[hpsdr] Analog Devices note on protecting AD

[lstoskopf at cox.net]

analog dialog Volume 49 – April 2015

Had a great time at Hamvention and enjoyed visiting at the booth and the banquet.  Just wish that Scotty had handed me my new board for the HF2 and RF1!

Had an interesting discussion with a proud Flex owner on how much superior their 16 bit AD chip with front end amplifier feedback is compared to the one we are using.  Having popped the AD in my QS1R from a few miles away lightning strike I see at least that value in having a cheaper device with some protection in front.  So I added one of the Clifton Labs exterior amps thinking that that would add protection.  Popped another AD.  Guessing that the spec sheet indicates a small diode drop PLUS VCC safety margin.  Had the preamp on and not the QS1R so the preamp possibly hit the AD with full VCC output.  Now I turn on the RX before the preamp.

Anyway, the above article is of interest.  As for the superiority of the Flex Analog device to ours????? Are 16 bits 16 bits?

 Last year at the RSGB convention I had a short chat with Peter Chadwick about his old article on the topic of "are our receivers good enough?"  I have a complete HB transceiver built with the Plessey 1600 series devices and great crystal filters using devices for which he was an application engineer.  It hasn't been on the air for 30 years.  I need to drag it out and see how it still stacks up.

N0UU