618T-3 HF collins aircraft
radio, k0ip, collins military radio, 618T-3b, 714e-3, AN/URM-157, MRC-108 jeep,
mrc-95, 426T , 488A-2, 490t-1, maintenance manual 618T-3, MRC-117, mrc-108
military HF , forward air control radio
Collins 618T-3 Aircraft Radio.
- Ham Radio -
k0ip K IP
618T-2 page
A work in progress.
and the ARC-105 page,
This web's a collection of Books, Schematics, useful info, supplied by various 618T users,
When I was building my 618 system I had to search here & there to find
information. Somewhat frustrating at times, So I've tried to bring it
all together in one place. once I started then many of you (HAMS) send more documents.
How Good can it get, hams helping hams. keep that info
coming, ur pictures too.
NOW, if you see something in
ERROR, Please let me know so I can fix it ..
HELP !!
If you have any updated, PDF's of books, personal stories, or have any 618
and related equipment for sale , or
know a source of 618's, parts and pieces and accessories
please send me the info so I can
get it on this web.
my email is k0ip((at))k0ip.com call
208 251 6441
FYI: There's a Collins 618T User Group
!!!
A place to get answers,
stay in touch, and give help to others.
https://groups.io/g/Collins-618T
This user group is a great resource.
Lots of experienced radio techs ready with answers,, all
the manuals and
more....... sign up
today.......... |
Fellow Hams, especially DX visitors to the USA, Please,
BE MY GUEST
If your in the area of
Yellowstone National Park.
Stop in for a
Visit
My home in Pocatello Idaho is just off exit 69
interstate I-15, one of the main routes to Yellowstone, Jackson
Hole & Grand
Teton National Parks.
Stop by for a visit & some local Pocatello flavor.
I would love to meet you. Have an EyeBall
QSO , you can get out of the car
and stretch, have a
drink, coffee, beer, etc -
maybe more ?
your invited
try to give me a Heads Up -- if possible
call or write.. Otherwise just knock on the door.
tnx John
k0ip((at))k0ip.com call
208 251 6441 |
KØIP's home page --
Join me on Linkedin search john wilson
k0ip
LOOKING
FOR MANUALS
FOR THE MRC-117 RADIO SET ,
if you have any knowledge of the 117 radio set , ok,
your Not
sure what a 117 is ,, CLICK HERE
please contact wa0dyu(*)gmail(d)com or k5urg(*)yahoo(d)com
or w1nzr(*)cs(d)com
Here are books we are desperately looking for
TO 31R2-2-141 ORG MAINT MANUAL - AN/MRC-117 RADIO SETS
TO 31R2-2-152-1 CY-6177/GRC DEPOT SUPPORT, GEN SUPPORT
TM 11-5820-672-35-1 DIRECT SUPPORT, GENERAL SUPPORT FOR
CY-6177/GRC
TM 11-5820-672-35-2 DIRECT SUPPORT,
GENERAL SUPPORT FOR C-7186/GRC
TM 11-5820-672-35-3 DIRECT SUPPORT, GENERAL
SUPPORT FOR PP-4721/GRC |
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All Email addresses on this web have been modified to prevents Robots
from harvesting them from this web. protecting me and you..
Note: if you see (*) in an email address,
you need to change it to a @. and close any spaces, emails have NO
spaces. (d) is a period |
NOTE:
Most Pictures on this page can be ENLARGED by clicking
them !
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Want some Fun ??
Here I am screwing with the minds of the CCA Net control station
on the Sunday 20 meter net. some of them are very interested in my
strange sounding collins radio, but many are just semi-confused
about
anyone using a WW2 carbon microphone ,, say what , Carbon
???
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BACKGROUND STATEMENT..
Warning: I am not trying to tell anyone that I am an expert, I really have
little knowledge
about the radio's internal circuits, other than what
I can learn from reading the
instruction books and schematics. note there are many experts on
the user group listed above !!
I first saw one of these marvels when I went to a MARS
convention in
St Louis MO, in the early 60's. I was still in high school, and a new
ham... The Collins guy had a wire out a
window and was dialing in frequencies and talking with Cedar Rapids (?). This freq, then
that freq, then another, it was like magic WOW what a
radio.
If your old enough to remember. I had a 20A using a
ARC-5 command set VFO....
I never thought much about getting 618T on the air, until my
friend Math ON8PO convinced me I should do it.
(see his private military radio
collection at this link ON8PO
Truly amazing )
So I did, now I have two working units, one being the MRC-95 jeep
configuration.
I'm
now looking for a 24 volt jeep at a price that doesn't break my bank
account or my marriage .. HI HI
There are 3 versions of this radio,
none
of them are very user friendly as
far as the power requirements!
From what I know, the T3
is the only model that's easy to get power for, its
mostly brute force 24VDC (see below
24VDC) and a small amount of 115V/400cycle. However,
I have received letters from folks with large 400cycle motor-generators
powering other 618T versions .
