They all perform well, look good, and have
saved me a lot of money. They’re not all that
difficult to build, so you can do the same. If you
are just jumping into electronics, you may want
to buy a simple inexpensive supply just to get
you started. Then, you can build your own as
needed. One word of caution here. In recent
years, linear supplies have gone out of favor due
to the more efficient switch mode type of
supply. However, when you have AC outlets
everywhere, efficiency is not a great concern.
The last thing your test bench needs is another
source of RFI, so stay with the linear supplies.
When it comes to function generators,
Waveteks from the ‘70s are my first choice.
Entering the ‘80s, Wavetek merged and changed
ownership so many times, it was hard to keep track of just
who they were. Unfortunately, the later model plastic case
equipment I have used seemed to be of lesser quality. I
have had good results with the ‘70s vintage all metal
enclosure units, though.
One of my favorites is the model 111. It is just a basic
function generator with sine, square, triangular, and
positive or negative pulse outputs — all of which can be
externally swept. The high end is only 1 MHz, but it is
made in one sweet little package occupying very little
bench space. It is
accurate and of very
high quality
construction. I also like
the model 114 which
has all the above, plus
internal sweep
capabilities as shown in
Figure 2. Actually, the
model 110 through
model 142 are all of
equal quality and
construction, with each one having their unique additional
features and upper limit frequency generation ( 10 MHz
on the 142). Expect to pay between $30 - $180,
depending on the model and condition.
Hewlett-Packard radio frequency generators (in my
opinion) are the best out there. Their early history is
steeped in leading RF products, partly by acquisition of
other high-end companies in the field. In this category, my
choice is the HP8654B shown in Figure 3. It is without a
doubt the finest L-C (inductor/capacitor tuned) generator I
have ever used or owned.
It covers 10 MHz to 520 MHz in six bands, putting
out a beautiful sine wave of up to + 13 dBm (about 2.8V P-The HP8640 is another good generator similar in
specs to the 8654, but it does tune down to 450 kHz. It
also has a built-in frequency counter and a larger footprint.
Expect to pay $250 - $600 for this one. There are add-on
units available that tune the 8,654 down to 100 kHz, and
then 8,640 up to 1,040 MHz, but are somewhat rare to
come by.
While I am on the subject of RF generators, I just have
October 2015 27
FIGURE 1. Lab built supplies.
FIGURE 2. Wavetek
Model 114.
FIGURE 3. HP8654B and HP8655A.
