Unable to select Bandwidth INPUT sampling rate. Only OUTPUT rate.

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KW4CQ_Bob
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Unable to select Bandwidth INPUT sampling rate. Only OUTPUT rate.

Postby KW4CQ_Bob » Tue Sep 15, 2015 6:55 pm

Under the Bandwidth INPUT side of the Sampling Rate column I am not able to select any of the displayed sampling rates. No problem on the Output side. I can select any of those. Does anyone have a suggestion on why I cannot select the input rates and what's preventing this?
Thanks and 73, Bob KW4CQ
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wd9ewk
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Re: Unable to select Bandwidth INPUT sampling rate. Only OUTPUT rate.

Postby wd9ewk » Tue Sep 15, 2015 11:43 pm

KW4CQ_Bob wrote:Under the Bandwidth INPUT side of the Sampling Rate column I am not able to select any of the displayed sampling rates. No problem on the Output side. I can select any of those. Does anyone have a suggestion on why I cannot select the input rates and what's preventing this?
Thanks and 73, Bob KW4CQ


If you are using HDSDR, this is because the input bandwidth is handled by the ExtIO Controller - not in the Bandwidth menu you would normally go when using other SDR devices. If you click on ExtIO to the right of the TUNE frequency, you'll see a controller pop-up like this:

HDSDR-SDRplay-ExtIO_controller.jpg
HDSDR-SDRplay-ExtIO_controller.jpg (110.49 KiB) Viewed 2410 times


The "IF Bandwidth" would be the equivalent of the Input Bandwidth setting in HDSDR.

I have been posting my observations and findings in using my SDRplay to work amateur satellites at:

https://forums.qrz.com/index.php?threads/sdrplay-as-satellite-downlink-receiver.490793/

There might be some bits in that thread you'll find useful, too.

Good luck, and 73!
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F1BJB
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Re: Unable to select Bandwidth INPUT sampling rate. Only OUTPUT rate.

Postby F1BJB » Fri Sep 18, 2015 7:12 pm

wd9ewk wrote:I have been posting my observations and findings in using my SDRplay to work amateur satellites at:
https://forums.qrz.com/index.php?threads/sdrplay-as-satellite-downlink-receiver.490793/

Nice topic.
I agree that Wide band IQ recordings is the main advantage of SDR's.
It allows careful studies of rare events like propagation or interference .
Even high grade spectrum analysers are often less efficient than RTLSDR's on that ground.
The only problem is that using *.WAV files limit size to 2Go and only a few minutes at high sampling rates.
I hope a decent solution will emerge as we are actually lucky that *.WAV files allow for such high sampling rates.
The next step is replaying those files right on the frequency they were recorded and testing various
receivers in such conditions.
For example an ILS or VOR receiver without having to fly a plane or block a runway for the purpose.
Sharing the files on the net could allow any one to share the feeling of an EME contest with a very big dish.
Nice way to learn CW too.I found myself trying to identify NDB's that way :D
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wd9ewk
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Re: Unable to select Bandwidth INPUT sampling rate. Only OUTPUT rate.

Postby wd9ewk » Fri Sep 18, 2015 10:38 pm

F1BJB wrote:Nice topic.


Thanks!

F1BJB wrote:I agree that Wide band IQ recordings is the main advantage of SDR's.
It allows careful studies of rare events like propagation or interference .
Even high grade spectrum analysers are often less efficient than RTLSDR's on that ground.
The only problem is that using *.WAV files limit size to 2Go and only a few minutes at high sampling rates.
I hope a decent solution will emerge as we are actually lucky that *.WAV files allow for such high sampling rates.
The next step is replaying those files right on the frequency they were recorded and testing various
receivers in such conditions.
For example an ILS or VOR receiver without having to fly a plane or block a runway for the purpose.
Sharing the files on the net could allow any one to share the feeling of an EME contest with a very big dish.
Nice way to learn CW too.I found myself trying to identify NDB's that way :D


For satellite work, I'm able to see and hear what else I missed on the transponder during a particular pass. With the traces in the waterfall showing different colors based on signal strength, it is easy to identify who is using more power than is necessary through a linear transponder. For the FM satellite SO-50, the SDR receiver does a better job of tracking the downlink via AFC that any AFC function I've used on receivers in the past. And the fact I can run software like HDSDR with an SDRplay on a small Windows tablet is a very good thing!

You can change the size of the WAV files written by HDSDR, but the default value makes it compatible with computers using FAT/FAT32 or NTFS filesystems. If you know you aren't writing the WAV files to a drive formatted in FAT or FAT32 (i.e., only to drives & memory cards formatted in NTFS or exFAT), you could increase the maximum size of the WAV files written by HDSDR. The danger would then be that the files would be too large to move off the computer, or would fill up all available space on the computer if the recordings go unchecked.

Good luck!
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Patrick WD9EWK/VA7EWK
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F1BJB
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Re: Unable to select Bandwidth INPUT sampling rate. Only OUTPUT rate.

Postby F1BJB » Sat Sep 19, 2015 8:52 am

No it is the header of *.WAV files that limits the size to 2 Gb not the file system of the hard drive.
There is another problem with files recorded by sound cards.
The accuracy of the sampling rate.
If you make a 24H recording at 8 Khz jumping at the end of it can result in errors of +/- 10 minutes.
I discovered that the hard way :-)
I think files recorded from SDRplay are much more précise on that ground.
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wd9ewk
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Re: Unable to select Bandwidth INPUT sampling rate. Only OUTPUT rate.

Postby wd9ewk » Sat Sep 19, 2015 2:44 pm

F1BJB wrote:No it is the header of *.WAV files that limits the size to 2 Gb not the file system of the hard drive.


I saw several sources online cite the WAV file size limit is 4 GB. In any event, HDSDR will write a new WAV file once it reaches the size limit specified in that pop-up window.

Regardless of file size limits, these WAV RF recordings are very useful. For my satellite work, they are great for reviewing what happened, away from where I was working. I have also used a WAV RF recording and screenshots from HDSDR to illustrate the moment the AO-73 (FUNcube-1) transponder shuts off, and its telemetry beacon increases its transmitter power, when the satellite passes into sunlight in its normal operating configuration.
Last edited by wd9ewk on Thu Jan 01, 1970 12:00 am, edited 0 times in total.
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Patrick WD9EWK/VA7EWK
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