Hi;

I've recently bought two aircraft rx modules, there's only 'LOC/VOR
receiver' written on the chassis, neither manufacturer nor any additional
infos. Single aerial input, and several connectors. As I inspected, it is a
complete 108-117MHz rx, with RF amp, LO, mixers, quartz filters, and
demodulator. One of them (1990) is equipped with a PLL synthesis, and the
other (1975) has 10 switched crystals instead. Whole RX is a metal, rigid
can (as for high-end devices used in aircrafts). Unfortunately, I haven't
found any documentation concerned with it. The schematic diagram would be
the best, however I suppose this stuff is not widely available.
Nevertheless, if anyone had any info how to connect such things or make them
work, would be appreciated. Of course, I can redraw the wiring; although
that could take weeks

Cheers,
--
Pawe³ Stobiñski SQ9NRY @ JO90WP
Republic of Poland

In article , "Pawe³ Stobiñski"
writes:

I've recently bought two aircraft rx modules, there's only 'LOC/VOR
receiver' written on the chassis, neither manufacturer nor any additional
infos. Single aerial input, and several connectors. As I inspected, it is a
complete 108-117MHz rx, with RF amp, LO, mixers, quartz filters, and
demodulator. One of them (1990) is equipped with a PLL synthesis, and the
other (1975) has 10 switched crystals instead. Whole RX is a metal, rigid
can (as for high-end devices used in aircrafts). Unfortunately, I haven't
found any documentation concerned with it. The schematic diagram would be
the best, however I suppose this stuff is not widely available.

If you can give us some sizes (mm or cm okay) and describe the other
(not coaxial) connectors pin count or connector identification, it would
be a start. If this was used on air-transport aircraft, the box sizes,
connectors, and connector pin functions are all standardized under
ARINC specifications. ARINC documents are available from them but
are very expensive to order from that industry group. The cabinet/box
sizes are described by "ATR-x" and slide into aircraft racks (also
standardized) and lock down through bottom front end pins.

Nevertheless, if anyone had any info how to connect such things or make them
work, would be appreciated.

VOR (Very high frequency Omnidirectional radio Range) uses a
combination of AM at 30 Hz (from the ground station antenna pattern
actually rotating at that rate) and a 30 Hz signal derived from FM
demodulating a 9.96 KHz subcarrier as the reference phase for azimuth
bearing to the ground station. There are many ways to show or compare
the two 30 Hz phases (automatic or semi-manual) and would be done in
a pilot's OBS or Omni Bearing Selector, usually a separate panel
mounting instrument. The "open space" from 30 Hz to near 10 KHz can
be used for voice audio from the air traffic controller to the aircraft or
for
automated airport condition recordings.

LOC or Localizer is also a sort-of azimuth bearing radionavigation
system but is specifically for the approach path azimuth for landing.
Uses only two tones and compares the amplitudes (equal when
centered on approach path). In most OBSs, the "left-right" needle
is switchable to either VOR or LOC but the audio signals for each
function are different.

From the basic VOR function, the receivers would have a 10 KHz
minimum bandwidth and tune 108.20 MHz upwards in 200 KHz
increments. LOC tunes from 108.10 MHz upwards in odd increments,
interleaved with VOR. Note: Later ICAO (International Civil Aviation
Organization) specifications may have 50 KHz increments in some
countries, but the even-odd interleaving still holds. AM demodulation
for both receivers.

If your receivers are modules that fit into a larger one, the
full documentation would have to come from the manufacturer.
Nothing secret about it...just isn't widely used outside of the
civil aviation world.

ARINC was first organized before World War 2 in the USA as a
private airline communication company ("Aeronautical Radio, INC")
but became a non-profit industry standards group after the war,
principally for airlines and air transport companies to allow very
quick substitution of standard communications and radionavigation
radios and indicators anywhere in the world.

Of course, I can redraw the wiring; although
that could take weeks

If you can't identify the receivers from existing website manufacturer's
photographs, that might be the unfortunate necessity. Try a search
on the Internet using "aircraft radionavigation radio" and see if anything
comes close.

