The RÐ390A Owners Manual

by

Chuck Rippel, WA4HHG

Congratulations!

ÊYou are the proud owner of a Collins designed R390A/URR general
coverage, HF radio receiver. In many circles, the R390A is considered
to be the finest HF radio receiver ever built. Weighing in at 85 lbs,
this electroÐmechanical wonder was designed in the early 50's and
released February 24, 1954 which also happens to be my birthday.
Thanks to features such as a 6DC6 first RF amplifier, a suite of
Military Grade Collins mechanical filters and full tracking RF and IF
sections, the R390A is capable of copying signals down to its Ð143db
noise floor, close to the galactic limit. All this while operating in
high over load/strong signal environments.

Originally built by Collins Radio Company in Cedar Rapids, IA, the
R390A was designed by 2 teams. The mechanical team being lead by Fred
Johnson while the electronics team was overseen by Ernie Pappenfus,
K6EZ. Besides Collins Radio, there were 13 other subÐcontractors which
built R390A's until the last one rolled off the assembly line in 1984.
Banks of these fine radios served the country in all branches of the
military and also the CIA and NSA for monitoring communications from
behind the Iron Curtain during the Cold War years where the R390A was
classified TOP SECRET until the midÐ1960's. Stories are told that
R390A's are still in use by the NSA where senior operators far prefer
their quiet, yet stellar performance over modern, megaÐdollar
receivers from Harris, Racal and WatkinsÐJohnson.

I hope you enjoy this wonderful radio, unduplicated in performance and
rich in history over the many years of service it still has to offer.


Ð73Ð

Chuck Rippel, WA4HHG Collins Collectors Association


Care and Feeding

Before powering up the receiver: There is nothing really very
different about owning and operating an R390A but there are a few
issues to be aware of. By now, you know that this radio is quite
heavy! Weighing in at 85 pounds without the accessory cabinet, your
R390A is a "boatanchor" in the truest sense. Keep this in mind when
considering a location and operating position; placing it on a light
desk or TV table might result in this 85 pound radio ending up in your
lap! Another consideration is the amount of heat given off by the
R390A's 26 vacuum tubes using both 6.3 and 12.6 volt filaments. Make
sure the radio has adequate ventilation. Finally, and perhaps most
important, before plugging in or powering up the radio, be safe! Make
sure your R390A has a good electrical and RF ground.

The audio output of this receiver is much like most other military
receivers having a 600 ohm impedance. This means, if connected to a
regular 8 ohm loudspeaker, it will sound weak and distorted. The
"local audio," that is, the audio controlled by the "local gain"
control on the front panel appears on pins 6 & 7 on the left hand
terminal block as viewed from the rear of the receiver. The impedance
mismatch when using a 4 or 8 ohm loudspeaker can be overcome easily.
The first solution is to purchase a 600 to 8 ohm AUDIO transformer.
These can be found (at times) at Fair Radio for about $8. An easier
solution is found right at the local Radio Shack. Purchase a 70.7 volt
line transformer (cat. Number 32Ð1031) and connect the primary
terminals marked "C" and "10" to terminals 6 and 7 on the left hand
terminal block located on rear of the R390A. Then, connect the
secondary side of the transformer, terminals "8" and "C" to your 8 or
4 ohm speaker. This will result in an 500 to 8 ohm match which will
give good performance. A closer match may be realized by using a 25
volt line transformer and using the same configuration as above save
for choosing the "1" and "C" taps on the primary side of the
transformer. The secondary wires as above in the 70.7 volt line
transformer.

The antenna connection is even more simple. The radio has been aligned
using the "Balanced" antenna input located on the rear of the
receiver. Turn the receiver around and face it. TBÐ102 will be on your
left and TBÐ103 on the right. The "Balanced" antenna input is located
in the upper middle. Examine the connector and notice it has two holes
for pins located within the connector. Simply tin your antenna wire
and insert it into the right hand pin hole. Insert a wire in the left
hand hole and ground it using one of the screws which hold the antenna
relay unit to the rear panel. The "Unbalanced" antenna input can also
be used but with a decrease of performance unless it was aligned to
that input.

