Problem With Set up (SDRPlay @ SDR Console

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saint
Posts: 11
Joined: Sat Oct 03, 2015 1:27 am

Problem With Set up (SDRPlay @ SDR Console

Postby saint » Wed Oct 21, 2015 9:59 pm

I just received my SDRPlay and downloaded the SDR console software, I installed the extio file and the other file. I see that I now have on my computer Visual C ++, SDRPlay EXTIO Installer Version 3.1 and also Mirics Flexi TV drivers And DLLs.

I start up SDr console and I get it running but there is something wrong, all the signals I receive are not coming in strong it's like something is interfering with the signals. All the Audio on any AM Shortwave radio stations right across the bands are very distorted and weak. This is also happening to the Ham operators that I try and listen to, if you look at the screenshot I am providing you can see all the am radio signals are very weak and this is happening to anything I try and tune in also the audio is very low and distorted like it's attenuated. I tried re-installing everything but still no luck, I have tried two different antenna's but the antenna's are not the problem.

The link will take you to the screenshot

https://www.dropbox.com/s/cvwbt2x8jn9ni ... 7.png?dl=0

Any help appreciated, I have been trying for a couple of hours but can't figure out what the problem is.
Steve
Last edited by saint on Thu Jan 01, 1970 12:00 am, edited 0 times in total.
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Tech_Support
Posts: 202
Joined: Mon Jun 01, 2015 7:00 pm

Re: Problem With Set up (SDRPlay @ SDR Console

Postby Tech_Support » Wed Oct 21, 2015 10:07 pm

Dear Steve,
The first thing to check is that your gain is not set too high. this will cause the receiver to overload and give the impression that the sensitivity is very poor.
Typically, people find that they need >50 dB of gain reduction if they have a decent antenna.
If this doesn't help, please let us know your basic settings (gain, bandwidth etc) and what type of antenna you are using.

Sincerely

SDRplay Tech_Support
Last edited by Tech_Support on Thu Jan 01, 1970 12:00 am, edited 0 times in total.
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saint
Posts: 11
Joined: Sat Oct 03, 2015 1:27 am

Re: Problem With Set up (SDRPlay @ SDR Console

Postby saint » Thu Oct 22, 2015 12:18 am

I have Windows 10/x64 on my pavilion dv7 laptop, I have SDRPlay set at 250 MHz, I click on AGC and set the gain to 50, or lower or higher it makes no difference. I click on Fast, I'm using 80 feet of speaker wire out on my balcony and also I have a discone antenna and it makes no difference on the antenna's when I try and listen to AM shortwave the audio is distorted and sound like some thing is not set right, I have the same problem with USB, AND SSB, I had the same set up with my Icom r75 radios and had no problems, I have reset the program and still no luck, I have been trying to fix this for several hours and can not think of anything else to try.
Steve
Last edited by saint on Thu Jan 01, 1970 12:00 am, edited 0 times in total.
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saint
Posts: 11
Joined: Sat Oct 03, 2015 1:27 am

Re: Problem With Set up (SDRPlay @ SDR Console

Postby saint » Thu Oct 22, 2015 12:41 am

Also as I stated in my other post can you tell me if I am supposed to have The merics tv drivers and DLLS on my computer.
Steve
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DaveB
Posts: 129
Joined: Sun Feb 01, 2015 6:04 pm

Re: Problem With Set up (SDRPlay @ SDR Console

Postby DaveB » Thu Oct 22, 2015 9:23 pm

Hi Steve,
From your screen shot it appears you have the LNA threshold at 50db, the Gain Reduction at 0db and the Visual gain at 0dB. This is WAY too much gain and will bring the noise floor so high that you can only see the tops of the strongest signals.

Typical settings from left to right of the gain controls in SDR-Console. LNA 59dB, Gain Reduction 50 dB and Visual gain -15 dB. All these numbers are actually gain reduction figures - so it may be that you have fallen into the NOT obvious trap of thinking 0 = no gain, when it is just the opposite. These are the default settings in the SDRPlay EXTIO for HDSDR and SDR#.

The LNA 'gain' is the threshold at which the front end amplifier within the Mirics chip will turn on or off. If the LNA number is higher than the Main Gain the LNA will be on and add 24dB gain to the front end. I normally run LNA threshold at 59dB and the Main gain reduction at -57db to keep the LNA on. The "Visual gain" seems to be the gain setting around the ADC and running at zero leaves no margin for overload -15dB is the default figure and quite honestly I see no degradation in the S/N ratio on a signal if I change the figur from 0 to -30 so I leave it at the default.

If you have, for example, the gain reduction set to 50dB then changing the LNA GR from 49-0 will have absolutely no effect - it's only when you get to 51dB that any benefit from the LNA will show up - as improved S/N ratio and a lower noise floor. There will be no change from 51-59 as it is purely an on/off threshold.

In SDR# as I don't have SDR-console installed just now (took it off a week ago and yet to try the newest release) if I set the SDRPlay with 59/0/0 - on a 70MHz dipole (1m each element) on the MW band I get overload and intermodulation. Set the Gain reduction to 40dB or more and everything clears up. By coincidence I was testing out an 'old' Lowe HF-225 on MW this afternoon comparing it with the SDRPlay and the SDRPlay was giving similar results on a weak signal.

The same applies on the FM Band - so I'm sure you'll find a vast improvement and probably not need to change settings that often. The FM band is a good place to experiment with settings as you have steady signals and I'm sure you can find weak signals to test out the abocve settings.

If you have a pre-amplifier then you most likely would turn the LNA gain threshold down to less than the main gain as it will make no difference to the S/N ratio. This is particularly the case above 60MHz as the SDRPlay RSP has a low noise pre-amp in front of the Mirics tuner chip which is on all the time and provides something like 18dB gain at 1.0 dB noise figure. On an un-amplifed FM aerial there is significant degradation in S/N ratio when the LNA threshold is set to below the Main gain figure. On an aerial with a pre-amp there is no difference on or off as the aerial preamp set the S/N ratio.

David
Last edited by DaveB on Thu Jan 01, 1970 12:00 am, edited 0 times in total.
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