o BIG NEWS!
Transmtter 298 Speaks!
o Night of Nights 2013 - More Details Emerge
o Maintenance Report - A Tale of LED Conversions and Christmas Trees
o Fantastic Donation to the MRHS - Video!
o MRHS Tries Twitter - Worth the Effort?
o Archivists Corner - Historic RCA Guest Book
o Operations Report
> BIG NEWS! Transmitter 298 Speaks!
|Amps of vintage H set RF surge into the open wire feed lines on Saturday|
Faithful Newsletter readers will have followed the dramatic chronicle of the restoration of RCA T-3 "H set" transmitter 298 as documented in Newsletters No. 10
, No. 11
, No. 28
, No. 30
and No. 37
If you don't have time to go back and read them all now, at least take a look at No. 10
. The photos there will show you what the H Set Crew faced when they decided to take on this titanic project. The contrast between the corroded hulk they began with and proud, sleek and polished transmitter that 298 has become is nothing less than startling.
On Saturday 29 June 298 announced itself on the air for the first time in decades with a pure, crisp signal on the KSM 22Mc channel.
Now comes Mr. Bob Dildine with a detailed report of that event:
It was another productive Saturday for the Santa Rosa crew on June 29.
Bob, Steve, Kurk, Greg, and Larry went out to work on the RCA SSB-T3 Transmitter (the H-set) and its associated antenna. Bob and Steve started out by measuring antenna 22557 coming into the building on the north side with a portable vector network analyzer (VNA) loaned to us for the weekend by Agilent. Since the antenna is fed with 600 ohm balanced transmission line, we used a DX Engineering balun to convert the VNA's 50 ohm coax measurement environment to 600 ohms balanced. The VNA was calibrated with 600 ohm standards after the balun.
|Steve and Bob consult the Aligent VNA|
At our assigned frequency of 22.4458 MHz the SWR was 2.3:1. The SWR plot is attached. We may try to do a better job of matching the antenna to the line in the future.
|VSWR plot of H set antenna|
Kurk, Larry, and Greg then proceeded to move one of the unused transmission lines that run across the building to a position just behind the H-set. That was no easy task as it involved working with #10 copper-clad steel wire while perched at the top of a tall ladder (and wearing a safety harness tied off to the building's steel frame) in a building heated by the summer sun and half a dozen or so high power transmitters. They connected one end of the line to antenna 22557 and the other end to the H-set.
|South end of feed line destined for the H set is disconnected|
Meanwhile, Steve P., Steve H., Bob, and Nick from the tree service walked out in the antenna field to inspect antennas. We found major damage to antenna 22395 which we had tried to load with the H-set on 15 June. It's just a tangle of wire hanging from its support poles and will require major effort to re-erect it. We also found numerous ticks in the field, but fortunately we got them off before any were able to attach.
After lunch we fired up the H-set into the newly connected antenna. The antenna loaded up nicely with about 3.6 amps RF current. The current in both sides of the balanced line was nicely balanced (see the attached picture - the ammeters are from one of the PW-15's from KFS "Marsh" transmitter site in Palo Alto). Since the SWR is 2.3, it's impossible to estimate the actual antenna impedance, so the actual output power can't be measured accurately. But DC input power was about 6.7 kW (1.46 amps plate current at 4600 volts). Assuming 70% which is high for a linear amplifier, this yields about 4,670 watts output, well below our authorized 5 kW.
After all control settings and meter readings were logged, the transmitter was switched to the KSM key line to carry KSM traffic on 22 Mc for the first time since its restoration. The transmitter ran for two hours with no problems. Several reports from listeners have already been received with complements on the tone and keying.
We plan to have the restored H-set on the air for Night of Nights on 12 July.
The H Set Crew has dedicated more than 3000 hours of volunteer time spread over almost three years to the restoration of this magnificent transmitter. They're all volunteers of course, just as we all are. So you have to ask the question: why would anyone dedicate so much time and expend so much effort on a project like this? Maybe the answer isn't that difficult. They're all modest guys - like the guys with the real skills always are. But now they can stand back, arms folded, look at their work and think "I helped with that - and it's the only one like it in the world." Add the fact that the result of their handiwork will be a signal heard literally around the world and the answer starts to come into focus.
The H Set Crew support The Cause with their skill, knowledge and pocketbooks when parts need to be purchased.
We know that if they could, many Newsletter readers would join us of a Saturday to pitch in. If you can't manage that maybe you can help financially. It's easy. Just click on the yellow button!
Help us keep the flame alive. Support the MRHS! Long live transmitter 298!
> Night of Nights 2013 - More Details Emerge
Night of Nights 2013. You don't want to miss this one. It's on 12 July of course, just as it is every year. That's the anniversary of what was thought to be the last commercial Morse message. It's a Friday this year. And you're invited - both on the air and in person.
Check it out: Historic stations KPH and KFS will be on the air along with KSM of the MRHS. Transmitter 298 will be on the air for its first Night of Nights along with the 1950s vintage RCA K and L sets, the 1942 Press Wireless PW15 and pretty much every other transmitter in the joint. K6KPH will be on the air as well, listening for signal reports from True Believers.
