Dedicated to True Believers World Wide 
12 February 2013

  • Transmitter 298 Lives!   
  • K6KPH is Everyone's Sweetheart 
  • Operations Report 



Transmitter 298 Lives!


Faithful readers of these pages will doubtless recall our earlier reports on the astounding work being done on "H"set transmitter S/N 298 at Bolinas.  As those reports described a team of dedicated and talented current and former HP engineers took up the challenge to restore this transmitter to operational status more than a year ago.     


The RF section of No. 298 in an early stage of restoration


While there are several "H"sets at Bolinas none had been restored.  That's because of the dual intimidating facts that the are a> the most complex transmitters on site, having independent sideband capability, and b> all examples were seriously degraded by rust and corrosion, the result of sitting unused in an essentially marine environment for more than a decade.


See Newsletter No. 10 for the initial report on this transmitter including hard to believe before and after photos showing the level of workmanship being applied to this restoration.  Then read the updates in Newsletter No. 11 and Newsletter No. 14.


We are happy to report that on Saturday  9 February transmitter 298 put 5kW of power into a H over 2 antenna on the KSM 22Mc frequency.  There is still work to do before No. 298 enters full service but we thought you's want to hear this news.


Now comes Mr. Bob Dildine of the H set crew with his narration of Saturday's events:




Bob, Larry, Greg, and Kurk went out to Bolinas February 9. Kurk brought out the spare screen supply he restored and Bob brought out the spare linear amp he checked out.    


The open wire feeders are followed through the H frames out to the antenna by a member of the H set crew 


We walked the transmission line for our antenna all the way out to the antenna and it looked good except for one spot where a jumper around a cross-arm has been mashed down on the cross-arm, probably by a heavy bird.    


Note the unhappy result of heavy bird sitting


We secured all the exciter units into the H-set's rack, but found that some of the quarter-turn fasteners that secure the front panels to the shields are broken. Larry will look into what can be done to repair them, but all front panels are secured to the rack frame now. Unfortunately, that didn't seem to stabilize the fluctuations in the screen current and that remains a mystery.  


We connected the H-set to its antenna and drove it with a synthesizer set for KSM's 22Mc frequency. The tuning was somewhat different than for the dummy load and we got significantly more antenna current which suggests the antenna impedance as transformed by the transmission line is lower than 600 ohms.  


When we keyed the transmitter, it has a raspy note that sounded like 120 Hz modulation. Earlier tests several months ago showed the H-set to have a nice clean tone. After several experiments, we found the raspy note is the same whether it's driven by the synthesizer or its internal TCXO. We also found that the tone is pure coming out of the exciter and also coming out of the 4CX250 drivers. But when the finals are activated, the note becomes raspy.   


1959 RCA H-Set Restoration at Bolinas #3
Video: Steve contacts the receive site for a signal report 

Line-related modulation clearly shows up on an oscilloscope connected to the transmitter's output. We couldn't track it down but more experiments will be done next time. The screen supply or final bias supply are the suspects at this time. Steve H found a dual RF ammeter assembly that we will install on the H-set antenna output next time out.




As you can imagine, it was a very exciting day.  The moment when we push  the "money button" on No. 298 to put it into regular service can't be far away.  As always, True Believers are welcome to visit with us at the transmit and receive sites.  If you have an interest in being there on the day when No. 298 is officially returned to service please let us know by writing to [email protected].  We'll do our best to give you fair warning of the date and time.


If you've been following these reports of our activities you know that we're all volunteers.  And that includes the H set crew who not only lend their skills and pay for parts but also  make a 100 mile round trip from their home base every time they come to Bolinas.


Of course they do it happily, as we all do.  In truth we consider ourselves to be the luckiest radio squirrels there are.  But you know... a little help from our fellow True Believers would be a great help. 



Make a Donation    
Are you in a position to help The Cause with a donation?  Even the smallest amount helps.  And it lets us know that the project means a lot to other folks, not just to ourselves. 





K6KPH is Everyone's Sweetheart


For the second year in a row the MRHS collaborated with community radio station KWMR in Point Reyes Station in the Sweethearts of the Radio musical fundraising event.

Click on the banner to visit KWMR's Web site and listen on line

MRHS Chief Operator Richard Dillman set up an operating position in the lobby of the Dance Palace while talented and attractive Radiogram Girls circulated through the audience with clip boards and radiogram blanks inviting the attendees to send a radiogram to their sweetie.


The remote setup consisted of (L-R) National HRO-5A receiver, remote control console and RCA AR-88LF with radio room clock above.  The console allows the remote keying of the transmitters in Bolinas. 

The event was a big hit and so were the radiograms.  The Radiogram Girls eventually delivered more than thirty messages to the operating position, giving Dillman new respect for the men and women who 80+ radiograms in an eight hour shift.   

Sadly we don't have photos of the 2013 Radiogram Girls but this snap of Sally Phillips and Mia Johnson from 2012 will give you the idea.  This year Mia was assisted by Katherine Williams and Katie Eberle.  

Originating radiograms is great but it's all for naught unless there's someone to take your traffic!  Thus we have to give special thanks for Ms. Kate Hutton who made the facilities of K6HTN available for a large wedge of messages, our very own Mike Payne who hurried home from his duties at KSM to put station N6BBF on the air for immediate telephone delivery of messages and Morse code champ James Johnston of K6APW who accepted several messages for onward relay.  



Operations Report


KSM Phone: +1 415-990-9646


KSM email: [email protected]


The details are in Mike's report below.  But first let's review our operating hours. 


Operating Hours -  

Here are the current operating hours for both KSM and K6KPH two way operations.  KSM press and weather broadcasts begin at 1000pst (1800gmt).

Saturday - 1200 - 1600pst, 2000 - 0000gmt

Sunday - 1200 - 1600, 2000 - 0000gmt (No KSM RTTY)

Wednesday - 1900 - 2300, 0300 - 0700gmt (No KSM RTTY)

Mr. and Mrs. America and all the ships at sea... let's go to press with Mike Payne's operations report for KSM and K6KPH...

Please follow the link below for recent scanned KSM and K6KPH logs.

As always, Mike says:


Please advise any c/s or data errors in this weeks report and I will attempt to correct same.


For the list of stations worked, go >>==> HERE <==<<


73 fm ZUT central, MP

MRHS Operating Department 

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These are high quality items you'll use and enjoy for a long time.  And every purchase you make helps to support the MRHS.

Click on the image below or on the link below that to go to the MRHS True Believers on line store.



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

VY 73,

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