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January 1969 Electronics World
Table of Contents
Wax nostalgic about and learn from the history of early electronics. See articles
from
Electronics World, published May 1959
- December 1971. All copyrights hereby acknowledged.
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 Where else on the Internet other than RF
Cafe can you go for a daily helping of electronics-related material that ranges
from the very beginnings of our chosen vocation through to the latest leading edge
developments? That Q is rhetorical of course - and self-serving to boot ;-)
This handy-dandy trick for enhancing the signal on your AM radio appeared in a 1969
issue of Electronics World magazine. I remember doing this magnet "tuning"
technique on my small, el cheapo pocket transistor radio that I carried with me
when wiring houses and buildings while working as an electrician many moons ago
after high school. It often made the difference between being able to listen to
my preferred Top 40 AM station (combo top and music at the time) in Annapolis,
Maryland - WNAV - and having to
settle for Public Radio concerts. The "NAV" part of WNAV probably derives from "naval"
both due to the U.S. Naval Academy being there and the fact that the entire Annapolis
area is very water-centric, being located on the Chesapeake Bay and multiple surrounding
tributaries. I do not miss the long, hot, extremely humid summers of boyhood. BTW,
since I still listen to AM radio part of the day, I grabbed a magnet and ran it
along the area where the internal AM ferrite rod antenna is located in my 1970s
vintage Magnavox Model 789 AM / FM / Shortwave radio (it was Melanie's
when she was a teenager) and sure enough, I was able to locate a peak in reception.
Incredibly, I am able to use it daily to listen to
WJR out of Detroit, which is
150 miles away in a straight line across Lake Erie. Here's an
article showing how to
repair a broken ferrite rod.
More Sensitivity From Your Transistor Radio
By John E. Campbell
Have you ever wished that you could squeeze just a little bit more sensitivity
from your transistorized AM broadcast receiver, especially on a single station?
If so, a gentle wave of a magic wand may make your wish come true.
All you will need is a permanent magnet and your receiver. If the magnet has
a fairly strong field you won't even need to open the case of your set. Just tune
in the station you wish to "perk up" and make a slow pass with the magnet down the
length of the built-in ferrite antenna rod. If you detect a rather sharp increase
in volume anywhere along the line, slow down and find the peak. That's all there
is to it. You can now either balance the magnet where it is, tape it in place, or
obtain some small ceramic magnets and tie or glue them in position directly on the
ferrite rod.
Suitable magnets are available from Radio Shack, Edmund Scientific Co., and many
others, A more universal supplier may be your local hardware dealer who handles
magnetic cabinet latches. Just about any magnet will do as long as the field is
strong enough to saturate a small portion of the ferrite rod.
Posted August 30, 2023
(updated from original post on 6/23/2017)
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