragmatic direct sampling receivers address the problem differently. They have very carefully tweaked RF amps and extensive filtering which limits the exposure of the ADC to blockers/interference. Some radios like the NetSDR even notch specific points of the spectrum depending on where you are tuned, just to avoid potential products and/or their harmonics. This also allows them to have a relatively lower usable NF (MDS) without the fear of overloading.

Now the HF+ follows the same design principles, but the technological bricks in use are quite different (More on this later).