GDE Error: Error retrieving file - if necessary turn off error checking (521:)
You can see also the conference here..
I made this LNA at home using minimal materials and money (MMIC chip and SMA connectors were bought on eBay for few dollars). It uses era-3sm+ MMIC which has 17-23 dB gain and NF of 2.6-2.8 dB. I am fairly sure it should not be called low noise amplifier because of that noise figure but it’s OK for me, I couldn’t really find a better MMIC. I was inspired to make this LNA by lna4all and lna4hf so the board is somewhat similar. If you are not into making PCBs and want to buy one you should definitely choose lna4all or lna4hf. http://lna4all.blogspot.com/ http://lna4hf.blogspot.com/
I used this site to calculate values. Lower limit is defined by coupling capacitors and is 4 MHz because I was choosing from the components I have. 4 MHz is enough for me because I am also currently making an upconverter for rtlsdr and it will have the same MMIC on board but with lower limit of few kHz.
Board layout. I assume that RF design gurus are bleeding from their eyes right now but that is what I came up with, I have only designed few boards in my life, let alone RF boards. (If you can suggest any improvements feel free to comment).
Printed with laser printer on glossy paper. The board is 2.5×2.5cm.
Transferred top side. I masked all imperfections with CD marker.
I use sodium persulfate to etch.
I find it better than ferric chloride because it stays transparent and does not leave permanent stains on everything it touches.
Vias are ugly now but the paint will hide it.
Painted with glass paint and baked.
Cleared all pads using scalpel.
Finished board. Soldering was done by hand with regular iron so it is not ideal but I am satisfied.
FM station without LNA and with 0 dB gain in SDR#.
//~~lo0king for the waves~~//