If you wish to use the proper connector, there are several approaches
from which to choose. A combination of a UGÐ971/U and a UGÐ636A will
adapt a BNC connector to the "balanced" antenna input. A UGÐ970/U will
adapt a PLÐ259 to the "balanced" antenna input. A UGÐ636A/U will also
adapt a BNC directly to the "unbalanced" antenna input.

The vacuum tubes originally had black, heat dissipating IERC tube
shields installed on them. According to a study done by Collins Radio,
this increases tube life by up to 53%. If your radio does not have
them or simply has shiny heat shields which have been painted black,
it might be a good idea to pick up IERC shields at a hamfest. The
R390A uses three sizes, short 7 pins, regular 7 pins and regular 9
pins. These have gotten expensive of late as more and more tube
enthusiasts realize their worth.

A couple of other "don'ts" come to mind. To keep the receiver stable,
DON'T, turn on the "ovens" switch located on the back panel of the
receiver. It causes the receiver to steadily drift in normal
temperatures and can also cause the PTO to be irreparably damaged
should the thermostat fail causing the oven to lock "on." Another tip:
if the receiver is going to be left on but not in use, DO NOT use the
"STANDBY" position on the FUNCTION switch. The now unloaded stages
will cause the various voltages in the receiver to rise upwards
perhaps beyond the tolerances of some critical components. This is
caused by the multiplicity error in our sometimes 120v+ line voltage
v/s the 115v in use when the 390A was designed and built. Since it is
normal for the "LOCAL GAIN" control to not completely mute the audio
when turned down fully, it is natural to consider putting the receiver
in "STANDBY." Remember, DON'T. Instead, turn the audio down and also
back off the RF GAIN control to about 11 o'clock and the residual
audio will disappear and no damage will be done to the receiver.

One of the mods I install is a precision replacement pot used to zero
the "CARRIER LEVEL" meter. It is located on the top of the IF chassis
(chassis module behind the "LINE LEVEL" meter). To adjust it, let the
receiver warm up for about and hour then unplug the antenna and tune
the R390A to a dead spot on any band. Remember, the R390A is VERY
sensitive and simply unplugging the antenna is not 100% insurance of
completely removing a signal. Once a dead spot has been located, zero
the "CARRIER LEVEL" meter with the presicion control.

The "IF OUT" connector on the rear of the receiver can provide an IF
signal to the VERY EFFECTIVE, highly recommended, Sherwood SEÐ3
synchronous detector. An SEÐ3 and R390A combination are a "deadly"
combination of classic tube engineering and modern technology. I have
found that using the SEÐ3 MK3D, the operator is able to recover about
30% more useable audio from a given AM signal with more fidelity and
far less distortion than the R390A alone. All of this, without the
shortcomings of todays receivers using "modern," (cheap) engineering
approaches.

Speaking of audio, supurb results can be realized by coupling the
"DIODE LOAD" point on TBÐ103 located on the rear of the receiver to a
HiÐFI amplifier. Simply obtain an audio extension cable with an RCA
plug on one end from Radio Shack. Place a 470K resistor in series with
a 10uf, nonÐpolarized (also available at Radio Shack) capacitor and
connect it to one of the screws holding the jumper across the "DIODE
LOAD" screws on TBÐ103. Do not remove the jumper. Connect the other
end of the capacitor/resistor network to the center conductor of the
RCA cable then ground its shield to the "GND" screw located on TBÐ103
immediately to the right of the "DIODE LOAD" screws. Plug your cable
into the TAPE or AUX jack on your stereo receiver, adjust the tone
controls as appropiate and enjoy.

For EXCELLENT AUDIO, try tuning into the Venezualean Ecos del Torbes
after local sunset on 4980. Open the "BANDWIDTH" to the 8kc position
and enjoy some of the best hollow state audio you will ever hear!!!


