7 August 2012

Visit the MRHS Web site

MRHS Web Site 



One of the best things about the MRHS is the people who show up, see what we're doing, and want to be a part it.  Even better, everyone seems to find a project they find challenging and fun that also contributes to the overall program. 

Some time ago a group of current and former HP engineers paid a visit, looked around and started working on some of the jobs that needed doing - of which there are no end.  But they wanted something more.  They made the breathtaking commitment to restore a 1950s vintage RCA "H Set", the most complex model transmitter at the Bolinas transmitting station... and in the worst condition.   

Maybe they didn't fully realize what they had taken on.  But pretty soon it was too late.  They had become True Believers and the work they did is nothing short of astonishing - as you will see in the photos below.

At this point we turn the narrative over to Greg Farrell of the "H Set Team".  As you'll see from his fulsome prose, he fully understands the drama of the project and the importance it has in the preservation of our maritime radio heritage.

The Saga of Bolinas RCA H-set Transmitter #298



The T-3 "H Set" as shown in the RCA technical specifications manual 


It was a glorious May 1959 at RCA Bolinas. Another 20kw Independent Sideband T-3 Transmitter had just been delivered by Santini Brothers. Within 3 days, she had successfully sent RF into a dummy load during initial power-on testing. #298 was destined to be the primary point to point circuit between the Bolinas transmitting station and the island of Guam. There provided faithful service to her customers and to the Corporation for 33 years.  In her later years, after the point to point service was discontinued, #298 was modified CW service and made the KPH signal stand tall around the world on 13.002Mc.


The Independent sideband transmitters were designed for near continuous, long-range transoceanic and transcontinental communication on frequencies ranging from 4 Mc to 30 Mc. They could operate in single-sideband, double-sideband or independent-sideband mode. The carrier in any mode could be operated from full carrier to no carrier. The newly developed independent-sideband mode allowed for intelligence to be transmitted on both upper and lower sidebands at the same time, to a receiver such as the RCA model SSB R-3, at the other end in Guam. She was truly an engineering marvel of commercial radio communication of her time.


For 33 years she served, and then sometime in 1993 or early 1994 she was silenced forever. For nearly two decades she sat amongst her now silent H-set brothers and sisters in the south-east corner of Building 2A. Day in and day out, wisps of cool moist and salt laden air from the Bolinas headlands invaded her being, finding every open pore, every crack, every bolt, anywhere RF had lingered to attract salts forever building from the air passing through, so necessary for cooling. The now moist salts began eating away at her metal and electronics, making her incapable to ever produce RF signals again.  Or so some lesser mortals thought... 


In January 2011, a group of MRHS volunteers accepted the challenge of restoring #298 to operational status. Due to her condition, a 100% dis-assembly of the entire RF-Power Amp assembly had to be undertaken, as well as complete restoration of nearly everything else, both mechanical and electrical. This was to be no easy task, as nearly every bolt or screw had become corroded and frozen in place. 6/32 screws snapped off heads at the least amount of torque.


Testing and work continues to this very day. Once again #298 is producing RF into a dummy load, exactly has she had done back on May 21, 1959. Problems, yes! But #298 had seen these before, just as she had experienced back in 1959 when she was first powered up (we have the engineer's notes that attest to this!).


Recently for example, the low pressure blower motor had to be replaced; and PA Plate idle current (key up) is still too high at 1.5 amps. Radio engineering experts, even former H-set techs such as Warren "TR" Reese, last transmitter engineer at KPH Bolinas, all long since retired, have been called upon by Transmitter Supervisor Steve Hawes, to share any knowledge they might have about the idle current and other issues faced by our team.   Steve Pazar and Bob Dildine have taken the lead in our own H-set team, to resolve these issues, along with expert help from Tom Harris and Andy McClean to replace the failed Peerless motor, with a Reliance motor bought by RCA back in 1992.


Truly, everyone in the H-set team deserves a heap of credit for the work they have done over the last year and half, often taking on tasks which had no precedence to resolve. Literally hundreds and hundreds of volunteer hours have gone towards this project.


The IPA deck with two 4CX250Bs as found.  Would you have the heart to take this on? 


The rebuilt IPA deck with the RF power amp deck above.  Each of the 4CX5000 sockets in the RF deck had to be completely dis-assembeled and rebuilt from scratch - just one small part of the total restoration. 


The RF power amp deck as found.  


Two 4CX5000s stand proudly in the RF power amp deck, shown in the final stages of re-assembly in the control room at Bolinas 


Steve Pazar keeps a careful eye on the meters as he brings the transmitter back to life for the first time in decades in a pre-service test. 


