Dedicated to True Believers World Wide 
18 September 2012   


What would you like to know about?

Thanks to all who wrote to let us know what topics you'd like to see covered in the Newsletter. Several articles - the kind radiomen like - are being written by MRHS members and will appear in future numbers of the Newsletter.

Topics for future articles will include tone sets used to remotely key the KSM transmitters and the H over 2 transmitting antenna used for frequencies above 8Mc at Bolinas.

As always, your comments and suggestions on all aspects of the Newsletter are most welcome.  Just send an email message to 

Dual Diversity Point-to-Point Receiver R-3


While most of the attention these days is focused on our restoration of ship-to-shore station KPH (now operating under the call KSM) it's worth keeping in mind that the original Marconi long wave transmit and receive stations and the later RCA shortwave transmit and receive stations were not concerned with ships at all.  They were engaged in the business of trans-oceanic point-to-point communications with the cities of the Pacific rim.  This was a truly massive operation that ended in 1973 when the last shortwave circuit - to Tahiti - closed down.
In past numbers of the Newsletter we have documented the restoration of transmitter No. 298 at Bolinas by a highly skilled team of current and former HP engineers.  No. 298 began life as an independent side band point-to-point transmitter.
Now comes Mr. Steve Pazar, a member of the HP transmitter restoration team, to tell us of the companion dual diversity receiver, the R-3.
Steve, please take it away...
While restoring the RCA T-3 transmitter (MHRS newsletter #10), we noticed that a companion receiver was mentioned in the manual. As it turns out the T-3 represents only half of the full story. The other half is the R-3. At this point it is not certain that any R-3 receivers were used at KPH but it is likely that they were. After all, RCA owned and operated this site for several decades. The only hint is an R-3 manual in the archives and a single module in the store room at BL. More research is needed to definitively determine if they were used or not.
Receiver R-3 as shown in the manual.  Note the step and the handle above on the divider between the racks for reaching those top level controls.

Having owned and restored a number of SW and ham receivers over the years, I was curious about the R-3. The following is a brief overview of the details of design and construction of this amazing receiver. This isn't something you're likely to find in anyone's ham shack!


We apologize that the block diagrams are not as easy to read as we would like but they're included for information purposes.


Block diagram 4-2.


Block diagram 4-3

RF Amplifier: 
This receiver utilizes 4 bands (2.8 - 5.0 MC, 5.0 - 9.0 MC, 9.0 - 16.0 MC and 16.0 - 28.0 MC). Each band in each receiver includes 3 tuned RF amplifiers (four tracking permiablity tuned circuits each) a mixer, and a cathode follower buffer. Selecting the band turns on the filaments for the pair of amps needed. 
The HF Oscillator unit provides a signal that is 1 MC higher than the channel frequency to each mixer. AGC from various sources control the gain of the RF amps. A separate antenna input connector is provided for each band and each receiver. There is a single knob for each RF Amplifier. An internal view of one of these shows the lead screw and rack for the tuning slugs. Two of these units are used, one for the two low frequency bands and another for the two high frequency bands. A total of 36 tubes are used in these.
RF amplifier tuning rack.


HF Oscillator: 
This is the common VFO for both receivers, and it is a PLL source. Harmonics from a 1 MC ovenized crystal oscillator (the 6th through the 31st) are used along with a Collins PTO to generate the signal used to derive an output that is 1 MC about the channel frequency. The channel frequency is selected via two front panel knobs. The output of the HF Oscillator is buffered and connected to the mixers in the RF Amplifiers. 14 transistor and 2 tubes used. Its interesting to note there were two versions of this unit, the first using only tubes. 
R-3 HF oscillator.


1 MC IF: 
This unit performs 5 functions; Two, 3 stage 1 MC IF amplifiers, 1 MC to 100 KC IF conversion, 100 KC xtal reference oscillator, dual  channel sideband plus carrier AGC and AGC switching, 16 tubes used.


900/1100 KC Oscillator & AFC: 
This unit provides either a 900 KC or 1100 KC signal to the second converter in the previous unit. This allows selection or upper or lower sideband. A comparative AFC is also included which utilizes the 100 KC reference. AFC is accomplished with a motor driven capacitor. This shifts the 900/1100 KC oscillators to track the incoming signal. A squelch circuit is also included. 12 tubes used.


Carrier Conditioner: 
This unit performs three functions; It extracts the 100 KC carrier from the 100 KC IF to provide carrier AGC, provides the voltage for squelching the the AFC function in the previous unit under weak signal conditions and and provides a constant level carrier for use in the demodulator and AFC circuits. 11 tubes used.


Roofing and Sideband Filter:
This is a fully transitorized unit. Three 100 KC IF band pass filters are used per receiver. Four bandwidths are available (12, 9, 6.2 and 4 KC). Upper and lower sideband filter (these are seperate) are also included. It is unclear from the manual if these are Collins mechanical or crystal lattice filters. 14 transistors used.


