EMRFD Message Archive 4289

Message Date From Subject
4289 2010-02-18 19:24:59 patt896 Suggestions to K7ZOI & other excellent providers of amateur designs
The Winter 2010 edition of QRP Quarterly, http://www.qrparci.org, has two excellent articles. Ths first is a list of most QRP Kits available today by John King, KB3WK.

The second is an article by Walt Harriman, AE6TY, in which he describes his stand-alone, antenna to DSP, Xcvr, "Making a Software Defined Radio for the QRP Enthusiast, Part 1."

He lists three lessons learned:
Third. "Always polarity protect every board's power-in.. ALWAYS."

Here is one of my own:
"Always SOCKET discrete, active components that are not SMD."
4302 2010-02-20 01:27:23 ha5rxz Re: Suggestions to K7ZOI & other excellent providers of amateur desi
"Third. "Always polarity protect every board's power-in.. ALWAYS."



Been there, done that, and I still find the smell of burning PCB distressing.

HA5RXZ
4304 2010-02-20 11:42:05 w4zcb Re: Suggestions to K7ZOI & other excellent providers of amateur desi
----- Original Message -----
4305 2010-02-20 11:44:52 w4zcb Re: Suggestions to K7ZOI & other excellent providers of amateur desi
"Third. "Always polarity protect every board's power-in.. ALWAYS."



Been there, done that, and I still find the smell of burning PCB
distressing.

HA5RXZ

Wire the big diode directly across the two power input locations. Then
the diode doesn't even have to be in the same zip code with the PCB.
Might have a PCB in the PSU get warm if you're still not careful.

W4ZCB
And I THINK you're referring to W7zoi.
4307 2010-02-20 16:01:22 patt896 Re: Suggestions to K7ZOI & other excellent providers of amateur desi
> Wire the big diode directly across the two power input locations...

I recall that SPRAT published the ultimate reverse polarity protection circuit years ago. Think I'll look it up.
4308 2010-02-20 16:33:17 patt896 Re: Suggestions to K7ZOI & other excellent providers of amateur desi
> I recall that SPRAT published the ultimate reverse polarity protection circuit years ago. Think I'll look it up.
>Found the circuit at GQRP's site at http://www.interalia.plus.com/q_tech12.htm

If only I could obatin BUZ171, RFP8P05 and RFP15P05......