The
400 cycle power is a problem, but nothing that can't be overcome.
see below 400Hz
Be
careful what you buy, I bought a 516H-1 thinking would make 400
cycles, it doesn't !!For a 618T3 What
do you need:
A big 28Vdc power supply and a 115Vac 400 Hz supply. the proper control
box.
You
can use the interconnect diagram and make a wiring
harness.
If I had it to do again, rather than using the URM-157
Test Harness as a control box,
I would have make a 19" panel with the control head and
whatever
controls / jacks I needed. Something like this picture would be deluxe
!!
This 19" control panel is sure sweet, it looks like a Collins product, I
don't have a
part number, but just maybe there are some of these floating around out
there in
radio land somewhere ????? Keep your eyes open at flea markets ..
Picture
from
VK3XAO
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These books are provided free for Amateur Radio use only.
Books
 
Webmaster:
this book provided by Luke AC5XP, Is the one to start with, and maybe finish with !. It has horizontal schematics, it appears to be the complete with addendums up to APRIL 1979.
THE LATEST, it is easy to read, the file isn't too big. very professional.
Collins 618-() Overhaul manual 15th Rev. Oct '79 optimized.pdf (13mb)
" Must have Schematics "
TM_116625-622-40.pdf
URM-157 with schematics
(very useful in running down where wires should connect, even if
your
not using the URM157, See pages 37 and 38 for the two models
of this test harness . The one on page is for the 618t B models..
(See pictures and description of the two units , down this page)..
618T-3 Interconnect with 180L-3
(Very Useful, in running down wires)
This is another , "MUST READ"
618T sales
propaganda book
especially the
last few pages,
which describes the radios various
configurations, and accessories..
426T1 400Hz power supply
book
488A 400Hz power supply
(note: the user group has lots more info about these power supply)
ARC-105
info
page LINK
from VE6ABW
490T-1 & 180L-2 & 180L-3A &
490T-4 Antenna TUNER INFO Page
Manuals below are linked to the Collins Collectors Association web,
618T-x_Maint_Parts_Tools TM 11-5821-248-34P
(CCA_Download)
(ARC-102, Not very useful)
618T-x_Gen Maint_Parts_Tools TM 11-5821-248-20P
(CCA_Download)
(ARC-102, Not very useful)
618T-x_Gen Maint_Parts_Tools TM 11-5821-248-12P
(CCA_Download)
(shows part placement in radio)
618T-2 in the C-141
aircraft
(CCA_Download)
(in-depth discussion of modules, how it works)
CU-168_FRR Coupler TM 11-5985-212-15
(CCA_Download)
(this is an obscure multi antenna coupler, not useful)
=====
And this book, covers the 618 plus many of the test equipment. in
some detail.
this download is (32 Mb).. Navy AN/ARC-94_navweps.pdf
=====
Also here are two book that cover parts of the AN/MRC-117 / GRC - 158
Radio.
SEE GREEN BOX at top of this page,, WE NEED other manuals, can you help
MRC117_TM
11-5820-676-12.pdf (47mb)
for the FILTER , which could have been used in other radios too ???
MRC117_Filter_F-1138_GRC_EXP.pdf (35mb)
======
Now here an interesting Collins sales book , covers all (?) HF equipment in the mid 60's
Collins-Communications-Equipment-1965 (7mb)
======
here is a page with info about the French 618... ER-104-A
from PAØPLT
==============================================
possible sources of radios, and parts
Murphy's -
BPB surplus - Columbia
Electronics international
William Perry Company 502-893-872
--
Ebay. -
for connectors check
Lasaero UK -
look towards the bottom of the page.
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For Sale Area.
& Wanted
for personal sales only
Some of the equipment that is presently be listed on the personal
sales page
click the button, for a better description and some pictures.
These listings are free, if you have something for sale, let the
webmaster know. |
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400 hz POWER SUPPLY
INFO
For more info about the power
requirements for the 618T-2 Please
see the 618T-2 page .. the 208V
isn't completely clear, it depends where you measure the voltages, , read the
T2 page.
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Collins 426T-1 400 cycle
power supply, this supply is used in the MRC-95
This is rated at 115Vac Square wave, 400Hz, 630VA
426T1 400Hz power supply
book
bigger view, Front
Back
EKCO STATIC INVERTER-E182
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Another Collins inverter, made for
the 618 is the 488A-2
488A 400Hz power supply book
one interesting thing: this supply plugs directly into the
390J-2B rack
(shown below, see racks)
also a T-195 Dynamotor
will probable work if its all you can find, as might
other dynamotor type devices .
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this 400 cycles Supply
DOES WORK, in use
its only rated at 150VA ??
$49 at Murphy's
STATIC INVERTER
from a reader of this web page
A source of a 400 cycle power inverter is the PP-2352 that converted
28V DC to 115V 400 cycles. They were used in the Jeep
Transceivers.