We hope and expect that other historic coast stations will join us on the air as well. See below.
If you can join us in person, here are the details:
Location: RCA receive site, 17400 Sir Francis Drake Blvd., Point Reyes National Seashore.
Click HERE for the location via Google Maps
Parking: Please park in the lot to the left of the entry road
Time: Doors open at 3:00pm pdt. First transmission at 5:01pdt. Doors close about 9:00pm pdt
Food: Light refreshments form Perry's Deli will be served.
Tours: Given. Including visits to the Bolinas transmitter site by special arrangement
You'll want to be properly dressed if you visit us so why not score a MRHS hat or T shirt? See our Merchandise list below.
Here's a frequency list - still preliminary.
22445.8 <==<< H set - see above
All stations will listen for calls from ships on 500 and ITU channel 3 HF:
Note: The crack MRHS Transmitter Department reports that every operational antenna will be in use for N of N. At the moment one of the 12Mc antennas and one of the 22Mc antennas are down and may not be repaired in time for N of N. If any more fail the above frequency arrangement may have to change.
In past years stations WLO and KLB od Shipcom LLC have joined us on the air. At press time we have not received confirmation that these stations will be active again this year. But these frequencies were in use for N of N 2012:
Teaser: We can't yet release details since this hasn't been officially confirmed. But there's a very sporting chance that additional stations will be on the air for N of N. As soon as we know for sure we'll send out an extra issue of the Newsletter.
The amateur station of the MRHS will be guarding its usual frequencies (above) for N of N. If you'll be visiting with us and would like to operate K6KPH bring your key and 'phones or use ours. No license required so if you're an ex-commercial op here's your chance to get on the air again.
> Maintenance Report - A Tale of LED Conversions and Christmas Trees
Radioman Ruck of the MRHS Maintenance Department has been at it again. You just can't keep this guy away from a soldering iron and a screwdriver. That works out pretty well for us of course because the number of maintenance projects awaiting his tender attentions count up to a number approaching the infinite.
When we last left Bill he was going on at great length about the rebuilding of the MF filter relay box and the antenna selection switches at the operating positions. Let's listen now as we hear Bill say...
It now is the time when the Operations Department wanted the keying lines changed before NON, July 12th, so Saturday June 22nd was "D Day".
I got up promptly and drove directly to RS so that the dirty deed could be done before operations started at 12 Noon.
First, I cut off the 15 conductor cable at the multiple panel at the top of the rack. Then I plugged in a pre-made cable with a mini Blue Ribbon connector to the 7th jack on the multiple panel and landed those wires on the "KPH KEYING" barrier strip. I cut to length the 15 conductor cable from the Christmas tree terminal strip that had run up to the multiple panel and landed those wires on the "TONE SET" barrier strips.
By that time Chief Operator Dillman
arrived at RS and we tested the connections to the tone sets. All worked as designed.
We then conferred over the relationship between the keying lines and the tones sets (and ultimately the transmitters that they control). Chief Operator Dillman
determined that we'd keep the same arrangement for KSM transmitters as before on the KPH keying control panels. Appropriate cross-connect jumpers were made between the KPH KEYING barrier strip and the TONE SET barrier strips. Those were tested and all KSM transmitter keying lines were ready for operations about 15 minutes before noon. No impact to revenue operations.
There were three extra wires in the 15 conductor cable and those were landed on the Christmas tree barrier strip for tone set positions D3, D4 and E1. In my youth I spent a lot of time soldering Christmas tree terminal strips so I knew how to do this to "Western Electric standards".
|Rear of the tone set rack. Christmas trees to the left, new keying line barrier strips and jumpers to the right.|
Then we conferred about the relationship between the WCC keying panel and K6KPH frequencies. Part of the design for the WCC panels was that there are two wheel busses: one buss 3, 5, 7, and 9 and the second buss 2, 4 6, 8, 10. (WCC keying line #1 was dedicated to MF and no wheel is used on MF.) Since we now have 5 K6KPH frequencies we decided to put all of them on keying lines used by the second wheel buss. Again, appropriate cross-connect jumpers were made between the WCC KEYING barrier strips and the TONE SET barrier strips. All tested good.
|WCC transmitter control panel (black), now with K6KPH transmitter control switches|
Finally, the one "wild card" tone set was discussed. This one is special to key the KSM PW15 transmitter on 12,993 kc/s. We decided to put that on KPH panel line #3. Appropriate cross-connect jumper was made. I then made up and installed new labels for the panels for all operating positions #1 through #6.
We now have all 16 of 16 potential tone set frequencies in use between RS and BL. To add a 17th keying channel would require a second voice grade path between RS and BL.
Last, I brought along some prototype LED replacements for the 24PSB bulbs used in the antenna select switches. Both worked. The 15000 mcd LED was brighter than the other. These were made from cylindrical dome lens LEDs and there are other package styles that might be more appropriate for illumination so before we go into volume production I'll do more research and make a few more prototypes.
|Bill's test examples of a LED replacement for the 24PSB (bottom) lamp. They work great.|
One tip that I learned a long time ago was to cut off the dome on these LEDs. This changes the illumination from a more-or-less focused spot to a broader beam.
