Rev. Robert P. Chrysafis,
I see you name popping up on the internet in relation to searches for information on the J.R. Cunningham CM 30-50 Transmitter.
Rev. Robert P. Chrysafis,
I see you name popping up on the internet in relation to searches for information on the J.R. Cunningham CM 30-50 Transmitter.
I acquired a J.R. Cunningham CM 30-50 Transmitter along with the LPB ATU-100SF Antenna Tuner.
A friend of mine is in the AM radio business and he had it stuffed in storage for any number of years. He had removed it from a Transmitter site in when they upgraded. It was being used as a backup Xmtr and currently has a 1050 kHz Xtal installed, but I have a FCC-1/FCC-2 NorCap QRP DDS that I should be able to use instead of crystals.
Do you have any information on this thing?
The original builder, Mr. Cunningham, passed away 2 years ago... and no one seems to have Tech info on these things...
If you could help, that would be great. Please let me know.
Bow
The good Reverend and other folks have uploaded some files to the library here that might be helpful
Cunningham's seminal writing on low power transmitters, Missionary Edition
http://part15.us/files.p15/melprb.pdf
Cunningham's "The Big Antenna Book"
http://part15.us/files.p15/tbab.pdf
A Marketing brochure for an LPB ATU
http://part15.us/files.p15/ATU%20Series.pdf
Thanks,
I am thinking LPB is out of business... Every phone number I have called for them is not working... Or now belongs to someone else!
The good news is that I have got a full manual with Schematics for my Cunningham transmitter!
LPB is not actually out of business, but just hard to reach. I don't know what is going on with this company, but it looks like they will only speak to people they know, and not to the general public. The Camden, N.J. telephone numbers on their website do not work. Their current telephone number is 267-252-5092, which is a Philadelphia number. My experience in calling LPB on this number is that, if they don't recognize your name, they say "hello-hello," and hang up.
But it wasn't good. Saw a low power transmitter, ATU and TIS style antenna aggressively sold to a local institution about 5 years ago and absolutely no customer service at all.
The items were misshipped, damaged and then forwarded to the local customer direct from the misshipped destination. Dead on arrival at the local site.
Weeks of waiting for telephone support, no telephone support provided. LPB begrudgingly agreed to inspect the XMTR, ATU and ANT if shipped both to LPB and back at customer expense, which the customer did.
LPB reported "all A-OK" but when the shipment arrived back from LPB it was in the customer's original packing and had never been opened by LPB - they just swapped shipping labels, sat on it for a couple of weeks and sent it back.
It doesn't seem like there is much risk of LPB taking any more orders from the sounds of their current "customer experience promise," but just in case they come out of the woodwork to try to take someone else's money, that's what dealing with them was like for me.
From court papers posted on the Internet, I learned that, in 2007, the Federal District Court in Camden, N.J, found LPB to be in breach of contract relating to an order for seven 10 kW HF transmitters. Only one transmitter was delivered to the customer, and it was incomplete and defective. It was around the time of this court decision that LPB stopped answering the phone. I don't know if this was because of the court case, or some other reason.
it's a shame. LPB use to be THE low power am company to go to as late as the 70's maybe into 80's. one has to wonder what happened.
I also own one of these fine transmitters and carrier-current coupler with documentation (and it's for sale!!). Shoot me an email at; lakeshoreradio at gmail dot com. Maybe I can help you out on the docs.
M.S.
Full manual for the Cunningham CM30-50 transmitter scanned into PDF format.
Cool, I hope someone can use it...
The transmitter has has been very altered... New power transformer (High Voltage, lower Amperage), different rectifier circuit, changed filter caps, changed bias section...the previous owner really screwed it up...
It is supposed to have 450V coming out of the Rectifier.. mine is closer to 580V....
So all the tube voltages are too high, so I need to find a 450V, 300ma power transformer before I go much further...
But, I hope someone can use the Manual!