73, Bob - W0RY |
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And this GREAT 400Hz project
from Takashi JA6ATY
who powers his 618T with a modified
12 Vdc to 100Vac Car Inverter. Link
Tested and working !! |
Here's another one !!!
click for a better picture
 
This is a C.F. Electronics 700VA power inverter,
part number 200810..
This along with the EKCO E182 (above) must be direct replacements for
the 426T-1 collins inverter.. SAME plug and same size.
click here for TO in
PDF
supplied by WØGZV w0gzv texas |
400 Hz power supply
project
Take a look at F1FRV
web,
or this link for a download PDF
link
Thanks F1FRV -- F1FRV
web
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24 VDC
supply
One possible recommendation: shop Ebay for a Lambda
LRS-58-28 .. LRS-58 model..
Shop the "Auction's only", for
better prices..
a note from a 618 owner: I have this
power supply running at 25
volts, it just sits there
quiet as a mouse even in TX Tune mode. It can
be turned up to
almost 27 volts before its internal over-voltage
protection circuit
trips.
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Here's some info i grabbed off the "group.io"
I found this on eBay:
https://www.ebay.com/itm/184645036684?var=692365815317
It can deliver 62 A peak (at 24V). I felt the price to be fair, so I
ordered one. It arrived well packaged, and pretty fast for a China
order; within 3 weeks. Turns out it works great with the 618T-3 radio
Quality of build is excellent. It is a 24V PSU but
there is a trim pot on the right side of the terminal (barely visible on
the photos) which allows you to adjust it to 28V (which the pot reaches
without a problem with room to spare)
It is specified for 62A which might be a bit less
when tweaked to 28V, but I can now modulate my 618T-3 fully (delivering
430 watts PEP in SSB) without the DC voltage dropping in any way
They sell two models, 100-120V AC and 200-240V AC, which means also good
for use in the UK (assuming you order the right model of course) |
webmaster
comment: I went to the link on the left for these supplies and
only found a few, I had to look at several auctions before I
found one that runs on 120VAC ..
I
suggest you search for
AC DC 1500W 12V 120A 24V
60A 36V 40A 48V 30A Industrial Switching Power Supply
NOW,, if you view AC5XP's
video, he says
these are fairly RF noisy.
and suggests a PULS SL-20.
continued just below
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So AC5XP uses 3 of these in parallel, to give him 60amps
they are adjustable to 28 VDC and Luke says they are RF quite..
I looked these up on ebay, the prices are ALL over the place,
some as low as $75 each to hundreds each..
these are PULS SL-20 supplies, |
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Control Heads
Control Head, be sure to read "618T sales".
You can
learn a lot about the correct parts and pieces for this radio.
There are lots of control heads on Ebay, most are priced "out of sight".
If your in a hurry, buy a good one, otherwise
I say, take your time and
keep looking
for one at a reasonable price. |
This is the 714E-3 Control units,
I am not sure how it differs from the C-3940/ARC-94 (to the right) it
looks the same on the front .
There appears to be a wide variety of various part nr.
714E-1
714E-2/-2A/-2B/-2C
714E-3/-3B/-3C/-3D/-3F/-3G/-3H
714E-6/-6A/-6B
another slightly interesting item , a test set for these
heads
ASI-162
link on web link anyone out
there have a real picture of this test box ?? |
Military heads that works .. click
it
There may be more heads that work , however, this is the only ones I
know about .
C-3940/ARC-94
Click Front or
Back view ,
_____________________________________
here's a picture of the front
and back of the
714E-2.. (commercial) it has a
different connector than
the Military units. click pictures to make them bigger.. note lack of CW
and Data modes
pictures from K7APO |
This is the 714E-6. It' s for the
618T-3B
Note the 100hz digit
Click Front or
Back view, bigger |
PLUGS
Getting the plug for the back of the Radio?
THIS is a major problem !!!!!!!!!
When I built my radio setup,
I could have attempted to purchase the female plug for the back of the radio, but
I wanted to sit the
radio in a rack, so I purchased a brand new retro-fit rack 49-T4. This
"retrofit" trick is used so the
aircraft Weight and Balance doesn't need to be recomputed. and the old
aircraft wiring works.
This saves the aircraft owner a lot of money.
the female that mates with the radio,
Cannon DPE-60-33s, a 60 pin
connector. you might check for
DPE-60-33S-A101 |
Here is the female that mates with the commercial (?)control
heads ,
at least the 714E-2
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the female that mates with Military control head, Cannon
20-39 (at least that's what mine says) |
the female that mates with the 426T-1 400Hz supply ,
Cannon DPX-32-02-339 |
bigger view |
Looks like Amphenol 4 S81 ?? |
bigger view |
bigger view |
NOW, for the URM157 test harness
the DC and 400hz AC plugs.