Resources for the R390A Owner


Sherwood Engineering

Builders of the SEÐ3 MK3D and other useful items. I have personally
had very satisfactory dealings with Bob Sherwood beginning in 1975
when I bought a modification package for my Drake R4ÐC. While the SEÐ3
MK3D is not effective in receiving SSB, I cannot recommend it highly
enough for achieving top AM performance with the R390A.

Sherwood Engineering 1268 Ogden Street Denver, CO 80210 (303) 722Ð2257
P.O.C.: Bob Sherwood


Hollow State News Compendium

The Hollow State News focuses on service and useability issues on
receivers such as the R390A, Hammarlund SPÐ600 and HQÐ180(A).
Recently, Charles Talbot, K3ICH has offered a bound reprint compendium
of all issues of the HSN. Contact him directly for information and
pricing.

Charles Talbot Ð K3ICH 13192 Pinnacle Lane Leesburg, VA 22075Ð6146


Hollowstate News

HSN $5 for a 4 issue sub. Back issues $1 each and as if 1/1/97, we are
at issue #39. Make checks payable to: Ralph Sanserino.

Ralph Sanserino PO Box 1831 Perris CA 92572Ð1831


R390A Manuals

Original manuals can be purchased from:

National Technical Information Service Technology Administration U.S.
Department of Commerce Springfield, VA 22161

The NTIS Sales Desk is available between 8:30 a.m. and 5:00 p.m.,
Eastern time, Monday through Friday.

Sales Desk: (703) 487Ð4650 Subscriptions: (703) 487Ð4630 TDD (hearing
impaired only): (703) 487Ð4639

Mail Orders Send orders to: NTIS 5285 Port Royal Road Springfield, VA
22161

Fax Orders (703) 321Ð8547

Fax service is available 24 hours a day, 7 days a week. To verify
receipt of your fax, call (703) 487Ð4679, 7:00 a.m. to 5:00 p.m.,
Eastern time, Monday through Friday.


HiÐFi Audio Chassis

Noted Electric Radio Author Bill Kleronomous, KD0HG will modify an
existing R390A audio chassis to provide "hiÐfi" sound backed with
about 5 watts of pushÐpull power. As an added bonus, the 600/8 ohm
audio matching transformer is no longer required. So, if you want to
hear excellent audio from your R390A, consider obtaining a spare audio
chassis and send it to Bill to modify. While not especially attractive
for DX'ing, I can personally attest to the improved audio for the
program listener. Contact Bill for current availability and pricing
at:

Longmont Audio Labs 224 Main Street Lyons, CO 80540 (303) 823Ð6438


Cabinets

Yes, thats right. Cabinets! You can purchase top quality vintageÐtype
metal cabinets which fit the R390A. These are even complete with piano
hinge top covers! The best part is the price, about $125 for the "DCR"
series cabinet as of 1997.

Premier Metal Products Company 381 Canal Place Bronx, NY 10451 (718)
993Ð9200 (East Coast) (909) 829Ð3089 (West Coast)


Collins Collectors Association

While the CCA focuses largely on Collins' contribution to amateur
radio products, membership can be helpful to R390A owners. I recommend
membership in the CCA. Any person who has an interest in Collins Radio
is welcome to join. Annual dues are $15 per year for those living in
the US and $18 for Canada. This includes a membership certificate and
the quarterly newsletter, The Signal.

Mail your remittence in US funds to:

The Collins Collectors Association PO Box 840924 Pembroke Pines, FL
33084Ð0924


Electric Radio

ER publishes a monthly magazine about the size and format of the
current NASWA Journal. It is a very worthwhile publication and focuses
entirely on tube or "hollow state" receivers and transmitters.
Electric Radio is $38 per year mailed first class and $28 for 2nd
class. Canada is $39.

Electric Radio P.O. Box 57 Hesperus, CO 81326


Fair Radio

Fair Radio has been around since 1947 and sells, among other things,
R390A parts and entire subÐchassis. Their prices are, in my opinion, a
little on the high side of reasonable but Fair has always given me
excellent service.