This is another fully transistorized unit that contains the demodulators and audio amplifiers for both receivers. Two are required for ISB operation. The demodulator consists of two balanced demodulators, one per receiver. The reference signal is selectable between the 100 KC reference oscillator and the  constant level carrier output from the Carrier Conditioner unit. Two low level audio amps are also on board. 14 transistors used.


Diversity Phone Combiner: 
This unit takes the audio from each receiver and using 3 filters per channel breaks it down into 3 bands (high, medium and low). 6 filter all together. The audio signal that passes through the low frequency filters is rectified and compared. The resultant analog signal (not digital) changes the gain on two post filter amps, favoring the channel with the largest signal. The same process occurs for the high and medium audio frequencies. The output from all 6 amps are combined giving a single audio channel. 41 transistors.


There are also a number of optional modules available for processing signals; Frequency Shift Tone Receiver, Dual Diversity Comparator (different than the Diversity Phone Combiner), and a CW tone keyer. There is also a power supply unit and control panel for the entire receiver. 
Construction of the modules is very similar to the T-3 with all chassis and panels made out of heavy gauge aluminum. One nice feature of the R-3 is not only do the modules slide out for servicing, but the chassis can tilt on their slides for easy access.


As you can see, this is a very capable and flexable receiver system that incorporated many new (for the late 1950's) technologies. 
I would like to thank Sheldon Daitch for sending a copy of his manual of the RCA R-3 which was the source for this article. He also provided the picture of R-3's in use at the VOA site where he was an engineer. According to Sheldon, the VOA used a lot of these receiver in their facilities; 8 at Greenville, NC, as many as 25 at Kavala, 10 at Rhodes and Banguio and unknown number at Bangkok, Munich, Tangiers, Sri Lanka and Liberia.
R-3 receivers at VOA Greenville, NC site.
RF amplifier data plate.
If anyone has any additional information about the R-3, where it was used or if any still exist, I would certainly like to hear from you. A long term goal of mine is to try to collect enough modules to cobble together as much of an R-3 as possible, and building what cannot be found if needed. So far only have one of the RF Amplifier modules.


One of the operating positions for Steve's amateur station, W6SSP.

Make a Donation

As Steve mentioned above we have virtually nothing of the point-to-point service to restore and present as a way to document that important phase of radio history.  Every once in a while we hear of receiver hidden away in a barn and immediately jump into our vehicles to check it out.  It's always a false alarm - except for an AT&T point-to-point receiver (not a R-3) located near the editor's home. We've been hoping for years to give this artifact a loving home.


With guys like Steve on the case looking for any fragments we can find to complete the whole we have reason to hope that a R-3 may live again.

To all those who have sent along a contribution to The Cause we offer a heartfelt thanks.  Your support is tremendously appreciated.

If you're a True Believer and can make a contribution to The Cause it will be most appreciated.  And remember, we're all volunteers so 100% of your contribution goes directly to purchase the items needed to keep the transmitters and receivers working and the antennas in the air.  




Radio Archaeology - Part Two of a Series 
Mystery Transmitter  
Faithful readers of these pages will recall that in Newsletter No. 12 (incorrectly identified as No. 11) we reported on an expedition we made with the hope of locating the early home of KPH at Hillcrest above Daly City, south of San Francisco.  We were successful and had the thrill of standing on the hallowed ground where the station formerly stood.
Now we come with a challenge for all those fans of heavy iron.  You say you know your vintage transmitters?  Well, we ask for your help to identify this relic.
We are unable to disclose its location.  All we can say is that it's located in a historic building somewhere in California.
Front view.
The only data plate on the unit.
Final amplifier, rear view.
Can you help with an identification?  Is his badly mistreated relic worth saving?  We await the replies of True Believers.  Send your best guess to 
Vintage Cars Visit Vintage Radio Station
Last weekend we were honored by a visit from members of the Acorn A's Model A ford club. Organized by Mr. Mike Cozad, these folks are True Believers in their own right and brought three of their wonderfully restored vintage vehicles to both the transmit and receive sites.


Model As before Building 2A at the RCA transmitter site in Bolinas.
We've had lots of other groups visit us.  Why not organize a visit for your group?  We'll give you the "A" tour of both sites (or just one if that works better for you) so you can see all of everything.
Just contact us to make arrangements. 
Operations Report


Mike Payne and Rick Wahl of the Operations Department apparently have great depths of energy upon which they can draw.  Or maybe it's just dedication to The Cause.  Either way they have been returning KSM to almost like it was in the glory days of KPH with multiple positions banging away and stations being worked left and right.  


First it was the expansion of operating hours to include Sunday.  Now as a result of their zeal KSM and K6KPH are on the air Wednesday evenings (Pacific time) as well.


The first day of Wednesday operations was a great success for both stations with ships and land stations worked and many True Believers writing to report the signals they heard.  And these include reports from such disparate points as Switzerland and Australia!


