Bruce in Alaska wrote in news:bruceg-
:

May, or may not, be true, depending on the Radio Design. Type Acceptance
does NOT define the design, it only specifies the Stability.....



There's no oven in the M802. I have a high stab compensated xtal
oscillator in my Yaesu FT-990AC and FT-900 radios. Sync to WWV on 10 Mhz
drifts less than 2 hz in a year, even on the FT-900 in the car. I don't
think anyone uses xtal ovens any more. Solid state compensation works
wonderfully without loading down battery systems with heaters.

WSB-AM in Atlanta used to be about 2.2Hz low in freq on my FT-990AC....(c;

Sorry, I worked in government calibration labs from 1966 to 1988, even at
sea. Old habits are hard to break. If you see a Navy cal sticker that
says CNSYD Metrology Lab on it. Look for the 08 on the stamp...that was
me...(c;

Larry
--
Vista has been out a week.
Is Service Pack 1 ready yet?

"Larry" wrote in message
...

There's no oven in the M802.

Yes there IS. It uses a CR-604 OCXO. That's Oven Controlled Crystal
Oscillator. It uses a resistive heating element operating directly off the
HV supply.

Eric

In addition to the M802, the following marine SSB's also use an OCXO. Icom
M700, M710, Furuno FS-1503, and the SEA222.

Eric

"Eric Fairbank" wrote in
:

In addition to the M802, the following marine SSB's also use an
OCXO. Icom
M700, M710, Furuno FS-1503, and the SEA222.

Eric




Now you've got my curiosity up. I've emailed Icom to find out and try to
wheedle an M802 schematic out of them I used to get free with ham
equipment.

Larry
--
Vista has been out a week.
Is Service Pack 1 ready yet?

I'll save you the trouble. I just threw together a web page with three
images from the service manual. I have one as I have done repairs and
adjustments to several of these radios. It's my job as a marine electronics
tech.

The first pic is the block diagram of the PLL circuit, the next one is
from the main block diagram that shows the reference oscillator (OCXO) that
clearly shows the HV supply feeding the resistive element of the OCXO, and
the third one shows the schematic portion with the OCXO in it.

Eric

"Larry" wrote in message
...
Now you've got my curiosity up. I've emailed Icom to find out and try to
wheedle an M802 schematic out of them I used to get free with ham
equipment.

Oops, got a little too fast on the keyboard:

http://home.comcast.net/~fairbank56/ocxo.html

"Eric Fairbank" wrote in message
. ..
I'll save you the trouble. I just threw together a web page with three
images from the service manual. I have one as I have done repairs and
adjustments to several of these radios. It's my job as a marine
electronics tech.

The first pic is the block diagram of the PLL circuit, the next one is
from the main block diagram that shows the reference oscillator (OCXO)
that clearly shows the HV supply feeding the resistive element of the
OCXO, and the third one shows the schematic portion with the OCXO in it.

Eric

"Larry" wrote in message
...
Now you've got my curiosity up. I've emailed Icom to find out and try to
wheedle an M802 schematic out of them I used to get free with ham
equipment.

In article ,
"Eric Fairbank" wrote:

In addition to the M802, the following marine SSB's also use an OCXO. Icom
M700, M710, Furuno FS-1503, and the SEA222.

Eric



since the SEA222 has been out of production in the US for almost a
DECADE.... I wonder if you consider it a MODERN Marine Radio????

Bruce in alaska who was around, when the SEA222 was being
Type Accepted........
--
add a 2 before @

Bruce in Alaska wrote in news:bruceg-
:

Bruce in alaska who was around, when the SEA222 was being
Type Accepted........


Old fart. Remember those little Raytheons with the pilot light in series
with the antenna wire so you could tune the coil taps?.....Yeah, you
remember...me, too....(c;

Larry
--
Vista has been out a week.
Is Service Pack 1 ready yet?

In article ,
Larry wrote:

Bruce in Alaska wrote in news:bruceg-
:

Bruce in alaska who was around, when the SEA222 was being
Type Accepted........


Old fart. Remember those little Raytheons with the pilot light in series
with the antenna wire so you could tune the coil taps?.....Yeah, you
remember...me, too....(c;

Larry

Oh Yea, and I carried a RF Ammeter in my Travel Box, to do ReTunes
on ALL the Old AM Marine Radio Systems, scattered all over Alaska,
and the Boats floating everywhere in the North Pacific.......
How many Marine Radiomen still alive remember using an RF Ammeter....
Old Chief Lynn??? maybe........

Bruce in alaska
--
add a 2 before @

Bruce in Alaska wrote in news:bruceg-
:

How many Marine Radiomen still alive remember using an RF Ammeter....
Old Chief Lynn??? maybe........



After restoring the TBK transmitters aboard USS Everglades (AD-24)
(started at end of WW2 but not completed until Korea broke out), and
tearing down and rebuilding the antenna structures between the aft king
post yard arms and main mast yard arms, some serious wire antennas, I had
a problem on many freqs Radio asked me to put them on....too MUCH antenna
current for the hot wire ammeters in the tuner on top of the transmitter.
(It transmitted into a single terminal in a trunk overhead with a copper
pipe on porcelain insulators through a grounding knifeswitch in the trunk
to a big brown feedthru insulator out to the longwire monsters, making a
lazy L antenna laying on its back...very long.

After burning up a couple of hot wire ammeters, I decided to parallel two
of them, one inside the tuner and one that showed through the panel in a
window so you could read it. The whole meter was at RF hot! I put "X2"
on the window with a labelmaker to remind anyone of the unauthorized mod
noone cared about....or these old beasts in Radio II.

Man, with a little care and cleaning the TBKs and TBMs could turn the air
blue around those wires! I spent many a fun night on 75M AM (plate
modulator was a separate audio power amp in series with the DC Motor-
Generator providing plate volts to the finals) and on 40M CW from the
test local operating position in Radio II aboard "Titanic". To have the
feel old radio operators must have had on their ships in WW2 was simply
PRICELESS. The blue arc from the key contact, themselves, was most
impressive.

WARNING to DECK FORCE: DO NOT REMOVE GROUNDING WIRES ON RIGGING ABOVE
DECK WITHOUT TALKING TO ET1 BUTLER __FIRST__!
(Many got burned...(c;....It makes ya SO proud!)

Larry
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Vista has been out a week.
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