10mhz main sp span?

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geoffreyf
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Joined: Wed Oct 31, 2018 10:38 pm

10mhz main sp span?

Post by geoffreyf » Thu Nov 01, 2018 3:48 am

I have been using HackRF one and SDR Sharp (as well as sticks and dongles), so that sets my expectations. I have just gotten an SDRDuo. I am really enjoying it and that includes what I would consider a somewhat different apparent philosophy. SDRPlay is generally interesting and lays out all the possible parameters better than SDR#

What I am missing is being able to see a full 10mhz of bandwidth span on all frequencies. I like seeing what is transmitting within a broad range of bandwidth and then to even scroll back and forth. So far in SDR Play, I can only see 2mhz of span and I can't scroll around.

Is there a way to do this?
Last edited by geoffreyf on Thu Jan 01, 1970 12:00 am, edited 0 times in total.
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Tech_Support
Posts: 499
Joined: Mon Jun 01, 2015 7:00 pm

Re: 10mhz main sp span?

Post by Tech_Support » Thu Nov 01, 2018 7:12 am

Hello Geoffreyf,
You need to ensure that the RSPduo is in single tuner mode and that you have selected Zero IF mode, then you can set the SP1 bandwidth to up to 10 MHz. If you are using SDRuno as the software, please select single tuner mode on the Main panel and then in the settings for the Main Panel (SETT button), please select ZIF mode. Now you can set the SP1 bandwidth to 10 MHz by selecting an ADC sample rate of 10 MHz.

Sincerely

Tech_Support

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geoffreyf
Posts: 2
Joined: Wed Oct 31, 2018 10:38 pm

Re: 10mhz main sp span?

Post by geoffreyf » Sun Nov 04, 2018 2:54 am

Yes, I see what you are saying and that is working for me. However, there are some details I am clearer on now. I think there may be some work flow problems in the GUI. Yes, I am using SDRUno 1.2.3.

If I switch from Single to Dual, I lose the ability to set sample rate. I should think that if I switch from Dual back to single, all should be restored to the original view when Single. This is not the case. This seems like a bug. It was this which was the source of my confusion. Having bought a Duo, I naturally wanted to explore it's modes of operation.

To set Zero-IF, or even see that I can, I have to Stop the stream then go for settings. I can then hit "Play" and, as you say, I can switch sample rate and band width. It makes some sense to me that I should not be able to Set IF mode while playing, needing to first stop - BUT that option perhaps be "grayed out" to show that it is a function and not available, rather than just disappearing it, as is presently the case.

At this point, I think the issue is that the GUI may need some work so that the work flow is more evident.

All in all, I am really enjoying RSPDuo. It's interesting to compare it to HackRF with which I am more experienced.
Last edited by geoffreyf on Thu Jan 01, 1970 12:00 am, edited 0 times in total.
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Tech_Support
Posts: 499
Joined: Mon Jun 01, 2015 7:00 pm

Re: 10mhz main sp span?

Post by Tech_Support » Sun Nov 04, 2018 8:42 am

Hello Geoffreyf,
When operating in single tuner mode, you should be able to switch between ZIF (zero IF) mode and LIF (Low IF mode) on the fly, i.e. without having to first stop the stream. In dual tuner mode, each tuner operates in LIF mode only. This is because the output from each tuner feeds into just one of the two ADCs available within the hardware and ZIF mode requires dual ADCs per operating tuner. In LIF mode, the ADC sample rate has to be fixed because it is sampling an IF whose bandwidth is fixed at around 2 MHz. In ZIF mode you can only use one tuner at a time as both of the available ADCs are used for just one tuner.
The software will retain the operating state when switching from single to dual tuner modes, except where that state is incompatible with the mode.
So, why doesn't the software automatically switch to ZIF mode when changing from dual to single tuner? We, as I said, with single tuner operation, you can use ZIF or LIF and LIF does has certain advantages under certain circumstances. For example, there is no need to offset the VFO from the LO. There is no DC spur. There are few spurious mixing products at the lower end of the HF band etc. As a result, some people prefer to use LIF mode most of the time, despite the more restricted bandwidth and you can be sure that they would also consider automatic switching to ZIF mode to be bug.
If you are having to stop and start the streams before being able to change IF mode, please update to the latest version of the software (1.24.1) because as already stated, you ought be able to switch 'on the fly' without any problems.
When operating in ZIF mode, please bear in mind that you will only obtain a bit depth of 14 bits for sample rates of 6 MHz or below. This is because of the bandwidth constraints of USB 2.0. At a 10 MHz sample rate, the ADC bit depth is rounded down to 8 bits.

Sincerely

Tech_Support

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