My URM157A has a 5 pin plug for the DC, however it appears that
most 157's only had a 4 pin connector ???
make sure you know what you need
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AC in 4 pin Amphenol
MS3106A-18-4S
DC in Amphenol
MS3106A-22-22S
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The 18-4S connector is Mouser part number 654-973106A184S
The 22-22s connector is Mouser part number 654-973106A2222S I like
EBAY, shipping is always a killer to overseas locations,
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if you have more info about plugs or any of these numbers are
found to be incorrect, PLEASE let me know.
note: some of the companies I have listed above, to the right, sell these
plugs, HOWEVER, I think they are thieves, asking $200 or more for a
connector !!
if you find the 60 pin connector for $50 to $100 dollars, that's probably
fair, any more and someone is trying to take advantage. If you discover a
source that's fair
buy them all, I bought 7 of these for around $55 each, and sold them
on this web for my cost + 10%, , the six were gone within a few months. now I
have a free spare for my
next project !. Note: I only have one spare, I don't horde .
| RACKS |
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note: the 618t must be elevated
, as
forced air escapes from
the bottom of the radio. |
49-T4 Retro fit rack
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Note this looks like the rack below, but its not,
needs external 400hz |
 This is the 49-T4 Retro fit rack .
Note: the WIDE sides..
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 Also
390J-2B PART 622-1253-001
click the picture to make it bigger
you can see, on the top, a small connector
that mates with the 488a-2 inverter.
This was listed on Ebay as coming out of a Helicopter |
TEST SET's Proper name ""
Test Harness, Radio set AN/URM157""
Please NOTE: These are great to have, There are
2 different configurations, the older units, on the left
has
a toggle switch to select the type of control head, it does not work
100% with the 3B model radios, it
works except for the 100 Hz switch. there are no wires connecting
the 100 hz switch.
The unit (right) has a rotary switch (bottom row of connectors and
switches) IT does include wiring needed for the 3B radio. IF you get the
entire test set, it comes with all the cables needed to connect
all the
618t parts and pieces together. SO other than needing the Power Supplie(s)
you've got what you need to get on the air .
Note: many of these sets have been scavenged for the cable that goes
between the radio and the Harness.. Look Out when buying |
AN/URM-157 (Test Harness)
higher RES view, Another
hi-res view
note:
The URM-157 test set is for all three 618T models, I've heard that
selecting the wrong radio might cause smoke ?? Probably nonsense
??? But as with everything, be careful to plug the radio into the
correct connector, and select the correct radio & control head before
applying power |
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(Test Harness) later version TS1949A/ URM-157A
This unit works with all 618T-x versions including the 3B and its 714E-6
head.
Note: rotary switch in bottom row, it selects the type of control head to be
used.
also, the cable is labeled 714E-3/6 so whether this cable works
with the E1 or E2
heads is an unknown .
Heres a PDF that covers both models
TM_116625-622-40.pdf
a bigger view of this picture ,
front controls close up,
top plugs close up. |
618T-3B
Late production commercial units
The 618T-3B
model does 100hz steps, It has a different synthesizer.
The 3B was introduced at the end of the 618T's production and was only offered
for commercial service.
Since the 3B radio was never offered to the military, the
military AN/URM-157 (Test Harness) is
not wired to accommodate 100Hz steps even if you
have the 714E-6 head. The military test set only
test the 714E1, 2, 3 control heads, which are not all wired the same !
make sure to select the proper head.
Please see discussion about various URM-157's just above....
the 618t-3B has 4 extra connections that control the 100hz steps
W on the head to 20 on
the radio , X to 21 , (lower
case
k ) k to 22,
(lower case j ) j to 23 .
a 618T-3B it will work using a 714E-3 head,
however there are NO connections
for the 100Hz control wires. If you just let them FLOAT you will be off
frequency.
There is a matrix in one of the books showing how the
100hz switch works, none of the possibilities
are all open,
I suggest you ground radio pin 23 and leave 20,21,22 floating, this
sets the 100hz step to zero
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(note 1) looking at
the
interconnect diagram it's a little
hard to make out some of the pin numbers !!
here is a picture of the connector that plugs into the back of the control box
as well as a picture showing the radios pin out..
some confusion: the radio
plug pin 24 goes to ' i ' on the control head .
it looks like there are 2 pins that are labeled number 16 --
NOT so, 16 is to the left of 4 and 18 is to
the left of 60, look close
-------------------
Note: the pins on "this diagram" and the pins on the
"interconnect draw" are not in the same ORDER
,,, Heads up ! don't get confused
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OK, Guys, be careful, some of these designations
are confusing,
The "wire" designations are not the same as the PINS on the
control head
connector !!
here is 3 different views of the same thing
1. <--- to the left, is the
radio connector
2. below is cut from the
TM_116625-622-40.pdf , listed above under BOOKS
which contains
the complete diagram of the Test set, it is very helpful.
3.
618T-3_interconnect_
click to enlarge the picture This is
the control box connector
for the Military C-3940/ARC-94
This is the plug that mates with the military control head
THIS is the connector for
the (???) commercial 714E-2 control box,
No bigger pins and a completely different metal shell.
click it to make it bigger
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Other Webs with 618T information |
* from a British group, which you can find if you
just google collins 618t some
good info heres a link to their PDF
https://secure.toolkitfiles.co.uk/clients/22828/sitedata/files/618T_SIG-1.pdf
* look down this link for the "618 overview"
http://www.austradesecure.com/radschool/Vol32/Page5.htm by
VK3XAO
he has some interesting pictures of a base station rack.
