I am looking at "Practical Radio Telegraphy" dated 1928. The RCA P-8
transmitter is described with tube converter ET-3628.

This converter is a tube replacement for the "quenched and synchrnous gaps
formerly located on the power panel". it runs 1.5 kw using 2 tubes. One of
the problems mentioned is "fading or swinging signals", in which it is
stated that "such difficulties may be encountered in the case of a heavy sea
causing variation of the antenna capacity by the rolling of the vessel ..."
it is mentioned that if, on occasion, one tube burns out and there is no
replacement, the circuit may be operated as a half wave rectifier with just
one tube. Even more interesting is what to do if both tubes fail and no
spares are available: "the operator may connect his transmitter in
plain-aerial style. This is accomplished by removing all of the connections
from the three secondary terminals of the plate transformer and connecting
the antenna to one outside terminal of this transformer, and the ground to
the other. The safety gap shunted across the secondary terminals will then
function as an oscillatory spark discharger."

DO NOT TRY THIS AT HOME. I PRESUME MORE THAN ONE SAILOR TRIED CLEANING BIRD
POOP OFF THE TRANSMITTING AERIAL AND BECAME WELDED TO THE DECK WITH THIS
SYSTEM.

Using a Poulsen Tikker form of detection, this transmitter may not have
sounded that much different from those that had dc on the plates.

Colin K7FM


---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.783 / Virus Database: 529 - Release Date: 10/25/04