Good morning Syed and Seasalt,
Thank you for replying to my post. This morning I did some more testing on my setup and took a bunch of screen shots.
First, I performed the test you suggested. Using the Airspy, I decided to see what sort of NF jump I got when hooking up the amp. So there are two screen shots below:
- Airspy RX with just the patch antenna connected:
Airspy with patch antenna but without lna
Noise floor seems to be about -95 dB.
- Airspy RX with the amp/filter and patch antenna connected.
Airspy with patch antenna and lna
Noise floor seems to be about -80 to -75 dB, which seems shy of the 30 dB difference that should be seen.
I decided to perform the same tests using the ORx USB receiver:
- ORx receiver with patch antenna but without the lna.
ORx USB receiver with patch antenna, but no lna.
NF appears to be about -55 dB.
- ORx receiver with patch antenna and with the lna.
ORx with patch antenna and LNA
NF appears to be about -28 dB. This is pretty close to the 30 dB difference that would indicate that the LNA is functioning.
Based on the Airspy tests, I’d say that I’ve got a problem with the lna. But, based on the testing with the ORx receiver, it seems that the amp is working fine. It is interesting to me the amount of noise floor difference between the ORx receiver and the Airspy. The Airspy is a $200 device while the ORx stick is a $25 device, so perhaps that isn’t surprising or unexpected.
As a comparison test, I got out another E4000 dongle to see where its NF was. It seems to be about -60 dB, very comparable to the ORx device. As another test, I got out an R820T2 device from NooElec. The NF there also seems to be about -60 dB.
Now to see what the ORx can see outside in my backyard:
- With the ORx and lna attached to the patch antenna.
ORx pointed at satellite with lna and patch antenna.
It’s tough to see if there is any reception or not. There might be a little bit in the waterfall, it’s hard to tell. I could see this not resulting in a lock or any downloads.
- Now to swap to the airspy, with the lna and the patch antenna:
Airspy with lna and patch antenna.
Certainly, the Airspy / lna configuration is seeing the satellite. This version of SDRSharp works with the E4000, but doesn’t have the SNR calculator feature. Just to see what it is, I swapped over to a newer version that only seems to work with the Airspy but does have the calculation feature:
- Airspy with the SNR feature turned on.
Base on all the above, I’m not really certain where my problem is. Any advice would be greatly appreciated. My immediate thought would be to buy another ORx stick and LNA and see if that fixes the problem.