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Old 8-Sep-2020, 1:17 AM   #32
rabbit73
Retired A/V Tech
 
Join Date: Aug 2012
Location: S.E. VA
Posts: 2,747
Quote:
Originally Posted by verder
Here are a few screen caps: https://imgur.com/a/mIFfUUQ

Gain @ 8 -- no ghost
Gain @ 9 -- ghost signal appears to the right of an FM signal
Gain @ 9, shifted center frequency -- ghost slides along with the shifting.
Thank you for the images and the detailed explanation.







Quote:
On SpectrumSpy it appears as a ghost signal that appears spaced at 8MHz intervals.

I assume Airspy support is out of the office today due to the holiday. Hopefully I hear back from them this week. I guess the device has a one year warranty so I may not be totally hosed:

Airspy Warranty
Airspy warranty is limited to 1 year from the date of delivery for purchased units that fail under normal operating conditions. Airspy units will be repaired at a price of $50.00 plus $10.00 shipping/handling. Normal operating conditions do not include excessive mechanical stresses due to mishandling, dropping, or bending; mechanical or electrical modifications; Electro-Static Discharge (ESD); excessive RF signals; excessive thermal stresses due to improper ventilation or cooling, submersion in any fluid; and any unauthorized repairs.
All warranty claims will be determined by Airspy or their representatives.
It appears to be an artifact that only shows at certain gain settings. When an SDR is designed, there are many stages. The goal of the design is to balance the gain of each stage so that they all stay within their normal operating range at all gain settings.

That is why it is so difficult to have an SDR dB scale with absolute instead of relative values. The only SDR that has an absolute dB calibration that I know of is the SDRplay, and that is only under certain conditions.
https://www.youtube.com/watch?v=MRR-x_TjOp4

This my test of the SDRplay calibration:



I wasn't able to duplicate the artifact problem:

https://www.dropbox.com/s/mj126w9mt2...37-37.mp4?dl=0

https://www.dropbox.com/s/mj126w9mt2...37-37.mp4?dl=1

I notice that you have added the SNR meter plugin from GitHub. Did you have the artifact problem before you added the plugin?

Disregarding the curious ghost, does your R2 otherwise function properly?

Your R2 might be defective, or it could simply be a firmware issue.

We are both using the same software version, but since I bought my R2 first, the firmware version might be different. Airspy support would know what firmware version you have if they know what R2 you have.

There is a way for me to find out what firmware version I have, but I don't want to use a command prompt on my R2. Since my R2 seems to be working OK, I might mess it up.
AIRSPY R2 & MINI Software Defined Radio Firmware Update Procedure
https://www.youtube.com/watch?v=cMm7vC4gklA

Google search:
airspy R2 firmware

My Airspy R2 just bricked, no idea why...any suggestions for bringing it back?
https://www.reddit.com/r/RTLSDR/comm...o_idea_whyany/
click on VIEW ENTIRE DISCUSSION for this:
Quote:
melvin2204
RTL-SDR v3, Airspy Mini, R2, HF+ Discovery0 points ·
11 months ago
· edited 11 months ago

It's called 'The Ultimate VHF/UHF RX “Brick”' for a reason. Jokes aside, you might have more luck contacting @lambdaprog on Twitter. He partially runs Airspy.

level 2
byf_43
1 point ·
11 months ago

Haha, yeah I wasn't aware of that less than stellar reputation. I did get an initial email back from Airspy's customer service, but I have a feeling I won't have this up and running by tomorrow.

Do you have any suggestions for another SDR that might be more robust than the Airspy?
Quote:
Originally Posted by verder
Adapter

Also -- I'm using a SMA <--> F adapter cable. So, no "hard" connection from the Airspy to the coax going on.
Good
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Last edited by rabbit73; 8-Sep-2020 at 5:57 PM.
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