Fair Radio PO Box 1105 Lima, OH 45802 (419) 223Ð2196


Antique Radio Supply

Antique Radio supply caters to the hollow state enthusiast. They have
a large selection of vacuum tubes and other goodies.

Antique Radio Supply 6221 South Maple Street Tempe, AZ (800) 706Ð6789


North American Shortwave Association

For those interested in listening to Shortwave Broadcast or Shortwave
Broadcast DX'ing, NASWA fills the bill. They publish a monthly 60+
page bulletin with program schedules, features, DX listings and other
S.L. material. NASWA is the oldest SWBC focused organization in North
America. A sample bulletin can be obtained for $2 from:

NASWA 45 Wildflower Road Levittown, PA 19057


Hamfest Shopping List

It is never a bad idea to have a few spare parts around for your
R390A. Even though the receiver was designed and built to the highest
quality milÐspec standards using silver plated contacts, all stainless
steel hardware, modular construction and industrial grade tubes, it
can still break. The spare receiver I bought for $50 a few years ago
as well as this stock of replacement tubes has proven invaluable the
few times mine has actually needed repair.

This is the suite of vacuum tubes used in the '390A. It is a good idea
to pick up at least 2 complete suites of tubes while they are still
reasonably priced and even better to have 4. Make a few copies of this
page and take it with you to the next hamfest. Always try and purchase
the industrial tubes. These are the underlined numbers.

R390A Vacuum Tube Suite

Tube Type Quantity Price Each (1996)

6AK6 3 $2 Ð 5

5654 2 $2 Ð 5

12AU6/5814A 2 $2 Ð 8

26Z5W 2 $10 Ð 20

3TF7 1 $20+

6BA6/5749W 6 $2 Ð 5

6C4/6100 3 $2 Ð 5

6DC6 1 $5 Ð 10

OA2 1 $5 Ð 10


Total Tube Count: 26

As of this writing, tubes are not as difficult to find as some of the
handwringers might say. On the other hand, the number of available
tubes is finite so consider building a stock with the goal having at
least 4 complete sets on hand. Also, always try and purchase JAN
tubes. These are found in plain, white boxes, are labeled JAN and also
show the date of mfg on the box. In the case of the 6BA6, 12AU7 and
6C4, try and purchase the 5749, 5814A and 6100 respectively which are
premium tubes with JAN/Industrial specifications.

** NEVER, EVER INSTALL CHINESE OR RUSSIAN TUBES IN AN R390A ! (Unless
there are no more US tubes left on the planet)


About IERC Tube Shields:

The R390A uses 5 different sizes of heat dissipating, black, IERC tube
shields. Installing the correct type and part number shield can
dramatically decrease the operating temperature and in turn, increase
the life of the vacuum tubes. Collins addressed this back in the early
50's in service bulletin #303 which graphically compared the
beneficial performance of various types of tube shields with not using
shields at all.

The proper tube shields can easily identified. They are anodized black
(or deep purple), have an open top with a series of tabs folded over a
thin, octagonal metal tube inserted longways inside the shield. They
are also plainly labeled "IERC." There is a unique model number
stamped on the outside of the shield denoting which size it is
designed to fit. Refer to this number when obtaining the shields.

Below is an inventory with individual quantities of the 5 different
part number IERC tube shields used in the R390A:

IREC Tube Shields for RÐ390A

Part Number Quantity Description

6025ÐB 1 Tall 9 Pin, used for the ballast tube

6020ÐB 9 Medium 9 pin, used on 5814A's and 26Z5W's

5015ÐB 2 Short 7 pin, used on the 5654's

5020ÐB 13 Medium 7 pin, used on 6BA6's, 6C4, 6AK5, etc.

5025ÐB 1 Tall 7 pin, used on the OA2


Black tube shields labled "WPM" my also be found. While I personally
don't feel these are quite as effective as the IERC design, they are
far and away better than the shiny types described below.

Radios which still have shiny tube shields should have them replaced
with the above IERC shields as soon as possible. Even if they have
been painted black on the outside, these shields have no provision to
grip the tube bottle and sink the heat away from it. Also, the bright
inside surfaces of the shield actually reflect the heat back into tube
and on to the dark internal plate structure which could cause the tube
to over dissipate and shorten its service life.