*ARC-105 sales propaganda sheets Plus More The
ARC-105 is a pressurized 618t for use in military aircraft,
* an/mrc-95 forward air control system
http://www.afdasf.org/dasf.html pictures are listed in
sections by the guys that took them,
Lots of great pictures
of military life, some of radio jeeps, but you have to spend a lot
of time looking.
it is the source
of the information about the MRC-108 Jeep is
KV4AL
* PA3GON several military radios and
other information.
http://www.aviation-radio.com/
* Info I found from F6BIR, its all in French , looks like a home
brew 24 V and the 400 hz supply
check it out
*. more pictures of the MRC-94,
MRC-108 & MRC-107 link
1
2 3 4
* Interesting site: F1FRV has a LOT of info up about the 490T1 antenna
tuner, pictures, downloads
covering
everything about the 490T-1 and the ARM-109 test set and info about a 400 hz
supply , plus some of his home
brew interface units ,,
LINK
Here is a list of non-618t webs about things I find
interesting !
*
Almost anything military ON8PO pictures
http://www.mil-com.be/
* Crypto Museum, This site has a LOT of info, almost too much to digest,
very fascinating..
http://www.cryptomuseum.com/
* Need info about a lot of military radios, got something to
share with these guys ??
http://radionerds.com/index.php/Main_Page
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AN/MRC-108
MRC-108 ROMAD , Forward Air Control Jeep,
click the pictures to make them bigger
H.F. Transceiver was a
AN/MRC-95 by Collins Model Number 618T3, 718F-1 coffin, 313V-1 control
head, 618T-3 radio, 426T-1 power inverter,
460D-1 load coil, 670D-1 tuning
coil, 76F-3 speaker. The HF Antenna was 32 feet tall mounted with a rubber
boot for protection to people passing by so that
they would
not receive RF Burns. This antenna reduced to 10 sections the width of
the jeep. This antenna is a Shakespeare 120 HF Antenna,
NSN: 5985-00-846-6442
Military nomenclature: AT-1011/U and is still available from the factory in
South Carolina.
Here's a
link to a nice picture and complete radio run down, by
Capt.
Burt Blatter. their home page
http://www.afdasf.org/
first two pictures are pulled from
http://www.qsl.net/ik0moz/admm_intern.htm
more pictures of this configuration at
http://www.hypertools.com/pix/pix.html (down the page )
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click for a better picture VC-102 HF communication system
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AN/MRC-117
AND NOW here's another one,
the AN/MRC-117 as used with EusCom Command Network
in Europe from 1976 to 1984 .
Click, here's a story ! from an actual user
of this system ,, WA9Z
here is the only TO I have on the mrc117,
its only covers the mechanical mounting to the truck , no electronics
TM
11-2300-370-15-1.pdf
Below are some pictures of the control head used in this system ,
more pictures and a story see
LINK
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a note from WA9Z ,
Is this thing cool or what?!!
It mounted
on a pedestal between the front and rear seat. There is (was) a removable
cover on the control head that had a compartment to store audio accys,
pens paper, etc.
There were privacy curtains on the rear windows and between the front
and rear seats, and red lights for cab illumination. The operators had a
small desk to write, hand microphone, 2 headsets. and a J-38 on a leg
iron. As you can imagine, pretty cramped quarters.
Every time a truck deployed the head was installed, and removed when the
truck was motor pooled.
As such, I spent most of the time repairing the plugs and sockets.
Haven't seen one of those since 1979. My research leads me to think
there was only a few hundred of these ever built for the
Pershing II quick reaction teams.
click it to make it
bigger
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more pictures and a story
see
LINK
click it to make
it bigger
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In the AirForce, these radios were used in so many aircraft, I don't know
if I could list them all, plus I don't know them all !!!
but for sure the C-141 , C130,
Also Civilian aircraft, 707's to the Concord
IN THE NAVY,,? do
you have any pictures or info about Navy installations.. please send to
webmaster,, tnx
HELP SECTION , WE have questions
anyone have any ideas or info,, these look like the MRC-95
control heads But they are Gray, indicating NAVY ?? ,
these two boxes have slight
differences.
Do you know what radio this type of control box was used for ???
take a look there is a difference something to do with filters,
313V-2
and
313V-2A
here three PDF's to help with this control boxes,,
313V-2 Manual.pdf
313V-2 Schematic.pdf
313V-2 Test Set.pdf
Fast Patrol Torpedo Boats / PTF-17,
click pictures to make them bigger
note the big whip , mid ship,
N6CC
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More info link N6CC
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| TSQ-108 mobile radar station, |
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the Navy TSQ108...Mobile Inshore Undersea Warfare Unit
1920 sets up the AN/TSQ-108 Radar Sonar Surveillance Center (RSSC) van
at Mare Island CA. Keeping watch – a training exercise circa 1980.
more info
LINK N6CC WAY MORE
INTERESTING INFO AT THIS LINKRadar, sonar, sonobuoy receiver/ recorder system, VHF R/t x2, and 2 each 618T-3 in a "hut". and 2 whip antennasthe tuners were at the antenna.