Bill Ruck (RK)
MRHS Maintenance> Fantastic Donation to the MRHS
When we have visitors of make presentations to groups we sometimes drone on about how, in the point to point service, they used keying heads like the Boehme we have in service at KSM to shove traffic over the circuit at speeds of 100+wpm.
|Video: Boehme keying head in action at KSM|
We then go on to explain how at the receiving end the incoming Morse was copied on paper tape with an inker that produced a squiggly line representing the dots and dashes and how - unbelievably to some - these tapes and their squiggly lines were drawn in a slot before guys who read them and typed out the message. By this time we usually observe a lot of glazed expressions because it's hard to picture exactly what we're talking about.
|Video: BC-1016 Morse code tape inker |
But now comes Mr. Rob Flory - a real True Believer by the way - who made us an offer we could not
refuse: a BC-1016 inker of exactly the type used at the receiving end of those high speed circuits. He graciously offered the inker to us on condition that we show it proper reverence and provide it a good, safe home. We were able to agree to these conditions without reservation and presently the machine arrived courtesy of Mr. William Donzelli and his boatanchor express service.
|BC-1016 and two tape pullers in the MRHS storage area awaiting cleaning before being put into service.|
We plan to demonstrate the BC-1016 to visitors who display the tell-tale signs of being True Believers and who whisper the secret word "inker" at the proper moment. But there's a little hitch. The unit requires 3/8" paper tape and the only supply we have is that shown on the tape puller in the photo above. So if anyone can direct us to a supply of the needed tape please send an e-gram to email@example.com.
> MRHS Tries Twitter - Worth the Effort?
As announced in Newsletter 37 the MRHS has, with a worried demeanor and trembling hand, dipped its toe into the strange and unaccustomed waters of modern communications by trying Twitter. The idea was that we'd send out real time reports of KSM and K6KPH operations, information like "KSM 8Mc transmitter off air" or "K6KPH now guarding all channels for calls".
At last count we had 37 followers.
If you want to become follower 38 we're @Radiomarine. If you're not a Twitter user you can sign up for free at https://twitter.com/
What's your thought about this venture? Is it worth the time and electrons? Please let us know with a note to firstname.lastname@example.org.
> Archivists Corner
by Carola DeRooy
Archivist, C.A. & Museum Collections Manager
Point Reyes National Seashore
Carola is on vacation for the next few weeks. But she hasn't forgotten the True Believers. Seh's sent along some very interesting scans including those of the 1949 RCA Guest Book maintained at the Point Reyes receive site.
Please note that we carry on with this tradition. When you visit today and you're asked to sign our guest book you'll be following in this great tradition.
About the historic guest book from 1949, Carola writes:
You will note that in 1949 following the war that the station had a number of Japanese telecommunications ministers visiting and an RCA-C rep from Tokyo. On the same page are also visitors from Kohoku and AT & T folks from NY.
> Operations Report
by Richard Dillman
KSM transmits on 426, 500, 4350.5, 6474.0, 8438.3, 12993.0, 16914.0 and 22445.8kc CW,
6328.0, 8433.0 and 12631.0kc RTTY.
K6KPH guards 3550.0, 7050.0. 14050.0, 18097.5 and 21050.0kc
Station contact: Phone +1 415-669-9646 (answered only when station is on the air)
Hours of operation: 1000 to 1600 Pacific time Saturdays
Maintenance working on keying lines. Successfully migrated K6KPH transmitters to former WCC control panel.
Bands wall to wall with Field Day operations so no general amateur contacts were made.
Traffic list and weather out at 2100Z and 2130Z respectively.
No ships today.
As a result of migrating K6KPH to WCC panel we can run a wheel on K6KPH. Began running wheel at 2030Z on 3550 and 7050. Didn't want to run the wheel on the longer distance channels but those frequencies seemed dead for the most part.
2106Z Bob W7NV from Oregon called with a good signal on 7Mc
2156Z K6BZZ Dick in AZ on 7Mc
2309Z Tom from Arizona nice chat and good signal on 7Mc
This was a banner day for KSM.
Bolinas advised that 22Mc was off due to antenna work by the H Set Crew. But then came the news at 2200Z that Transmitter 298, the H set that has been under restoration for more than a year, was on the air on KSM 22Mc. The signal sounded great at the receive site with good keying. Wonderfully great work by the H Set Crew. See the full details in the lead story of this issue of the Newsletter.
Traffic list and weather went out at 2100Z and 2130Z respectively.
2207Z garter snake found in Frank Geisel's former office, guided back outside
No ships today.
> MRHS Merchandise
Support the MRHS and look cool at the same time. Such a deal! We've got hats, mugs, T shirts, belt buckles and bumper stickers, all with variations of the MRHS logo. Get a hat and mug for yourself and a put yourself in solid with the XYL by getting her a MRHS hoodie.
Just click on the images above to go to the MRHS True Believers store and browse our offerings. Thanks!
Until next time we wish you fair winds and following seas.