The H-Set Team consists of:


Steve Pazar - W6SSP: project engineering lead, PA 4CX5000 sockets, screen by-pass caps, HV DC power supplies, meters and more    

Stan Jaffe - WA6DHM: hardware extraction and PA Assembly removal and re-installation and more

Larry Nutting - K7KSW: Counters, tank circuit tuner, rack signal sources, VU meter, PA unit heater and more    

Kurk Radford - K6RAD: DC power supplies in the rack, cabinet blower and more

Bob Dildine - W6SFH: Main PA assembly  and driver deck, driver plate induction tuner and more    

Andy McClean : Motors, blowers, air filtration and more

Tom Harris -  Pears Repairs:  Motors, blowers, meters, receivers for the receive site, and much more     


Greg Farrell - K6SRO: Power amp sockets, driver plate tuning air capacitors, sheet metal, PA unit heater, project photographer, documentation and logistics and more

John Felton - KE5RI: PA plate transformer heater and more


We'll continue to keep you all posted as we near that glorious day when #298 is once again transmitting RF into the ether, currently expected to be on the 15 meter band (K6KPH) for MRHS special events.  And of course we will let you know when we officially push the "money button" to return #298 to the air! 


Make a Donation

We know not everyone is able to undertake a project like the restoration of H Set 298 or is close enough to be able to participate directly in MRHS projects.  But even if you can't volunteer you can help assure that projects like this wonderful restoration can continue.

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.  






This is a little obscure even for this forum.  But the MRHS has two Model 28 Teletypes in service at the receive site.  The ASR is used to copy the Baudot RTTY transmissions from Bolinas.  The KSR is one end of the land line TTY order wire to the transmit site where a Model 15 is used.  We believe this to be the last land line TTY link in service but we'd love to know of any others.


We have paper winders on both TTYs and we recently became aware of the accessory known as the copy display rack.  This is a wire device that fits atop the paper winder over which the TTY paper travels on its way to the winder so the copy can be easily read.  Inquiries posted on the Greenkeys list and with TTY parts suppliers produced nothing.


Then, last weekend, whilst rummaging through some boxes at the receive site, two copy display rack were discovered!  We had 'em all along!  They were supplied with one of the paper winders but went unrecognized at the time.  So now we have copy display racks for both 28s and we wanted to share our joy.



Copy display rack installed on Model 28ASR at the receive site. 


Now... here's a quiz for the true Teletype aficionados out there.  What is incorrect about the installation of the copy display rack shown above?  Winning entries will an honorable mention in the next Newsletter.  






NOTE: K6KPH will be unavailable on Saturday 11 August.  KSM will broadcast extended press and weather on our CW and RTTY channels but no operators will be available to answer calls from ships.  We truly regret this inconvenience. 


Mr. and Mrs. America and all the ships at sea... let's go to press with the KSM and K6KPH report for report for Saturday 4 August 2012...

It was a bit of a slow day for K6KPH due to stations wall to wall across the bands participating in a contest.  Is it our imagination or is there a contest every weekend?  Since K6KPH uses the fixed frequency transmitters of KPH throttled back to 1.5kW TPO we had to sit and wait for a lull or answer a calling station who could make it through the din.

BUT... There was a bit of a mystery for KSM.  Here's the story:

Ops Rick Wahl (FW) (ex-KPH, ex-NMC) and Richard Dillman (RD) were just setting up at about 1905GMT when a ship was heard calling on 12Mc.  Richard didn't have his keys plugged in yet so Rick took the call... but wait!  There were two ships calling.  Great!  Just like the old days!

But hold on a minute... We were clearly hearing two different transmitters keyed by two different operators... but both were identifying as KKUI, SS AMERICAN VICTORY!  Rick sent DE on the KSM 12Mc transmitting frequency and the weaker of the two immediately answered.  But Rick couldn't break the stronger signal.  For some reason, maybe based on his KPH experience, Rick decided to answer on the KSM 16Mc frequency... and KKUI No. 2 replied!

We await an explanation for this curious event!

Here are the meager stats for Saturday:

Position 4 K6KPH (FW)

1944 N0FMF (7)
2004 KI2F/7(7)
2022 K6ETM (21) KSM REPORT
2139 W9CZ
2225 W7DFO

Position 4 K6KPH (FW)

1905 KKUI 1 (12)
1909 KKI1 2 (12/16)

But wait, there's more!

We had shut down the transmitters at Bolinas and were preparing to head out the door, but the receivers were still on.  RD heard someone repeatedly calling K6KPH on 7Mc.  So the 7Mc transmitter was turned back on (Transmitter Supervisor Hawes in Bolinas probably wondered "what are those guys *doing* up there?"), contact was made with the calling station and RD got to appear on the scoreboard:

Position 1 K6KPH (RD)

0003 W2RS (7)

It should be noted that Bill Ruck (RK) of the MRHS Maintenance Department was Out Standing in his Field (the antenna field) working on the remote controlled filters for the MF antenna.  Not only did he effect a repair, he fabricated a test jig for easier testing of the filter relays on the bench and began a the modification of a box to house the filters to replace the one that has just about dissolved in rust.  Thanks Bill!

Bill Ruck at work on the MF antenna filters. 

We still have openings for volunteer Morse operators at KSM, K6KPH or both.  Why not step up and exercise your skills at a real coast station?  If this sounds good to you send an email to [email protected] .

NOTE: KSM and K6KPH will be active on Saturdays only until further notice.


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

VY 73,



Have you had quite enough of this impossibly dull and boring radio drivel?  Want to unsubscribe?  Sure!  Just use the "unsubscribe" link below....