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More navy info, from
David Stovall
I used to work on them in the Navy and got a job after the Navy because
I could repair them.
The ARC-94/RT-618T2 was used in the P-3 Orion while the
ARC-102/RT-618T3 was used
on the SH-3 Sea King and the
ARC-105/RT-618T1 ( it could have also been
called: ARC-105/RT-712) was used on the EA-6B
Prowler.
I have no pics because I'm pretty sure that
would have gotten me courts marshaled.
I still remember some about
them. Because they use mechanical tuning, they scared a lot of
techs into believing they were more complicated than they were. Most of
the time when a transceiver came in to the AIMD
(Aircraft Intermediate Maintenance Department), they
weren't so much broken as badly out of tune.
Anyway, if I can be of assistance, shoot me an email.
ddstovall((at))charter.net
David Stovall |
SH-3 Sea King ARC-102/RT-618T3
EA-6B Prowler ARC-105/RT-618T1
P-3 Orion
ARC-94/RT-618T2
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In the Marine's
Here's a letter received June 2019
Hi. My name is Ray Fellows. I live in Midlothian, Tx, just south of
Dallas-Fort Worth. I ran across your web page and it sparked up old
flames.
I repaired these radios while I was in the Marine Corps, around 1999 to
2003. I repaired more than my fair share of them.
When I checked into my command after school, there were 22 of these
radios waiting to be repaired. No one was working on them, no one
knew how.
I took it as a challenge. I dedicated my time in the Marines to HF
and no one messed with me. I worked religiously learning as much as
I could. After about
a year, I had all of those radios fixed. I got orders to Okinawa for
6 months. When I got there the SSGT (boss) asked me what I worked
on. I said HF. Well
I inherited 17 more radios to repair. I got so good a fixing these
things. I would read the theory of operation and study schematics on
my free time. I can recall
being so excited when I found out how to get the 3.5 Mhz oscillator
to finally lock. I ran to a friends room in the barracks, barged in
and hollered its the Kstab.
You have to align the Kstab first! They thought I was nuts and I
suppose I was.
I attached some pictures of photos my mom took of me when she came
to visit our shop way back when. I still have all my old notes,
procedures, schematics.
I was so passionate about these radios. I sure do miss them.
I am an electrical engineer now at Texas Instruments. When I saw
your page, I immediately began searching for a radio on ebay.
Nothing yet, but when one
comes around for the right price, I am going to snag it for sure. I
obtained my FCC General Radio Operators License when I was in the
Marine Corps. I
suppose if I wanted to talk on a 618 I would need a bunch more,
antenna, control box, coupler?, power supplies, etc.
While in the Marines, these radios were referred to as "94's" or
"102's". I am sure you understand the references but AN/ARC-94 used
the 27.5 Vdc power
supply and the AN/ARC-102 utilized the 115 Vac 400 Hz supply. The
first squadron I was in supported helicopters, the CH-53 and CH-46.
The "94" was installed
on these aircraft. The second squadron I was in supported CH-53,
CH-46, and C-130's, among other aircraft also. The C-130 used the
"102". It was important
to make sure when you built a radio that if you were filling a 102
hole that you remembered to update the keying in the back of the
radio or it would not plug into the aircraft, ask me how I know.
heres RAY,, at his work
bench,
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CH-53E heavy lift helicopter
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CH-46
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Sorry Ray, I couldn't find a good shot of a Marine 130
this one belonged to the USAF
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Possible First product review ??
Collins Signal Magazine 1960.
click to enlarge .
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How about an AIR DROP ??
click to enlarge
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Heres some interesting pictures from the collins PULSE company magazine
some interesting reading, lots to look at see
http://rockwellcollinsmuseum.org/collins_pulse/index_a-z.php#6
click to make it bigger,
1. MRC-108's all in a row
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2. 618's on aircraft
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3. see Collins Canada, click to make bigger
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Operational 618T's Hall of Fame !!
send me your pictures and letters
One left click on most pictures enlarges them !
ON8PO - shown with
antenna tuner , home constructed box for
control head and mike and earphone jacks , in a nice transportable display
http://mil-com.be/
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JA6ATY
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One left click on most pictures enlarges them !
PE1RKS
On the right a 618t that I have build into a case so I could take it
with me at field days, 400Hz is generated by the black box inside the case
on the right.
On the left you see a MRC-95 that is based on the 618t with the 426t
400Hz inverter.