Get your earphones on for this Wednesday.  See the times at the conclusion of this report.


Mr. and Mrs. America and all the ships at sea... let's go to press with the operations report for KSM and K6KPH...
Wednesday Sept 12th/13thGMT

Position 1




0225  NWVC  (12)  USS LST 32H Ohio River SW Indiana

0315  WDC5383  (6)  East Coast (VA?)




0233  AL7N  (14)  AK

0240  WB6JV  (14)  CA

0244  W1ZMB  (14)  NY

0250  AG4HR  (14)  NC

0353  NK4E  (14)  FL

0407  W7IZE  (14)  OR

0427  N9NE  (3.5)  No QTH

0505  K2GTC  (7)  NY

0509  K6GVG  (7)  Newport Beach

0525  YB2HM  (21) QSB to nil, no QTH

0527  JA2HT  (21)  JA

0533  V8HSS  (21)  QSB to nil, no QTH

0535  DV5PO  (21)  QSB to nil, no QTH

0544  W4LNI  (7)  FL


Position 4




0158  K6LQI  (7)  NV

0200  KA6JLT  (7)  NV

0210  VE7LIQV (3.5) No QTH

0215  KE7JOG  (3.5)  WA

0259  WS0L  (3.5)  CO

0311  WB2LQF  (14)  NY

0327  KC7YE/M  (7)  WA

0348  W6AWO  (3.5)  Guess who

0412  W7ASA  (7)  VA

0448  W0UFC  (7)  CA  KSM sig report

0519  WB6UBK  (7)  CA

0540  W4LNI  (14)  FL

0547  OH1FQ  (14)  TURKEY


Saturday  Sept 15th


Position 1




1905  KKUI  (12)  FL




1943  G0WKL  (14)  UK

1945  W4LNI  (14)  FL

1955  G0WKL  (14)  UK

2005  NJ6VT  (14)  USS Pampanito  ARC  CA

2007  VE6LLV  (14)  CAN

2025  VE7KBN/P  (14)  BC

2037  K7HV  (14)  WA QRP 3watts

2050  N0EF  (14)  MT

2210  JH6DVR (14)  JA  Unsure of c/s

2223  N0AX  (21)  MO

2233  N5XE  (21)  MO

2235  7M1NFC  (21)  JA

2238  W4LNI  (21)  FL 

2245  KC0URL  (21)  MN

2300  DS2LET  (21)  QSB to nil  unsure of c/s


Position 4




1925  AL7N  (14)  AK QTC 2 for NTS

1955  LU6YCB  (21)  Patagonia, Argentina

2058  W6VJJ  (7)  CA


Position 6




2200  W7AEP  (7)  OR

2205  VE6LLV  (7)  CAN

2208  K7UK  (7)  WA

2216  AA6GI  (7)  CA


Sunday Sept 16th






Position 1




1950  W8IM  (14)  FL  KSM sig report

1952  K6JJR  (14)  CA

2008  K8FZY  (21)  WA

2015  W6RA  (7)  OR

2017  W6AWO  (7)  Guess who

2038  K3PG  (21)  MD

2039  WD0BC  (21)  MO

2050  VE6LLV  (7)  CAN

2113  KM7SM  (14)  ID

2115  AL7N  (14)  AK  Informal TFC fm K6KPH

2140  W8IM  (14)  FL  QTC

2205  JJ1RZG  (21)  JA

2211  W9FAM  (21)  IN

2224  W5APS  (21)  TX

2230  WB4ZX  (21)  FL

2238  JF1HTW  (21)  JA

2248  JA3YKV  (21)  JA

2255  JA2FGE  (21)  JA






Grunches of visitors (I lost count)...RD swamped...may have been unable to remember his name though I didn't ask him.  RK makes repairs to MF Filter Box Relays out in the antenna field.  MP finally sighted missing cow in the case of "The Phantom Cow" if only for a few moments as it retreated into the bushes as soon as it was sighted.  (Re: the week before...only cow patties were sited near the entrance steps to the station.)  And a few hours later that same day RK also sighted said cow...only for a few moments, too.  RD wanted to know if it had been in the station.  I replied with a negative.  TFC List and WX sent out as normal.




Only five visitors today.  TFC and WX sent out as normal, tho at first MP couldn't find the TFC List on the computer to download file...UHF'd RD who saved the day instructing MP on the basics of how to find computer files.  No cow sighted.  Of note was the very heavy QRM on 14mhz...contesters.  I heard stations calling but was unable to answer due to QRM5/ S20+ most of the day so I spent much of the time split between 7 and 21mhz.


QRX:  Wednesday night, Sept 19th, 7pm to 11pm local time.  MP and FW on watch.


As always, if I have listed your c/s incorrectly or neglected to list your c/s please let me know and I will make the correction in a following newsletter.  73s from zut central.  MP



VY 73, 

MRHS Operating Department 

Until next week we wish you fair winds and following seas.

VY 73,


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