What does BFO mean on an ADF receiver?
Bernie Worral
Worr, out
kernowzx2
Frequency
Oscillator
Used for resolving the sidetone on CW (Morse) and SSB (Single Side Band /
Voice) transmissions... Ham use mostly, can't really think why it would be
used on an ADF receiver nowadays... But ya never no!
Hope this helps!
Steve Beare (G1MQU)
"Bernie Worral" <bwo...@cableone.net> wrote in message
news:u3d2uv5...@corp.supernews.com...
HECTOP
oscillator" and what it does is to generate an audio tone to let you
identify beacons that identify themselves using interrupted-carrier keying.
This feature is is seldom used in the United States except for a few marine
beacons, but can be very useful when flying in other parts of the world."
FMI: http://www.avweb.com/articles/adf.html
--
HECTOP
PP-ASEL-IA
http://www.maxho.com
maxho_at_maxho.com
"Bernie Worral" <bwo...@cableone.net> wrote in message
news:u3d2uv5...@corp.supernews.com...
Larry Fransson
<bwo...@cableone.net> wrote:
> My CFI didn't know. Neither did I.
The supplement section of the airplane's POH might help you out the next
time you have a similar question. Your CFI *should* know that.
--
Larry Fransson
Seattle, WA
Bernie Worral
Worr, out
"HECTOP" <ma...@remove.maxho.com> wrote in message
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les_I...@waitforit.com
Beat Frequency Oscillation.
We can have a democratic society or we can have the concentration of great wealth in the hands of the few. We can't have both.
-Supreme Court Justice Louis Brandeis
Richard L. Watson
It is usually found in aircraft requiring a crew of two or
more. Since the Captain is usually busy reading his
newspaper he has little time to correct the First Officer,
so he just turns on the BFO, Beat First Officer function of
the ADF.
--
Richard
TEXAS is not just a place, TEXAS is a state of mind.
<les_I...@waitforit.com> wrote in message
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S. Ramirez
"Richard L. Watson" <rwatson(no_spam)@centurytel.net> wrote in message
news:G5GZ7.11464$Xs4.2...@feed.centurytel.net...
> Nonsense.
>
> It is usually found in aircraft requiring a crew of two or
> more. Since the Captain is usually busy reading his
> newspaper he has little time to correct the First Officer,
> so he just turns on the BFO, Beat First Officer function of
> the ADF.
>
Richard,
I thought it stood for Big F*ck*ng Oscillator! When I was involved in
aviation maintenance back in the late 60s and early 70s, that's what we
called the BFO. Of course, back then we were dealing with tubes (empty
state logic).
Simon
Jim Weir
shared these priceless pearls of wisdom:
->My CFI didn't know. Neither did I.
Get another CFI.
The Beat Frequency Oscillator is a tiny little transmitter in your ADF that is
tuned very close to the station that you want to receive (*). It puts a "beat",
or audio note as a function of the difference between the BFO frequency and the
frequency being received. A squeal if you will. If the station being received
is at 380 kHz. and the BFO is tuned to 381 kHz. you will hear a 1 kHz. note, the
difference between 380 and 381.
Even if the beacon you want to hear is modulated, there is a phenomenon called
carrier enhancement that lets you hear the beat note from the BFO far before you
will hear any modulation on the beacon. You can hear that squeal when the
station is so far down into the noise that you can just barely detect that there
is "something" there.
Jim
(*) Yes, I know the BFO is beating with the IF and not the signal itself, but
that just confuses the issue for a simple discussion.
Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com j...@rst-engr.com
Darrell
switches to manually rotate the ADF sensor rather that the automatic
rotating/pointing gained by using the ADF position rather than Loop. I used to
teach this RDF procedure in Air Force pilot training in T-33s. I've seen it where
thunderstorms were in the approach area and the old ADFs would point to each
lightning bolt being produced. It made ADF unusable for an approach. Turn on the
BFO switch, go to Loop, rotate the loop L/R switch until you reached an "aural
null", a point where the two halves of the loop antenna received equal signals which
cancelled out the BFO tone. As you moved the L/R switch, the ADF pointer arrow
moved to show you where that null was. You had to solve the 180? ambiquity because
the loop has two positions 180? apart that produce the aural null. You had to make
sure you were dealing with the null that would take you TO the NDB rather than AWAY.
It was really quite a chore and everyone HATED to do RDF approaches. One hand on
the throttle, one hand on the stick, one hand on the loop L/R switch to stay with
the aural null. Whoops! One hand short aren't we? Plus it took a lot of attention
which degraded your normal flight instrument scan.
Jim Weir wrote:
--
Darrell R. Schmidt
B-58 Hustler History: http://members.home.net/dschmidt1/
Email not correct due to SPAM.