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Some detail of the homebrew transportable 618t
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Front of the AN/MRC-95
Internals of the AN/MRC-95
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WA9URJ
Here is a picture of my test set-up.I am using a 40 Amp Lambda
switching supply for the main 28 volt dc source. The 400Hz inverter is
driven by a separate smaller linear supply. I built a panel to hold the
control head and other switches and jacks. I have ordered .050 aluminum
to make side panels and will eventually make a mount to hold the radio.
Here is a picture of the test set up, all mounted on a cart for easy
access in the shop.
This is really a great radio and meets the requirement that "real
radios have motors".
Many thanks for all your assistance. My next step is to get the
operational level to the point where I can check into the local 40 meter
AM net
73's Geo. |
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some comments from Leighton GW3FSP:::::
Hi John
Just thought I would let you know the 618t is not dead here in the UK !.
I worked for British Airways until I retired 2 years ago, about 2 years
before then I was given a 618t complete with all the mounting cradles,
cabling,
control heads, 180r tuner and control system, spares and all the test
equipment ( extender units etc ) when BA no longer had any 618t sets in
their fleet,
these were fitted to the early 747 ' Classic ' or 747 - 100 a/c and of
course the Concorde aircraft, it was originally fitted with the 3 phase
400hz 115
volt ht supply, however I managed to pick up one of the 28 volt supplies
from Ebay, ( The A8 module, )
The radio I have will tune to 100hz, so I had to add the extra control
wires from the mounting frame to the control head, to get the tuning to
work down
to 100hz, I also had to modify the power supply wiring on the mounting
frame to allow the use of the A8 power supply and also fit the extra
wiring inside
the 618t for the 28volt dc supply, I was also lucky to ' acquire ' a
7amp inverter supply unit from the same source, this is an ELGAR
inverter supply unit
which supplies ac from 10 hz up to 1000hz at 7 amps. this I use to
supply the 400hz 115 volt supply to the 618t.
I then bought a 42 amp 28vdc switch mode power supply from Ebay which is
used to float an ex aircraft nickel-cadnium 28v battery
( again from BA ) when the radio is in use, it takes a good 38 amps so
I'm told when on TX.
And after squeezing the whole lot under my shack bench - it works !, and
I have to say it works very well!, rx is very quiet with almost
no internal noise, the noises thing with the radio is the little cooling
fan mounted in the front panel for internal cooling which revs up when
on tx.
and howls away merrily, it really warms the shack after running the set
for about an hour, on ssb I get excellent reports of speech quality
using
one of the Seinhauser aircraft headsets I also ' acquired ' with a
little whine audible from the 28 volt inverter supply on tx audio, apart
from that
I've had no adverse reports .
Hope you are enjoying your hobby, I know I am. 73's Leighton Davies
GW3FSP ps I'm in QRZ.com |
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some comments from Bob
K8RJ about his radio ::::Just stumbled
across your very interesting page on one of my most favorite
radios. Lots of super info.
I am Bob K8RJ, started as K9ITS in 1957 in Chicago , spent 18 years out
in Orange County California and now live in Michigan's UP.
My first 618T-3 was one that I obtained in a government auction back in
about 1967. At the time it was just a black box on a pallet full of
other surplus stuff. Back then when I had the need for manuals I could
go to the Great Lakes Training Center library as a civilian. Lots of
things
have changed since then, this is no longer possible. Anyway. all I knew
about it at the time was it seemed to have two 4CX250s and their
sockets and I was thinking of nice linear material. I nearly fell off my
chair when I read from the manual what it could do!
I was hooked. At the time with a wife, three kids, a mortgage and a
full-time job at which I traveled a lot I could not afford the real
Collins
control head or power supplies. But, I did spring for all the Collins
manuals and set about getting my 618T-3 on the air.
Back in those days there were many electronic surplus outlets in
and around Chicago. I managed to build a brute force 28VDC supply using
several huge high current filament transformers with wired
series/parallel secondaries, got some 200amp diodes and some computer
caps for
filtering. For the 400Hz at 115VAC I started with a rotary inverter ---
nasty!!! Then I lucked into a nice SS inverter at a hamfest to do the
job.
Then, I could not afford a real Collins control head by a long shot.
But, I had access to many multi section rotary switches at these surplus
stores.
So, I decided on a Nixie freq. readout and display. I built the display
into an old Heathkit defunct Hi Fi amp cabinet that I bought at a ham
fest
for a buck. I had to buy the actual switch section from Collins for the
MHz codes and Nixie display. I wired up the other switches to do the
needed codes and used a separate section on each switch to light the
Nixies. Lotsa dollars for those Collins MHz switch sections; but much
cheaper than a real control head. So, I wired the whole thing up and it
worked like a charm. Looked great too. I'll bet the ONLY Nixie readout
control head for a 618T-3!!!
Eventually I figured out why it likely was surplused out by the Navy. It
would only transmit for a couple of minutes then drop off the air. I can
imagine that it worked well on the bench then on the aircraft it would
drop out, back to the bench and it worked well, etc. So, I scouted
around
the surplus stores until I found a suitable relay and it worked
perfectly with that one for many years. Eventually I sold the entire rig
to a local ham
who just had to have it and who had deep pockets . . .
