On Feb 17, 5:57�am, Leo wrote:
On 16 Feb 2007 20:53:46 -0800, "
wrote:
On Feb 16, 5:27?pm, Leo wrote:
On 16 Feb 2007 16:22:45 -0800, "
wrote:
On Feb 16, 3:10?pm, Leo wrote:
On 14 Feb 2007 22:43:58 -0800, "
wrote:
From: Leo on Wed, 14 Feb 2007 17:50:23 -0500
wrote:
On Feb 13, 7:15?pm, Leo wrote:
On 13 Feb 2007 16:43:31 -0800, wrote:
On Feb 13, 5:13?pm, Leo wrote:
On Sat, 10 Feb 2007 15:12:59 -0500, Leo wrote:
On 8 Feb 2007 18:01:57 -0800, wrote:
snip
After seeing what a BC-221 can do when properly modified, I have no
doubt that Jim could have made a pretty nifty antenna switch out of
it!

* Cranky aside,

Good place for him! *

* ...I personally think that the BC-221 "Frequency
* Meter" was over-praised. *Yes, it has a VERY stable tunable
* oscillator and the accompanying book of numbers allows one
* to "read" (heterodyne, really) out to five places, maybe six.
* But, it never "metered" anything. *Still, it was better than
* nothing back in WW2 times.

Interesting point - I've wondered myself why it was called a
'frequency meter' when it did not actually meter anything.....why not
a *'frequency standard', or a 'frequency calibrator'?

Well, considering when it was designed (probably some time
around 1940 or thereabouts), the name sounded good. There
just wasn't any sort of "meter" device around except for an
audio-range unit or so and it didn't have all that great and
accuracy. The "frequency standards" of that time all involved
stabilized crystal oscillators. Decimal or binary indicators
on front panels just weren't there, no Dekatrons, no Nixies,
no "thermometer" displays using neon bulbs. The flip-flop
was known but there wasn't much call for support circuitry
to drive it (Schmitt triggers, sharp rise-time drivers, etc.).
It was difficult to get an oscilloscope to reach 1 MHz
bandwidth through amplification; had to be direct to the
deflection plates!

I'd like to find out the setup used to make the Tables in
the little book that came with BC-221s. Obviously some
form of automation involved from the type face and format
in the book (typed in on printed blank pages). The
"electric typewriters" were in existance and were no
doubt used, plus servo motor systems to drive the tuning
dial, but how did they coordinate the precise heterodynes
to dial position and then type it on the book form pages?
Must have been some clever engineering innovation to do
that on a production basis back in the 1940s.

The early General Radio "Frequency Standards" (up to
around 1960) were just very big work-alikes to the little
BC-221 with more bells and whistles. A circa-1950
version was at Army station ADA's Receiver site and
always checking Transmitter site carrier frequencies
(reported on the TTY order-wire). A circa-1955 version
was in the Ramo-Wooldridge Calibration Lab where I
got a tiny bit of overtime to check the time-position of
one-second ticks against WWV HF ticks on week-ends.
Had to do that due to varying propagation delays from
Maryland (? old WWV site) to southern California. Had
a big set of marine wet cells to act as an uninterruptible
power supply...BIG ones in a separate room. The stable
1 MHz output of that GR standard went to a secondary
standard HP-524 Frequency Counter that was used for
routine frequency checks of other RF gear. Much,
much easier to measure frequencies on a routine basis
that way!

An acquaintence down here made a little PIC micro
version frequency counter in a tiny wood box that used
a 9 V dry cell for a power supply...with a Hitachi LCD
panel display, back-lit with an LED. I checked the
TCXO against the 60 KHz WWVB carrier for him. Now,
thinking about that, the progress in just a half century
of my experience in electronics is nothing short of
phenomenal. Back in 1950 the electronic counter was
a NEW thing and couldn't reach more than about 1 MHz.
Transistors were just a curiosity and not fully into any
production...ICs hadn't been born and the Microprocessor
was a science-fiction dream. There weren't any LCD
display panels and no LEDs to back-light them then.
"Digital" back then involved counting on fingers. Powering
a "complex" counter and display by a small 9 VDC
battery would have sent the claimant out of the room
amidst the sound of raucous laughter...claims of
operation up beyond 30 MHz would have added to the
hooting and hollering.

And today some olde-tyme hammes insist that manual
morse code is "essential" to radio communications!
I shake my head in wonderment at these ancient radio
dinosours of pursed, disapproving lips.