Hi, can anyone can help me with the following question or pass on my question to someone you know that might be able to help me:
1) I am looking for a working Western Electric Model 13c transmitter. This transmitter was manufactured in the 1930's through the early 1940's. It was capable of transmitting at 50 watts of power.
It is extremely unlikely you will find a working 13c for this effort, and if you do, do you really want to put all your eggs in that basket without a more modern, dependable, backup? It would be a shame to get out on the island and find that the finicky old 13c was not up to snuff when any old off the shelf modern transceiver would do.
You need to define that “50 Watts of power”, was that 50 carrier Watts? Or was it 50 Watts PEP? Total output power. Sidebands plus carrier?
Since the 13c used dual 282A tubes on the final RF amplifier I suspect it was capable of 50 Watts of carrier and 100% modulation, which is more than 50 Watts of output.
2) If I can't find a working Western Electric Model 13 c mentioned in (1) and it's not looking good, I would be willing to look for any 50 watt tube type transmitter capable of receiving crystals for transmission on the AM band.
Why specify tube type or crystal controlled? A transmission is a transmission is a transmission. If it is on the right frequency (be it modern digital or crystal controlled), if it is in the right transmission mode (AM is a mode, not a band), and if it is at the right power level, there is no real difference between a modern radio and a 80 year old tube radio. Other than minor variations in the way they sound there is no difference in performance capability.
If I can't find that, then I would like to find any newer model 50 watt transmitter capable of sending signals on the AM band.
Again, AM is a mode, not a band. AM can be sent on any band, any frequency, although by convention it is not used on many today.
There are many radios made today that will do what you ask. Licensing is an issue, you do need a license to transmit. However if you are not particularly worried about that most modern ham radios can be MARS/CAP modded and transmit on those frequencies.
Use of such a radio may or may not be legal, depending on what specific island you want to operate from, and what licensing control that territory falls under.
This has to do with travel next month to a remote island in the Central Pacific by a team of researchers. One of the things we are going to attempt is a recreation of what we believe were post loss radio transmissions from Amelia Earhart in 1937. We believe she transmitted radio distress messages for several days on either 3105 and/or 6210 kilocycles.
Your help and any assistance would be greatly appreciated.
You have a few other issues in this endevour.
Based on your statement above, “next month”, you will be making transmissions in Dec of 2016. I think the scheduled dates of transmission are Dec 14 and 15, 2016, at 1900 UTC (1400 EST) each day?
Have you considered that holds essentially no relationship at all to potential Earhart or Noonan transmissions?
Earhart went missing on July 2, 1937. The reported receptions occurred over the next few days. That was mid summer, and your planned reenactment dates are in the winter. Propagation (the way radio travels from one location to another) is very different between those two times of the year.
Early July, 1937, was almost the peak of Solar Cycle 17 (actual peak April that year), Dec 2016 is on the downwards side in a singularly low Solar Cycle 24. Propagation will be extremely different from what was encountered in July of 1937.
When you look at the frequencies used the impact of this becomes even more important. 3105 kHz and 6210 kHz. And some have claimed that some of the transmissions were heard on harmonics of those frequencies. That is two different issues.
3105 and 6210 kHz are at the lower end of the HF band. They have specific propagation features. Both of these frequencies propagate well at night, and poorly during the day, for long range they want a nighttime or dark path from transmitter to receiver. They propagate over moderate to short distances in a fully daytime path. You proposed reenactment time of 1900 UTC is roughly near sunrise at the source location, but mid day to afternoon in the US.
If you combine the current Solar Cycle conditions with time of year, time of day, and frequency selection, it simply is not going to work. Or rather, I should say, without some exceptional, unpredictable, and far outside the norm, conditions, these transmissions will not be heard in the US from such a transmission location.
However the conditions today are FAR better than they would have been in 1937, since at that time, given the same factors, the transmissions were even less likely to be heard. While the current conditions to hear such a transmission are abysmally poor, they are better than the conditions that existed on July 2, 1937. All of the factors above that I indicate are working against you were worse in July of 1937.