EEVblog Electronics Community Forum
Electronics => RF, Microwave, Ham Radio => Topic started by: AG6AV on June 06, 2016, 04:53:59 am
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Hello,
I bought a SDRPlay. It is a Software Defined Radio (SDR). I am using the SDRPlay with HDSDR software. I noticed that the receiver seems to receive many erroneous tones.
The SDRPlay is a wide band receiver. Therefore, my first thought was that the receiver may be overloaded. So, I connected the SDR to a Mini-Circuits SMA 50 ohm load. This helped. Then I added some ferrite to the USB cable. This helped a little.
I would expect a receiver connected to a high quality dummy load to receive nothing. For example, my HP 8560E reports no tones when terminated into 50 ohms. However, the SDRPlay reports many tones.
Has anyone else made this observation? Anyone have a solution?
Nathan
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(http://helifor.eu/hrs/download/file.php?id=162)
You may start with Al box... keep SMA ground like only
contact to box and keep your SW gain low and/or attenuators on high.
Unit performs great on HF plus 50 & 70 MHz and delay may be useful to hear
important parts of QSO twice...
(http://helifor.eu/hrs/download/file.php?id=163)
GL 73
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I have an SDRplay. It works pretty well, but has regularly spaced birdies from DC to daylight. They are very apparent when the gain is set to -45dB or higher, if I remember correctly. I assumed they were from nearby strong overload but never got to the bottom of it. But was able to receive plenty at -50dB or so and they didn't bother me too much.
Anyway, I just got my first proper HF rig, and it doesn't have this issue, but I think it's easier to filter for the Ham bands than it is for a wideband device like the SDRplay which had to cover a lot of range with only a few prefilters.
You should get on the SDRplay group on Facebook and ask there. People will help, and I believe the designer hangs out there and chimes in.
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Yeah,
I been doing more research. Many people are observing better performance with shielding. Apparently, the RF front end is not shielded enough, and the USB port is not decoupled enough. I am not sure what the people at SDRPlay were thinking when they utilized plastic shielding. I think its a shame that SDRPlay put a lot of effort into a product, but ruined it by cutting corners. Also, be warned of the many favorable reviews of this product. All the reviews I read did not mention the serious erroneous tones produced. In other words, this receiver is so good that it receives signals that don't exist. Therefore, I put this device in the toy category.