New User Problems

Discussions about everything to do with SDRuno
g1hbe
Posts: 494
Joined: Sat Jan 17, 2015 3:28 pm
Location: Cheshire, UK

Re: New User Problems

Post by g1hbe » Tue Nov 28, 2017 7:06 pm

Hi Tom. SDRUno has a steep learning curve, but once you've mastered it it is a very powerful, feature-rich program.

I've had the original RSP1 and now I have the RSP2.

The RSP1a has only one antenna input, so you obviously haven't got THAT wrong! The only thing that springs to mind is the frequency entry. It's normally in KHz, so if you want frequencies in the MHz range you have to add three noughts. Or you can use the blue MHz button (top right on the onscreen keypad) to indicate you are entering in Mhz.
So to enter 89.3 MHz:
1. <space bar> to clear frequency
2. you can either type 89300 <enter> or
3. 89.3 <Mhz key>.

The other thing is the GAIN (or Gain reduction) setting. As an initial setting put it half way, this will do for most listening. Too much gain (GR setting right down) can cause sulking.

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Andy

GM4FDM
Posts: 11
Joined: Sat Nov 18, 2017 4:19 pm

Re: New User Problems

Post by GM4FDM » Tue Nov 28, 2017 8:19 pm

g1hbe wrote:Hi Tom. SDRUno has a steep learning curve, but once you've mastered it it is a very powerful, feature-rich program.

I've had the original RSP1 and now I have the RSP2.

The RSP1a has only one antenna input, so you obviously haven't got THAT wrong! The only thing that springs to mind is the frequency entry. It's normally in KHz, so if you want frequencies in the MHz range you have to add three noughts. Or you can use the blue MHz button (top right on the onscreen keypad) to indicate you are entering in Mhz.
So to enter 89.3 MHz:
1. <space bar> to clear frequency
2. you can either type 89300 <enter> or
3. 89.3 <Mhz key>.

The other thing is the GAIN (or Gain reduction) setting. As an initial setting put it half way, this will do for most listening. Too much gain (GR setting right down) can cause sulking.
Well I got that spectacularly wrong thanks. I didnt realise you needed the extra noughts so was actually listening on the very low frequency bands with a VHF antenna, no wonder I couldnt hear anything..... Gewtting signals now... thanks

Tom

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GM4FDM
Posts: 11
Joined: Sat Nov 18, 2017 4:19 pm

Re: New User Problems

Post by GM4FDM » Sun Dec 03, 2017 3:50 pm

Another newbie question. I have the receiver gain set as low as possible - or RF Gain Reduction at maximum..... but can I add any attenuation into the chain? I am experiencing a strange problem, and i wondered if was due to overload. I am listening airband and have a major airfield about 1 mile away. Aircraft taking off and passing my house are VERY close.

Now when am tuned to a local signal I get (what I would call weird) a problem which does not appear to manifest itself on weaker signals.

When I get a local AM signal, the audio is distorted for about half a second almost as if the receiver was drifting onto frequency.
It starts off sounding like an SSB signal then drifts on to a clean AM signal. Its hard to expalin but it does sound like the receiver RSP1A is drifting onto frequency rather than having a clean received signal. I have tried widening the bandwith to 20Khz but it really doesnt make much of a difference.

I do not seem to experience this on signals which are further away and weaker......

Any ideas??

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Tech_Support
Posts: 499
Joined: Mon Jun 01, 2015 7:00 pm

Re: New User Problems

Post by Tech_Support » Sun Dec 03, 2017 4:33 pm

Hello GM4FDM,
Do you have a frequency offset between your LO and VFO? This is very important with AM signals in Zero IF mode. The reason for this is that in a zero IF receiver, the LO appears at DC in the I/Q baseband paths and the DC offset compensation algorithms are designed to suppress DC offsets. The bandwidth of the DC offset compensation filters is a few tens of Hz and of the carrier of your AM signal is within a few tens of Hz of the LO, the DC offset compensation software will suppress the carrier of your AM signal and cause the AM demodulator to deliver a distorted output. Depending upon the angle and speed of approach, you might see up to around 50 Hz of doppler shift on VHF air band signals and this might be sufficient to pull the carrier both into and out of the bandwidth of the DC offset correction loop as the aircraft comes past you. It is unlikely that you will have overload issues with a single AM signal with your receiver set to minimum gain. We recommend ensuring that the LO is separated from your desired VFO frequency by 10 kHz or more. Alternatively, you can try Low IF mode and in this mode, there is no problem with the LO and VFO being the same frequency.

Sincerely

SDRplay Tech_Support

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Kevin
Posts: 12
Joined: Sun Mar 26, 2017 9:29 pm

Re: New User Problems

Post by Kevin » Sat Jan 13, 2018 1:11 am

Got the general idea as to why the need to shift the LO a few Khz in order to prevent audio distortion while listening to a frequency in Zero IF mode but if you select Low IF mode there seems to be no need to add that separation. Which begs the question why have a Zero IF mode selection in the first place ?

Kevin

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Paul
Posts: 355
Joined: Fri Feb 17, 2017 9:52 am
Location: SW UK

I HOPE THAT THIS MAY HELP

Post by Paul » Sat Jan 13, 2018 8:21 am

Finding one's way through the SDRUNO ser manual could be easier but SEE:

SDRuno manual

3.9 Entering frequency directly

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Kevin
Posts: 12
Joined: Sun Mar 26, 2017 9:29 pm

Re: New User Problems

Post by Kevin » Sun Jan 14, 2018 12:47 am

Hi Paul,
Understanding what is stated in 3.9 of the user manual. However this does not explain the differences in the use of Zero IF mode and Low IF mode. I don't want to input an improper setting if it's not necessary. I would like to believe if a setting is to be changed the reason behind it should be understood.

Kevin

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sdrplay
Posts: 978
Joined: Wed Jan 07, 2015 7:58 am

Re: New User Problems

Post by sdrplay » Sun Jan 14, 2018 1:01 am

Low-IF mode does not have the DC spike that is present in Zero-IF mode, however it also doesn't support large bandwidths, so if you switch between Low-IF and Zero-IF modes you will see the sample rate and DEC buttons have different values.

You cannot get a bandiwdth greater than 2MHz with Low-IF mode.

Hope that answers your question

Best regards,

SDRplay Support

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Kevin
Posts: 12
Joined: Sun Mar 26, 2017 9:29 pm

Re: New User Problems

Post by Kevin » Sun Jan 14, 2018 9:19 pm

Thanks SDRplay Support. You answered my question. Now I fully understand. Outstanding product and support.

Kevin

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