R390A/URR Restoration Summary

For: Owner:

Order Number:FRÐ36Ð039ÐNÐ8Ð0189(E)

Each R390A/URR that I rework has many hours invested in the
electronic, mechanical and cosmetic restoration process. Each receiver
is given a thorough general operational check before the restoration
process begins and any problems or deficiencies corrected. Below is a
brief, general checklist of what was done to this particular receiver.
Other, specific items are addressed on a unit by unit basis according
to need and may not be specifically noted here.

Ð GeneralÐ Electronic & Mechanical

Clean switches and control pots with Caig Laboratories, DeOxit¨ Remove
all subÐchassis assemblies and clean main chassis with water
displacement/lubricant Lubricate front panel switch click stops with
Redline ¨ CVÐ2 synthetic grease Remove all subchassis modular plugs
and clean pins. Apply Caig Laboratories, DeOxit¨ to plug sockets and
reinstall Install 3 wire A/C cord per military procedure Verify proper
fuse value(s) Remove, clean and grease front panel bearingÐthrus for
"Kilocycle Change," "Megacycle Change," "Bandwidth," "Ant Trim," and
"BFO Pitch" controls Test all vacuum tubes and replace as required
Clean all vacuum tubes and apply Caig Laboratories, DeOxit¨ to pins
and reinstall Tighten all tube socket screws


Ð Main Chassis Assy/GeneralÐ Cosmetic

Remove, sand, repaint, reÐwhite and bakeÐfinish all control knobs
Remove, clean, strip to bare metal, fill as required, sand, repaint,
reÐletter and bakeÐfinish front panel using DuPont Centari¨ Acrylic
Enamel (automobile) paint Polish or replace and polish stainless steel
front panel screws Remove and refinish meters Remove, sand reÐpaint
and bakeÐfinish readout bezel. Clean lens.


Ð RF SubÐChassis Assy

Set cam profiles to match PTO electrical "length." Set VeederÐRoot
counter for proper (35kc) end run out Remove all RF and IF slug racks
and clean hardened grease from bearing slides. ReÐapply MobilÐ1¨
synthetic lubricant to bearings and slide surfaces ReÐsolder all
connections in signal path with silverÐsolder Clean and lubricate gear
train with MobilÐ1¨ synthetic gear lube Clean VeederÐRoot counter
readout Clean subÐchassis Clean antenna trimmer and align gear train.
Lubricate helical gear. Set calibrator frequency


Ð P.T.O. SubÐChassis Assy

Remove PTO, disassemble, clean and lubricate with Redline ¨ synthetic
General visual check, test for bad connections Reinstall PTO and set
end points Shim PTO for proper mechanical centering on tuning shaft
Set "Zero Adjust" clutch for center Clean subÐchassis


Ð IF SubÐChassis Assy

Replace CÐ553 with .01ufd 600V Orangedrop capacitor to protect
mechanical filters Replace "Carrier Zero" pot with 10 turn, precision
wireÐwound variable resistor to allow accurate meter setting Grease
"Bandwidth" click stops Tighten all wafer switch stacks Clean
subÐchassis


Ð AF SubÐChassis Assy

General visual check and test for bad connections Clean subÐchassis


Ð Power Supply SubÐChassis Assy

General visual check, test for bad connections Clean subÐchassis


Prior to final Q.C., each radio is operated for a full 3 hours. This
allows the unit to properly heatÐsaturate before a full alignment of:

1st and 2nd IF's RF SubÐchassis assy IF Gain AGC coupling BFO
neutralization Crystal filter neutralization Mechanical filter
impedance matching (where applicable) 1st Crystal Oscillator Carrier
Level meter (will drift with time and is user adjustable) DX Situation
Test


Notes:


R390A Sensitivity Performance Summary

EAC Mfg R390A #905 Order #FRÐ36Ð039ÐNÐ8Ð00189(E)

After completion, each radio is checked for sensitivity and general
performance on significant bands used by the SWBC DX'er and Amateur
Radio Operator. Below is a final postÐrestoration performance summary
for this receiver.

