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<nettime> Tending, Tuning
Alan Sondheim on Sat, 27 Oct 2007 13:16:28 +0200 (CEST)


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<nettime> Tending, Tuning




Tending, Tuning


http://www.asondheim.org/tuning1.jpg
http://www.asondheim.org/tuning2.jpg
http://www.asondheim.org/tuning3.jpg
http://www.asondheim.org/tuning4.jpg

If I tune 880 kHz on a contemporary radio, it's simple; everything is in
place and linear. 880 clearly falls between 870 and 890. If the radio is
analog, a dial is turned until the station comes in. If the radio is
digital, either up and down buttons are used or the number is entered
directly. With analog, one might tune to other, fainter, pirate signals -
perhaps something on 882, for example. With inexpensive digital radios,
these signals are skipped over.

Older crystal radios and superheterodynes worked otherwise. A crystal
radio becomes a complex hit-and-miss system of digital taps and analog
dials, creating resonance when and where a desired audible signal occurs.
The taps and dials are tending, and hunting for a signal involves a
difficult but rewarding search. I present four images of an early 1920s
crystal radio with a honeycomb coil with three tap systems connected in
series to a variometer and antenna. There are two dials, one for the
condenser in the crystal radio itself, and the other for the variable
inductor of the variometer. Here is a description from the early 1920s of
the tuning process:

"Having adjusted the crystal detector to a sensitive point, the next thing
is to adjust the switches on the coil tube P (primary), the switch on the
coil tube S (secondary) and also the variable condenser C so that the ap-
paratus will be in 'resonance' with the transmitting station.

Set the primary switch N on contact point 1 and while keeping it in this
position move the other primary switch O over all of its contacts, stop-
ping a moment at each one.

Care should be taken to see that the ends of the switch arms are not al-
lowed to rest so that they will touch more than one contact point at a
time.

If no signals are heard, set the switch arm N on contact point 2 and again
move the switch arm O over all of its contents. Proceed in this manner un-
til the transmitting station is heard. This is called 'tuning' the primary
circuit.

The tuning of the secondary circuit is the next operation. Set the secon-
dary switch Z on contact point I and turn the knob of the variable conden-
ser C so that the pointer moves over the entire scale.

If no signals are heard, set the switch 2 on contact point 2 and again
turn the knob of the variable condenser so that the pointer movers over
the entire scale.

Proceed in this manner until the signals are loudest, being careful to see
that the ends of the switch arms touch only one contact point at a time.

Next slide the coil tube S (secondary) in and out of the coil tube P (pri-
mary) until the signals are made as loud as possible. This operation is
called changing the 'coupling.' When the coupling which gives the loudest
signal has been secured, it may be necessary to readjust slightly the
position of the switch arm ), the position of the movable coil tube S and
the 'setting' of the variable condenser C.

The receiving set is now in resonance with the transmitting station. It is
possible to change the position of one or more of the switch arms, the
position of the movable coil tube and the setting of the variable conden-
ser in such a manner that the set will still be in resonance with the same
transmitting station, In other words, there are different combinations of
adjustments which will tune the set so that it will respond to signals
from the same transmitting station.

The best adjustment is that which reduces the signals from undesired sta-
tions to a minimum and still permits the desired transmitting station to
be heard. This is accomplished by decreasing the coupling (drawing coil
tube S farther out of coil tube P) and again tuning with the switch arm O
and the variable condenser C. This may also weaken the signals from the
desired transmitting station but it will weaken the signals from the unde-
sired station to a greater extent, provided that the transmitting station
which it is desired to hear has a wave frequency which is not exactly the
same as that of the other stations. This feature is called 'selectivity.'"
(from Henry Smith Williams, Practical Radio, Funk & Wagnalls, 1922-24.)

The description is of a three-tapped set with a loose coupler; in the
photographs, the variometer replaces the loose coupler, and tuning is done
with a knob. Note that what is described is a delicate set of checks and
balances; to move away from an interfering station may require all of the
tuning elements to be readjusted (trust me, in practice, it usually does).
Another difference - with the honeycomb coil I'm using, sometimes the best
results occur when the contact is touch two taps simultaneously.

I think of this as tending, much as playing a non-electronic instrument
(and some electronic instruments for that matter) is a tending - much as
dance is a tending of the body, song a tending of the voice, among other
elements. A tending is most often non-linear; every adjustment resonates
with every other, affects every other. I think this is the way the world
was, and is, just as weather is the result of innumerable factors, each of
which affects the others, often in unpredictable, chaotic ways. While I've
written about this before, I haven't had the opportunity, until recently,
to actually operate a complete older crystal radio. The act of tending
seems to be, by its very nature, an act of poetics - there is art in it,
tricks to be learned, but few shortcuts. I can "feel" the inductance as
the coils are switched and turned, and turning/tuning the condenser
"feels" different again. This has to do, technically, with resonant peaks
and valleys, but the sense is otherwise, that of tending plants or a small
world with current flowing through it, gated by crystal or diode, narrowed
by the rest of it (with a crystal set, of course, there are no volume
controls or on/off switches; it runs on the energy of the signal itself).

Somewhere here, there's a phenomenology of operating in relation to tend-
ing, analog in relation to digital, caring and justice in relation to law
and order, muscle knowledge/memory to traditional "intellect," touch/taste
to perception/hearing, and tacit/external knowledges to internal thought.
But this has gone on for too long, and the direction, aegis, of such a
phenomenology might be clear enough from my other work as well.

(Note: The two images of the crystal radio interior illustrate the coil
and condensor, which has both coarse and fine tuning. I'm using bubble
wrap to hold the coil in place to avoid strain on the original solder
joints.)






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