There is a suggestion on the web that the pilot carriers for US DTV are worth using. I tuned one earlier to day on a GPS stabilized AirSpy R1 and figure they are good for 1ppm level, at least. I am not sure what the digits beyond the XXX.310 MHz should be I saw about 400 Hz low. But that may be that the correct frequency really is slightly below XXX.310 MHz. At the very least it is more accurate than most cheap handheld equipment.

{^_^}

On 2017-11-21 12:32, prog wrote:

[Edited Message Follows]

On Tue, Nov 21, 2017 at 05:47 am, Dave C aka Dave3825us wrote:

It was 462.something. I used a cobra walkie talkie . Tried from 5 feet away
to 1 foot away. Get like 3.xx something ppm, then -1.04 ppm and after 4 or 5
tries its now at 0.06.
Do you really believe a cobra walkie talkie is a good source for stable carrier? The signal is **frequency** modulated in function of your ambient audio. ie. completely random. Plus even without modulation, these talkies have worse frequency accuracy and stability than the Airspies.
I suggest you send it to Joe at airspy.us for proper calibration.

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[Edited Message Follows]
On Tue, Nov 21, 2017 at 05:47 am, Dave C aka Dave3825us wrote:
It was 462.something. I used a cobra walkie talkie . Tried from 5 feet away
to 1 foot away. Get like 3.xx something ppm, then -1.04 ppm and after 4 or 5
tries its now at 0.06. Do you really believe a cobra walkie talkie is a good source for stable carrier? The signal is **frequency** modulated in function of your ambient audio. ie. completely random. Plus even without modulation, these talkies have worse frequency accuracy and stability than the Airspies.
I suggest you send it to Joe at airspy.us for proper calibration.

[Edited Message Follows]
Hi,
I see that in the release notes for r 11628 onward that "Set RTL max frequency to 14.4 MHz in direct sampling mode." has been added.
Is there any particular reason for this ?
I understand the desire use the tuner chip as much as possible in order to avoid Nyquist Alias signals and to have RF gain control. But I have an application where I wish to continue using direct sampling above 14.4MHz and this change has caused problems for me.
Could I suggest that it may be better if the user / admin could set this as required, as some configurations may need to use direct sampling above 14.4MHz and others may not.
It would be even better if it was possible to define frequency limits for direct / quadrature sampling in SDR Sharp and Spyserver, so that this could change automatically when the defined frequency boundary is crossed. This would save having to reconfigure things manually for example when you wish to move from HF to VHF and allow a mix of HF / VHF / UHF frequencies to be scanned.
It may also be possible to extend this proposed configuration option to automatically turn spyserver on-off (along with the frequency off-set) or turn the bias tee on / off (if folks are using this to switch antennas or pre-amps in / out).
Regards,
Martin - G8JNJ

On Nov 21, 2017, at 5:40 PM, Jeff Kelly <jkelly@...> wrote:

Hmmm - gonna try the 8 mhz for a little while!  :-)

On Nov 21, 2017, at 5:23 PM, Marcus D. Leech <mleech@...> wrote:

On 11/21/2017 05:21 PM, prog wrote:

On Tue, Nov 21, 2017 at 02:06 pm, Jeff Kelly wrote:

It does burp a little with the 8 mhz bandwidth of the airspy. so wouldn’t recommend that.

The Odroid XU4 has a slight edge on this use case.

On Nov 21, 2017, at 5:23 PM, Marcus D. Leech <mleech@...> wrote:

On 11/21/2017 05:21 PM, prog wrote:

On Tue, Nov 21, 2017 at 02:06 pm, Jeff Kelly wrote:

It does burp a little with the 8 mhz bandwidth of the airspy. so wouldn’t recommend that.

The Odroid XU4 has a slight edge on this use case.

On Tue, Nov 21, 2017 at 02:12 pm, Patrick wrote:

I simply wish the combo SDR# HF+ is so great that I won't need other soft for these purposes.

 

Best regards

Patrick

Well. Make it great then! Learn how to use the plethora of plugins available to you - starting from the Aux VFO.
But of course, as long as you are unable to see DSP flaws in software, your perception of "great" will be flawed as well.
Unfortunately, we cannot spend time on producing quality DSP and educate everybody at the same time.

On Tue, Nov 21, 2017 at 02:05 pm, Patrick wrote:

As a hardcore NDB & MW DXer, I also hope to use my HF+ with Studio 1 because of its very sharp CW filters and superior waterfall readability.

I made some tests using SDR# 1626 on the NDB band (where several beacons can be found within a few Hz) and found it quite poor. For MW carrier monitoring, I also found resolution disappointing (recorded files were used)

 

Will HF+ and SDR# allow to clearly see several carriers within 10 Hz and separate a couple of beacons within  a few Hz too ? I hope so !

 

Patrick

If you don't mind aliases (ie. signals that aren't there) you can use whatever software you wish.

On Nov 21, 2017, at 4:33 PM, weird_joe@... wrote:

Hi Everybody,

I have a few questions on the real life situation with mini computers and the Spyserver.
- I'd like to know how the CPU load of e.g. a Raspberry Pi 3 is when running the Spyserver with a device like the Airspy or Airspy Mini (more than 8 bits)?
- Do I have to reduce the FFT framerate in order to not overload the CPU? 
- What bandwidth can I practically use? Full spectrum? (full 10MHz on an Airspy?) I am really impressed how low the CPU impact on a second connected client is when running it under Windows. 
- Would you recommend a more powerful mini computer, like the Asus Tinker or Odroid octa core with twice as much RAM and much more performance?
- I believe the Asus Tinker has the exact same physical outlines of the Pi3, and there are plenty of inexpensive metal cases that should minimize the RF noise - so I guess that would be an advantage against the Odroid boards which are available with the faster memory modules than the fastest SD cards as far as I have been reading. Any recommendations on that?
- Do you have any recommendations on where to get a low RF-noise 5V 4A power supply for these more powerful boards?
- in case performance on these boards is no big issue, can I also run several Spyserver in separate directories addressing different receivers in parallel in Linux like I currently do on my Windows server?
- I have just been trying to run the Spyserver on my little Raspberry-Pi Zero W with the latest OS (slim version w/o GUI) but the only thing I get a a segmentation fault. The relatively dumb RTL-TCP server runs fine, so the dongle and driver setup works. So far I could not find out what the actual problem is. I have already been reformatting the SD card and put the latest image on.

In advance many thanks for any constructive feedback!