[time-nuts] low noise multiplication to 100 MHz

Cash Olsen radio.kd5ssj at gmail.com
Tue Jan 26 19:24:41 UTC 2016

About 10 years ago I demonstrated a Hot Air Reflow method that is simple
and needs no exotic tools and no heroic skills to solder surface mount
devices. I also supply the solder paste in a syringe with a modified
needle. The paste is Kester Easy Profile 256.

You can see my method at:

You can order paste at: http://kd5ssj.com/solderpaste/smd-soldering

BTW the cost of the solder paste has been constant for ten years but the
cost of shipping is up more than 5x, the USPS just raised the cost of
shipping a padded envelope by about 25%.

S. Cash Olsen KD5SSJ
ARRL Technical Specialist

Message: 15
Date: Tue, 26 Jan 2016 01:50:47 -0500
From: Chuck Harris <cfharris at erols.com>
To: Discussion of precise time and frequency measurement
        <time-nuts at febo.com>
Subject: Re: [time-nuts] low noise multiplication to 100 MHz
Message-ID: <56A71747.8040605 at erols.com>
Content-Type: text/plain; charset=UTF-8; format=flowed

Hi Bert,

I have noticed that if I have the right magnification,
I can do amazing things.  Even the tiny age related
tremors that naturally occur in my hands reduce with
magnification.  The brain is a marvelous  servo mechanism.

Get a good 40x-80x zoom stereo microscope meant for
dissection, the type mounted on a boom, and I would bet
you too could deal with the small surface mount parts.

When I build with SMD, I always put all of the parts on
the top side, and use solder paste.  I used to put lots
of tiny dots out with a syringe that works a lot like a
caulking gun... only smaller.  But I found that simply
drawing a thin stripe of paste across the SMD pads
on the board, and then setting the part on the paste,
works just fine.  The solder draws towards the pads, and
leaves the space between the pins clear.  Occasionally
there will be some tiny balls sitting between the pins,
but they clean up when I clean the board with alcohol
and a brush...not that they hurt anything anyway.

The chips self center while they are floating on the
molten solder.  No need to touch them with a soldering
iron, or anything else.

I use a lab grade hot plate to bring the board up to reflow
temperature.  And I am off to the races.

For disassembly, I use an IR underboard heater, and a
hot air source... about 1/8 inch diameter, and move it
around the pin area until it melts, and then lift the
part free.

To put parts on an already populated board, I pre heat
the underside of the board to about 1/2-2/3 the way to
the solder melting temperature, and use a little gentle
hot air source to head the pads the rest of the way to
molten.  No need for soldering irons.

Practice on junk boards until it becomes natural.

-Chuck Harris

Bert Kehren via time-nuts wrote:
> We have looked at the LMK devices but with my 74 years would not try to
> solder it. There are other neat parts out there but again who is able to
> solder  them.
> Bert Kehren

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