Reading a discussion on low parts count transmitters, I came across this description, which lacked schematics and build instructions:


Are y'all forgetting the Fireball transmitter?
Battery, key, dip relay, xtal oscillator at 29.060, antenna.
I think this about as minimalist as anyone could go.


The part that is confusing me is the "dip relay" - a quick search suggests it may be shorthand for a DPDT (double pole, double throw) relay. But in the RF world there's something called "dip tuning" so I'm confused as to whether the terminology is related.

How would one use the above components to make a CW transmitter?

  • 3
    $\begingroup$ Could be a tiny reed relay in a Dual-Inline-Package. $\endgroup$
    – hotpaw2
    Mar 12, 2014 at 4:59
  • 1
    $\begingroup$ @hotpaw2 I think you should put that in your answer. That's my take on it also. $\endgroup$ Mar 12, 2014 at 11:26
  • $\begingroup$ Doing a search on digikey.com yields 59 examples of reed relays in DIP-compatible packages. So, yup :-) $\endgroup$
    – Tom Hundt
    Apr 6, 2019 at 23:20
  • $\begingroup$ WT6B seems to have been re-assigned. And, the 1994 date on the original post pre-dates widespread internet use, so a search doesn't turn up anything useful. $\endgroup$
    – Brian K1LI
    Apr 7, 2019 at 23:44
  • $\begingroup$ A search for "fireball transmitter" points to an article here n5dux.com/ham/pubs/flyingpigs/BB0501.pdf which seems relevant $\endgroup$ Apr 8, 2019 at 1:27

2 Answers 2


This design could be using the key to control a tiny relay (possibly inside a Dual Inline Package) to connect and disconnect a tiny low power oscillator from the antenna feed.


DIP = Dual Inline Package.

  • $\begingroup$ Until today, I thought DIP meant Dual Inline Pins. $\endgroup$ Apr 7, 2019 at 20:36

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