RSP1A: wobbling spurs around 2.335MHz * n

[DK7OB]

Just tried your websdr on my smart phone (since I'm at work and company firewall blocks non standard ports) and it worked fine. Heard a EA7 station on 40m SSB. Nice!

[g1hbe]

Phil.

I don't listen much above 160 m these days, but I think the upper roll-off must be pretty slow as MW and 160 both seem just as lively as ever.

[vk7jj]

Just tried your websdr on my smart phone (since I'm at work and company firewall blocks non standard ports) and it worked fine. Heard a EA7 station on 40m SSB. Nice!

Excellent.

Did a bit of fine tuning:
- increased the dynamic range of the waterfall and reset it's default level
- removed audio and FFT compression which improved the fidelity of audio and waterfall
- increased the sample rate. RF receive bandwidth is now around 6.9MHz to 7.4MHz

p.

/edit
- restored the audio and FFT compression, unfortunately the difference in internet network bandwidth of compressed to uncompressed is 200kbs v 1.3mbs

[vk7jj]

I don't listen much above 160 m these days, but I think the upper roll-off must be pretty slow as MW and 160 both seem just as lively as ever.

Hi again Andy, I must try your approach, extending the bottom rolloff downwards so as to preserve general HF operation is all I've done. Thanks for your comments and input.

Regards,

p.

[Sasan]

Well in my case RSP1A is better than RSP2.
As I've already posted here (viewtopic.php?f=7&t=2797) about my internal noise issues, I only have one such spur on RSP1A, but two on RSP2 !



RSP2 without any antenna attached on CubicSDR on a MacBook: (I've the same situation in other harmonics of these frequencies, like near the 40m band)

[Sasan]

More info about my above post:
1- I'm sure a lot of you already know: changing the IF mode, changes these frequencies;
2- In Zero-IF mode, these are my spurs on RSP2:

2.297MHZ , 2.326MHZ
4.599MHZ, 4.658MHZ
6.906MHZ, 6.993MHZ
9.187MHZ , 9.300 MHZ
and on and on. These "pairs" are only visible below 16MHZ. There are other spurs on higher frequencies but they're not "pairs"

On RSP1A with Zero-IF:
2.519MHZ , 5,030, 7.533 , etc

These numbers probably will change with time/temperature but I didn't test that.

P.S: These spurs do not interfere with my daily experience and I can safely ignore them. But investigating the root cause and being able to attenuate them in future versions would be good.

[DK7OB]

Just for laughs I show my Hammy Hambone solution for the spur in the 40m band. It's a 47 Ohms 1206 SMD resistor connected to 5V and glued to the offending chip. The ~0.5 W dissipation creates enough heat to move the spur down to 6.92 MHz.

Merry Christmas and a happy new year!

2017-12-23_14-06-20_v1.jpg (84.38 KiB) Viewed 28343 times

[vk7jj]

Just for laughs I show my Hammy Hambone solution for the spur in the 40m band. It's a 47 Ohms 1206 SMD resistor connected to 5V and glued to the offending chip. The ~0.5 W dissipation creates enough heat to move the spur down to 6.92 MHz.

Merry Christmas and a happy new year!
2017-12-23_14-06-20_v1.jpg

Good one!

Have a good holiday break, everyone.

Phil