I'm really interested in building the product detector and second and third
mixers for my R4C as described in the recent QEX article. My question is
(and please pardon my ignorance) in 2 places an SN 602 IC is called for but
I can find no trace of such a component anywhere. Is the SA 602 or NE 602
the same? I'm a ham but a musician by trade and learning this stuff as I go.
Thanks in advance.
Andy W1AWB

Thanks Allison!

wrote:

On Mon, 6 Mar 2006 10:44:38 -0500, "Andy Bullington"
wrote:


I'm really interested in building the product detector and second and third
mixers for my R4C as described in the recent QEX article. My question is
(and please pardon my ignorance) in 2 places an SN 602 IC is called for but
I can find no trace of such a component anywhere. Is the SA 602 or NE 602
the same? I'm a ham but a musician by trade and learning this stuff as I go.
Thanks in advance.
Andy W1AWB



Looked at the article and it's a misprint, NE/SA602 are the same
thing. The true believers will argue they are not identical but,
for R4C service they are interchangeable.


Allison

They come off the same production line, but one has been tested over a
wider temperature range. Generally the looser specced parts from any
semiconductor vendor are either untested at the tighter spec (and may
work there) or are rejects from the tighter spec testing but still pass
lower spec.

If you aren't going to operate where you are either shivering or baking
then the looser spec part will be fine.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Posting from Google? See http://cfaj.freeshell.org/google/

The NE602 was an old part. The product was bought by another company
(Signetics?) who renamed it SA602, but kept the rights to the name NE602 so
sometimes you still find an NE602. Worse yet, the NE/SA 612 is a little
more widely available and somewhat cheaper -- sometimes a lot cheaper. It
is the same part with a little different set of QC tests, so for any
imaginable application, all 4 parts are the same thing. If you were doing
some military application there might be a slight advantage to the 602 over
the 612, but even that isn't clear from the spec sheets. Usually (but not
always) if you find an NE part it will be "old stock". Sometimes the 602
will be a few cents more than a 612, other times it will be 2 or 3 times the
price, although it's only a couple buck part so paying double isn't going to
break the bank, anyway.

The NE602 was widely used in a lot of projects, and still is. Hams got used
to calling it an NE602 so the name stuck, even though an actual NE602 is
hard to find anymore and the alternatives at least as good. Guys who build
lots of receivers have a drawer marked NE602 that probably contains more
SA612's than NE602's.

...

"Andy Bullington" wrote in message
news
I'm really interested in building the product detector and second and
third mixers for my R4C as described in the recent QEX article. My
question is (and please pardon my ignorance) in 2 places an SN 602 IC is
called for but I can find no trace of such a component anywhere. Is the SA
602 or NE 602 the same? I'm a ham but a musician by trade and learning
this stuff as I go. Thanks in advance.
Andy W1AWB

xpyttl wrote:

The NE602 was an old part.

Speaking of the NE602 - the old one - I have a question...

Is my chip dead, or is 40 meters dead?

I recently got re-interested in RF and pulled out some old parts to
play with. I wired up an NE602 on a breadboard (yeah, I know), with a
torroid, some padding caps, and a varactor for tuning, and got is
oscillating on what my scope (yeah, I know) claimed was around 7 mhz.

Lots of domestic AM broadcast interference eventually tamed, but then
only shortware broadcast received at these frequencies (ie, tunes like
AM should with a direct conversion receiver) - no ham CW. I do
remember from way back when that I found the novice 40m band useless in
the evenings and would hang out on 15m then instead. Is that still
true right now?

I know the receiver isn't totally dead as I increased the capacitance,
tuned it down to what my scope claims is 80 meteres, and heard CW.
Added an old op-amp audio filter circuit from the handbook and it's
almost useable on 80m, but tuned back up to forty and nothing but
broadcast...

What kind of ballpark magintude of oscillation should I measure if I
probe the tank (well, actually pin 7) with a high impedance probe?

In article . com,
wrote:

Speaking of the NE602 - the old one - I have a question...

Is my chip dead, or is 40 meters dead?

Can't say anything about the health of your chip.

There are times when 40 meters is dead, or pretty weak. There are
other days when it's fine. Sunspot numbers have been quite low
lately. The Western States Noontime Net on 40 meters was fairly weak
today and was weak yesterday... the net controls commented that
propagation was horrible. For a couple of days before that,
propagation was excellent and signals were just booming in.

Lots of domestic AM broadcast interference eventually tamed, but then
only shortware broadcast received at these frequencies (ie, tunes like
AM should with a direct conversion receiver) - no ham CW. I do
remember from way back when that I found the novice 40m band useless in
the evenings and would hang out on 15m then instead. Is that still
true right now?

I don't ever hear much in the old 40-Novice band segment. There's
enough foreign-broadcast interference after dark these days to drive
most ham activity out of the 7100-7300 frequencies. There's usually
some CW pipping away down at the very low end of 40 almost any time I
tune around to check.

The phone segment on 40 is usually quite active during the day, if the
band conditions aren't too horrible, since most of the foreign
broadcast interference is heavily attenuated.

My impression is that 15 is as dead as a doornail after sunset these
days.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!