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images

Posted: Tue Nov 17, 2015 5:16 am
by vsboost
does anybody else get images of fm broadcast stations around 340mhz and 370mhz?

Re: images

Posted: Tue Nov 17, 2015 7:42 am
by jon
Dear vsboost
The following thread discusses spurious FM images that result from the architectural use of a block converter to cover HF and frequencies from 250 - 420 MHz

viewtopic.php?f=7&t=179

If you are a Facebook user, this has also been discussed on the public Facebook group along with proposed solutions at:

https://www.facebook.com/groups/sdrplay/

We will be publishing a white paper that covers this in more detail shortly, but there are two options for dealing with this. Either add an in-line FM filter or alternatively you can tweak the frequency plan of the block converter using the Advanced settings in the ExtIO window in the case of say HDSDR. This won't remove the spurious responses, but it may allow you to move them well away from the regions of spectrum that you are interested in.

For a future version of the RSP, we are considering both improved FM filtering to reduce these spurious responses and possibly a second RF connector for HF operation. We are certainly looking for inputs from the community as to what features people consider to be most important and we will do our best to implement these if we can. At this stage, we have no specific schedule for the next version, but please keep an eye on the website for future announcements.

Best regards, Jon

Re: images

Posted: Tue Nov 17, 2015 8:24 am
by Sasan
Yes, I do have images!
I hadn't noticed it before

Re: images

Posted: Tue Nov 17, 2015 10:31 am
by vsboost
No stress Jon it doesn't worry me the slightest we have nothing here in the 300's anyway, i just wanted to make sure this was normal behaviour. I did notice if i played with the advanced settings on the extio i was able to move them around.

I think the product is just fantastic and cant think of anything at the moment that needs improvement.