The inventions and products featured on these pages were chosen either for their
uniqueness in the RF engineering realm, or are simply awesome (or ridiculous) enough
to warrant an appearance.
For the past few months, this full-page BridgeCom advertisement has been
running in the American Radio Relay League (ARRL) magazine QST. When
I first saw it I though it might be one of those research laboratory hydraulic
apparatuses for generating the kind of pressure found at the center of the Earth.
Scientists use such devices to
synthesize diamonds by compacting coal.
BridgeCom Systems'
BCD-144250 Duplexer for amateur and commercial applications. The BCD-144250
utilizes four high-quality cavities that results in uncompromising duplex isolation.
It will handle up to 250W continuously for the most demanding applications.
Due to the right material choice and temperature compensated design temperature
stability has been achieved.
For 144-174 MHz
Up to 250 W continuous input power
90 dB Isolation
Frequency Separation 0.6-15 MHz 19"
Rack Mountable 485 x 102 x 755 mm (19.1 x 4 x 29.75 in)
Price: $1,395.00
This is a good example of the amount of money and effort spent by private
individuals and groups in order to provide public emergency response services.
The total cost of the equipment in that rack likely tips the scale at $5,000
or more with the
repeater unit, repeater controller,
power supplies, antenna(s),
various and sundry cables, computer and software, modem and router for Internet
connectivity, and lodging space for everything. Then, there is the recurring costs
of electricity, heating, cooling, transportation, etc.
All these burdens are
happily borne by the same group of people (citizen Hams) that the Federal Communications
Commission (FCC) has decided to charge a
$35 fee
(down from the originally proposed $50) for obtaining a new license
or upgrading an existing license - even though the license testing services
are also provided by volunteers (VECs)
at their own time and expense.
As the ad states, "Ham Radio Saves Lives!" Isn't
government bureaucracy a wonderful thing?
RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling
2 MB. Its primary purpose was to provide me with ready access to commonly needed
formulas and reference material while performing my work as an RF system and circuit
design engineer. The World Wide Web (Internet) was largely an unknown entity at
the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps
while tying up your telephone line, and a lady's voice announced "You've Got Mail"
when a new message arrived...
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All trademarks, copyrights, patents, and other rights of ownership to images
and text used on the RF Cafe website are hereby acknowledged.