A few years ago I got the bug for one again now that I am retired. I
bought one from a ham in Washington State. Obtained power supplies and
a 714E-3 control head. I found the test set at Fair Radio, some power
cables and the test set to radio cable with the 60 pin connectors at
each end
from a surplus dealer on the internet.
Much to my disappointment when I put power to it, it was DEAD DEAD
DEAD!!!
Did some checking and found that the 18VDC power supply was at zero
volts. I eventually found the problem to be a shorted electrolytic cap
in that power
supply. A $1.20 repair part. BUT, US parts suppliers wanted upwards of
$10 for shipping of this little item. So, I checked on ebay and found a
lot of five of the
exact same caps listed by a seller in Rumania -- American made new Kemet
caps at that for just $5 USD delivered. That 618T-3 works very well now
after
I did a little tube replacement and alignment.
My very first on the air contact with this one happened to be on
40meters with a fellow ham who serviced them when he was in the US Navy.
Since then I have acquired five more 618T-3s one of which receives OK;
but, does not transmit. I suspect an incorrect wiring issue in the tray
to control
head line. This is my current project. It has the mobile type control
head. I have not yet tried the others.
My goal is to eventually get them all up and running. I have enough
control heads, five trays or interconnecting cables, two test harnesses,
a 490T and
another Collins tuner for them and the module extender set.
I once again have a pretty complete manual set.
I used the sources that you listed on your 618T page as well as Newark
for some of the connectors. Fair Radio was a very good source. But, I
did find three of the trays on ebay. Two of them were only $30 each
complete with the 60 pin connector; BUT, shipping from Australia was a
REAL killer!!! Sigh --- as they seem to be made of unobtainium one has
to pay the price.
I am very sorry that this is getting so long. But, maybe some of this is
of interest to other 618T () users. I am no expert just lucky; but, if
any
one has questions, I would be happy to try to help them.
73 de Bob K8RJ |
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IZ2FLX
Dear John,
congratulations for your web site, I found many useful Tips when
restoring my AN/ARC-102.
Thank you so much and I'm happy to send some foto's of my 618T-3 . |
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.jpg) Hi John,Yesterday, I came across your beautiful WEB page. As you and others, I have the 618T illness. It isincurable, I have also contracted the MRC-108 illness. I am pretty sure that the 618T illness is a strain of the 400Hz virus. Frank, KF5RXV
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Carlo IK2CNC
, has two 618T's fully
functional plus lots of other goodies.
I had three pictures, and loss them (somewhere) got this picture
form QRZ
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Lampros SV8FCF had
his 618T up and running, |
home brew 28vdc to 400 cycle converter,
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Lampros also has a jeep, maybe some day he will get all the parts to
make a MRC-95 mobile installation ??
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Roger F6FER
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The 618T-3 is placed on two aluminum angle pieces fixed to a
mounting base plate in the bay.
Low voltage power is supplied by a pair of Lambda 28V-23A PSUs,
one supplies power to the transmitter section of the transceiver, the
other one feeds the receiver section and utilities.
The 110V-400 Hz is supplied from a home made pure sine inverter.
The control box is a 714E-3, and is inserted on a home made 19" mounting
panel with jacks for Phones, Mike/PTT, Key, Data input and a
switch
for the pilot lamps.
The set up is completed by a Collins antenna coupler CU-351/AR
and a home made VSWR meter.
I was lucky enough to get the rear connector for the transceiver
and the circular connector for the control box, it is not easy
to find parts at a fair price in France. All remaining mounting, wiring
and connections are home brewed.
I have 2 other T3s, one is OK for reception, the other one is out of
service.
Food for trouble shooting.
I am not an expert, just a lover of these Collins beasts.
73
Roger F6FER |
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Paolo IW6BET
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Dear John,
I want to thank you for your help and your
patience.
My 618T-3 is working well, I used it in several
QSO with no problem, excellent frequency stability, good output power.
The only problem that remains to be solved is
the fan noise, but I think there is no solution! After all, it is part
of the charm of the radio!!
Attached you will find a photo of my setup, I
hope you will like it.
Thank you again John, I hope to find you on
frequency.
73 de Paolo, iw6bet |
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WA3KEY
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Here is a photo of my Collins airborne station at my newQTH in California. I have two of the 714U-5M's - one pictured and another in my garage. I still have three 618T-3B's plus I found a second test box that supports 100Hz steps plus another 714E-6 control head just a few months ago in England.73 de Norm - WA3KEY |
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If you want to send pictures, emails, anything , just send to
k0ip(at)k0ip.com
some of the PDF's on this page came from
http://www.liberatedmanuals.com/all.mpl
wheres there's MANY US Military manuals.
LOTS of military radio system manuals are at
http://bama.edebris.com/manuals/military/
I hope this page has helped you in some way to make sense of all the parts and
pieces of the 618 radios. please contact me if your in my part of
the world, for
a eyeball QSO at my house, , see the info at the top of this page