Band Frequency 10db S/N + N Sensitivity (uv) 4kHz filter, AM

120M 2.2 MHz

90M 3.3 MHz

60M 4.8 MHz

49M 6.0 MHz

41M 7.1 MHz

31M 9.6 MHz

25M 11.8 MHz

20M 14.2 MHz

19M 15.2 MHZ



PTO End Point Error:

This R390A/URR Restored and Tested For:


Some Targets to Hear on the R390A

Evaluating the performance of this receiver by listening to the
amateur bands or the BBC is a little like looking across your yard
with a telescope. You don't really find out much more than you already
knew. Here are a few Shortwave Broadcast DX targets to try for. All
are just a bit on the difficult side. The challenge just might
surprise you and open up a whole new hobby segment, Short Wave
Broadcast DX'ing.

All listings are by UTC time:

1130 AUSTRALIA 2.310 MHz VL8T CAAMA Radio. This station along with its
sister on 2.325 broadcast to the Australian Outback. Look for them
between 1100UTC and local sunrise. (Propagation during winter months
only)

1130 Papua New Guinea 4.890 MHz National Broadcasting Commission.
While the transmission is in English spattered with Pigin, this
programming of this station is intended for local consumption. They
sign off weekdays at 1200UTC but are on longer over the weekends.

1228 India 11.585 MHz All India Radio Hear this somewhat easy catch as
it signs on at 1230 UTC. They stick around till 1600 and you can hear
exotic subÐcontinental music. Also try 10.330mHz during the same time
period or 11.620 during local evenings.

2200 Ghana 4.915 MHz Ghana Broadcasting Corp. The later afternoons
yield many stations broadcasting on the 60 meter Tropical Band. This
is one of the strongest and can show as early as 2000 UTC in
midÐwinter. This is the frequency for the Home Service where the
listener can enjoy a sampling of African "High Life" music.

0230 Peru 4.991v MHz Radio Ancash.This station is nearly coÐchannel
with the 350 watt R. Apinte in Suriname. Both are excellent catches.
R. Ancash is a station by which I usually judge the performance of a
completed R390A.

0130 Venezula 4.980 MHz is Ecos del Torbes. A real powerhouse in ECNA,
you can hear plenty of Latin music till their 0400 sign off.

0250 Zambia 4.910 MHz ZNBC. This station signs on at 0300 but runs a
long interval signal, the Call of the Fish Eagle from about 0250. This
is usually followed by great selections of African "HiÐLife" music.

0300 New Zealand 15.115 MHZ Radio New Zealand. While this is a
government station, it runs local commercials and programming.
Interesting listening.


Operating Notes

Because your BFO makes a great AM tuning aid, it has been carefully
set up to help you perfectly tune a station. Ever wonder when a
station is perfectly tuned and in the center of a filter passband?
That is quite important for best audio recovery and lowest distortion.

Your R390A has 4 MilitaryÐgrade Collins Mechanical Filters plus 2
crystal filters in the IF section whose center frequency is 455KC. I
have optimized their center frequency very carefully during alignment.
Additonally, the BFO has been precisely set to zero beat with a 455KC
signal coming through the IF when it is set to "0" or center on the
front panel scale. Here is how to use the BFO as a tuning aid:

A. Make sure that the white marking line on "BFO Pitch" knob lines up
exactly with the "0" mark on its front panel scale.

B. Select the filter you wish to use. C. Turn the BFO on then tune the
main, "Kilocycle Change" control for an exact zero beat with the
carrier of the desired station. Do not adjust the BFO control to
attain zero beat! D. Turn off the BFO and monitor the broadcast.

Using this technique, the desired signal is centered exactly in the IF
passband. You are assured of maximum audio recovery with the lowest
possible distortion.

Remember, this technique is for AM only. SSB, a kluge on the R390A at
best, requires a different procedure.


13 January 1998