PW-15 Transmitter at Coast Station KSM

This PW-15 transmitter was recovered from the KFS transmitter site. It is thought to be the last PW-15 in operation. It is now the 12Mc transmitter for coast station KSM, operated by the Maritime Radio Historical Society.

Category:

Howto & Style

Tags:

• radio
• KSM
• morse
• code
• transmitter
• short
• wave

[ttyradio]

Thanks for keeping this wonderful stuff alive. And the spirit of maritime radio. Alway had a fascination with marine radio. I hope to copy you guys on RTTY with my model 28 . Kind Regards

[RadioKSM]

Thanks for your note. We feel very lucky to be part of this project. Good luck with the Model 28. I hope you have seen our video of our two Model 28s in action.

[nokomarie1963]

That was awesome. My mother used to be in the WAVES and that was her job, translating morse code messages for the Navy in WWII. Thanks for the look.

[RadioKSM]

It's our pleasure. It's women like your mom that we try to commemorate and honor through our project. Might you be able to tell us more of her career for inclusion on our Web site?

- RD

[RadioKSM]

When Globe Wireless owned this transmitter they replaced many of the mercury vapor rectifiers with solid state devices (as seen in the video), removing the filament transformers and wiring in the process. Since this video was made Sr. Transmitter Engineer Steve Hawes has reversed that conversion, replacing the solid state devices with the original mercury vapor rectifiers. Now when the transmitter is on the air you can see the rectifiers flash through the windows in the front doors. - RD

[cadillacad]

Thanks for posting! May I know how the transmitter is coupled to the antenna? Is it thru coax cables? Is it gonna be on-air for long?

[RadioKSM]

As originally built by Press Wireless in the 1940s it had balanced output and fed its antenna via open wire line, the standard procedure for the time. In the 1970s Globe Wireless, the former owner, made many mods to all their PW-15 transmitters (12 were in service) to meet new, tighter FCC specifications. One of those mods was a conversion to unbalanced coaxial output. The transmitter is used on special occasions for the KSM 12Mc CW frequency. - RD

[jaysee69]

Wow!! I got goosebumps of excitement watching that big old transmitter keying up!! I'll never forget the time I was out bicycling around Rutgers University in New Brunswick NJ (1961) and I came upon the VOA Bound Brook transmitter site -- being an enthusiastic 18 year old ham, I boldly went up to the front door and knocked! The lone op on the site let me come in and showed me the INSIDE of the transmitter, where he was about to change frequencies and antenna and re-tune. What an experience!

[gmcjetpilot]

Oh my gosh....how awsome! Love the tubes. Have to get me some tube gear. Whole building shakes......great! Thanks

[RadioKSM]

Heh. Well, it's a 15kW (originally) air cooled transmitter with lots of tubes. So the noise is all the blowers needed to keep the tubes cool. When we run this transmitter plus all the other vintage air cooled RCA transmitters on the second floor the whole building vibrates. - RD