Personal story: In 1947 at age 14 I got started in "real radio hardware"
by having to generate a schematic for the ARC-5 airborne radios sold
as military surplus...the new store owned by two long-time hams did
not have a reproducible schematic for less than a few dollars. Took
me a week-plus to do it as a beginner using an ordinary multimeter.
By then the store had obtained copies of the schematics, selling them
for much less than originally...:-) It was good training for me at the
time. In 1981 another engineer and myself had to generate several
schematics from existing PCB assemblies because a project manager
refused to spend extra project money for documentation. Together,
we cost the project a LOT more than the documentation and wasted a
whole month. :-)

Len Anderson
retired (from regular hours) electronic engineer person

In article , "Pawe³ Stobiñski"
writes:

I've recently bought two aircraft rx modules, there's only 'LOC/VOR
receiver' written on the chassis, neither manufacturer nor any additional
infos. Single aerial input, and several connectors. As I inspected, it is a
complete 108-117MHz rx, with RF amp, LO, mixers, quartz filters, and
demodulator. One of them (1990) is equipped with a PLL synthesis, and the
other (1975) has 10 switched crystals instead. Whole RX is a metal, rigid
can (as for high-end devices used in aircrafts). Unfortunately, I haven't
found any documentation concerned with it. The schematic diagram would be
the best, however I suppose this stuff is not widely available.

If you can give us some sizes (mm or cm okay) and describe the other
(not coaxial) connectors pin count or connector identification, it would
be a start. If this was used on air-transport aircraft, the box sizes,
connectors, and connector pin functions are all standardized under
ARINC specifications. ARINC documents are available from them but
are very expensive to order from that industry group. The cabinet/box
sizes are described by "ATR-x" and slide into aircraft racks (also
standardized) and lock down through bottom front end pins.

Nevertheless, if anyone had any info how to connect such things or make them
work, would be appreciated.

VOR (Very high frequency Omnidirectional radio Range) uses a
combination of AM at 30 Hz (from the ground station antenna pattern
actually rotating at that rate) and a 30 Hz signal derived from FM
demodulating a 9.96 KHz subcarrier as the reference phase for azimuth
bearing to the ground station. There are many ways to show or compare
the two 30 Hz phases (automatic or semi-manual) and would be done in
a pilot's OBS or Omni Bearing Selector, usually a separate panel
mounting instrument. The "open space" from 30 Hz to near 10 KHz can
be used for voice audio from the air traffic controller to the aircraft or
for
automated airport condition recordings.

LOC or Localizer is also a sort-of azimuth bearing radionavigation
system but is specifically for the approach path azimuth for landing.
Uses only two tones and compares the amplitudes (equal when
centered on approach path). In most OBSs, the "left-right" needle
is switchable to either VOR or LOC but the audio signals for each
function are different.

From the basic VOR function, the receivers would have a 10 KHz
minimum bandwidth and tune 108.20 MHz upwards in 200 KHz
increments. LOC tunes from 108.10 MHz upwards in odd increments,
interleaved with VOR. Note: Later ICAO (International Civil Aviation
Organization) specifications may have 50 KHz increments in some
countries, but the even-odd interleaving still holds. AM demodulation
for both receivers.

If your receivers are modules that fit into a larger one, the
full documentation would have to come from the manufacturer.
Nothing secret about it...just isn't widely used outside of the
civil aviation world.

ARINC was first organized before World War 2 in the USA as a
private airline communication company ("Aeronautical Radio, INC")
but became a non-profit industry standards group after the war,
principally for airlines and air transport companies to allow very
quick substitution of standard communications and radionavigation
radios and indicators anywhere in the world.

Of course, I can redraw the wiring; although
that could take weeks

If you can't identify the receivers from existing website manufacturer's
photographs, that might be the unfortunate necessity. Try a search
on the Internet using "aircraft radionavigation radio" and see if anything
comes close.

Personal story: In 1947 at age 14 I got started in "real radio hardware"
by having to generate a schematic for the ARC-5 airborne radios sold
as military surplus...the new store owned by two long-time hams did
not have a reproducible schematic for less than a few dollars. Took
me a week-plus to do it as a beginner using an ordinary multimeter.
By then the store had obtained copies of the schematics, selling them
for much less than originally...:-) It was good training for me at the
time. In 1981 another engineer and myself had to generate several
schematics from existing PCB assemblies because a project manager
refused to spend extra project money for documentation. Together,
we cost the project a LOT more than the documentation and wasted a
whole month. :-)

Len Anderson
retired (from regular hours) electronic engineer person