Re: Perseus tuning problem.


D R
 

Ready and willing, Master!

Dave


On Tuesday, 23 April 2019, 22:05:09 GMT+1, Simon Brown <simon@...> wrote:


Hi Dave,

 

Just a calibration issue. Tomorrow I’ll explain how you can help with this.

 

Simon Brown, G4ELI
www.sdr-radio.com

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of D R via Groups.Io
Sent: 23 April 2019 20:25
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] Perseus tuning problem.

 

Hi Simon,

 

Thanks for trying with the 48kHz filter.  I've had a look in the Perseus folders on my computer, and I see that in v4 of his software, Nico didn't implement 48k, 95k, 96k and 192k either, despite the files being in the installation package, and they've all been pruned from the v5 installation.  Maybe he had problems with them in the past as well?

 

It would be nice if you can eventually get 192k working, though, as it's the bandwidth I tend to use the most for NDB hunting, and it will let me have the Perseus screen looking the same as the HF+ and FDM-S2 screens.

 

Best regards,

Dave

 

 

 

On Tuesday, 23 April 2019, 16:41:10 GMT+1, Simon Brown <simon@...> wrote:

 

 

Also,

 

I can’t get the 48kHz rate working with a 64-bit application, sorry.

 

Simon Brown, G4ELI
www.sdr-radio.com

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown
Sent: 23 April 2019 16:17
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] Perseus tuning problem.

 

Dave,

 

Just ran some tests with my Perseus. The sample rate at 192kHz is actually 192.300 kHz and at 1 MHz it’s 0.999932 MHz.

 

  • At 192kHz it’s ~ 1560 ppm
  • At 1 MHz it’s ~ 70 ppm

 

This explains what you are experiencing. I will add a note to the website and, when I have time, I will run longer tests at all sample rates to calibrate Nico’s filters.

 

So, at 192kHz the error is

 

Simon Brown, G4ELI
www.sdr-radio.com

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of D R via Groups.Io
Sent: 22 April 2019 22:25
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] Perseus tuning problem.

 

Hi Simon,

 

Five screenshots attached, showing a 10MHz sine wave fed into the Perseus at 192kHz bandwidth: 01 is the signal centred in the spectrum / waterfall, and 02 and 03 show it just after it has been moved about 90kHz to either side - both show the tuned frequency unchanged at 10MHz, but the signal has clearly moved off-centre in the IF Display (proportionate to the amount the waterfall is shifted).

 

Pics 04 and 05 show the 10MHz signal at either side of the waterfall after it has been re-centred in the IF Display, showing a total frequency shift of almost 300Hz from one side to the other.

 

This error occurs at all frquencies when using 192kHz, 96kHz and 95kHz bandwidths, but the tuned frequency is locked solidly in the middle of the IF Display (as it should be) when all other available bandwidths are used.

 

I hope these pics help, but the problem is simple to verify anyway.

 

Regards,

Dave

 

 

On Monday, 22 April 2019, 15:06:57 GMT+1, Simon Brown <simon@...> wrote:

 

 

Dave,

 

Post a screenshot – this helps me immediately see what the problem is, and also whether it’s a user misunderstanding.

 

I think 48kHz doesn’t work well – not sure, but I removed it for a good reason 😊 .

 

As for the dropdowns – I’ll change the HF+, thanks for noticing this.

 

Simon Brown, G4ELI
www.sdr-radio.com

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of D R via Groups.Io
Sent: 22 April 2019 13:24
To: SDR-Radio <sdr-radio@groups.io>
Subject: [SDR-Radio] Perseus tuning problem.

 

Hi Simon,

 

There appears to be a tuning problem with certain bandwidths on the Perseus, whereby the tuned frequency changes as the waterfall is moved from side to side, either by right-clicking or by using the slider, although the frequency display still shows the original value.  It's easily audible on a CW signal, and you can also see the signal moving within the filter in the IF display.  This happens when using bandwidths of 196kHz, 96 kHz and 95kHz - at other bandwidths the selected frequency stays locked on as per normal.

 

I've noticed that there is also a 48kHz .sbs file in the program directory, but there is no 48kHz option in the bandwidth drop-down list.  As there is little need for both 95 and 96kHz widths, is there a chance of replacing the 95kHz bandwidth with 48kHz (which is really useful for DGPS band recording)?

 

One last small point: the bandwidth drop-down lists for most receivers has the narrowest at the top, except for the HF+, which has the widest at the top.  It's no big deal, but worthy of a change for consistency?

 

Regards,

Dave

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