I'm sorry to trouble everyone. I am a radio enthusiast from mainland China. I was recently trying to assemble a radio transmitter of my own. When I was counting the radio parts I collected, I found one in the inventory that I had previously handled at the broadcasting station. I bought an 813 vacuum tube for about 10 US dollars, but due to the location in mainland China. During the Cold War from the 1960s to the 1990s, amateur radio transmission activities were banned to prevent espionage activities. As a result, there was almost no information on radio transmitters in the local area, so I used Google to search for relevant information.And found "The-Radio-Amateur's-Handbook" 1956 and found an article in it that matched the vacuum tube parts I currently have and the transmitter that met my requirements.
But I encountered the following problem
I don’t seem to find that the coil data given in the article includes the diameter of the wire used for coils L1 and L2, the number of turns and the diameter of the coil, and the diameter of the coils L1-L9. The diameter and number of turns of the wires used do not seem to be complete. Please forgive me because my English is not very good.
Regarding the coil problem, I can calculate the required parameters by myself by consulting relevant information, but one thing that gives me a headache is that I don't understand the labels such as B&W 3015 and 2 and 4/3 inches. What do these two mean? After all, the units marked in China are public units. I hope you can answer them for me one by one.
Another question is whether this transmitter can transmit these two signals as long as it is connected to an AM or SSB modulator?

B&W means "Barker and Williamson," an old and honorable company that made many things including pre-wound coils. Pre-wound means they were already made and life was simpler when making a transmitter. 3015 was the part number. The B&W catalog would show you all the measurements of each part number, but they are in English inches and not mm.

There is probably a B&W catalog from the 1950's on-line and someone can direct you to it. Then you could just convert measurements to mm. The catalog should show the measurements.

A grid dip meter would be an enormous help in building this. But I do not know if those are available in China. These days it is easier to get test equipment and parts from China than it is in the USA!

I think that is the Vernon Chambers transmitter. Vernon was an amateur who designed it and a few other things and it was a popular project. The 813 is a very good and strong tube.

That appears to be a code only transmitter. It could probably be connected to a modulator and used for AM at reduced power. But AM isn't used much on the ham bands any more. Some modifications might also have to be made depending on how it is keyed.

For SSB, the final amplifier is about all that would be useful and that would have to be redesigned to be a linear amplifier. The rest of the transmitter is useless. You could build a phasing type exciter around it but it would be a lot more complicated and would be tricky to adjust. A filter type exciter requires a filter which might be hard to get. If you want SSB, check with later handbooks that show how to build one.

The easiest solution is to learn the code an use it for CW.

It has provision for using a cathode modulator, which is not described in the article. Kind of odd that there would not have been a plate modulator intended, considering the level of construction involved.

I have not heard any AM activity in that part of the world, listening from Hawaii or S. Korea, so yes, it would be rather lonely calling CQ on AM.

Building that transmitter today would seem rather heroic considering the difficulty of finding parts 67 years later, and how complicated it is.

every now and then when the stars align i get ham voice am on my sx-42. this is mostly on the weekends. judging by the accents i assume they are kiwi's or australian but its a rare event, my sx-100 fared no better its about the same for cw but my antenna could be a lot better too.

2.75 inches is 70 mm. I imagine China uses metric measurements? You can use google to find English to metric converter. google search inches to millimeters.

The B&W coils are usually wound with wire that's 1 to 2 mm diameter. I think the photographs in the ARRL Handbook show some coils and they can give you an idea of their size and construction. I would go ahead and construct the transmitter and worry about the coils later. When you are ready for them I would find small diameter stiff copper wire and wind a coil that resembles the photograph coil. The wire has to be stiff enough to support the coil without anything holding it. If that is not possible you can cut a piece of wood or plastic to insert in the top of the coil to support it. Then you can compress or stretch the coil to vary its inductance and see how the circuit works. I believe there are handbooks with typical values of inductance for certain LC circuits for different ham bands.

With a separate modulator using a pair of 811As for example, you should be able to modulate the plate of the 813. You will have to find a modulation transformer of course. You can run the modulator off a separate power supply or build a power supply big enough to power both the 813 and the 811As or whatever tube you use. You could use four 807s.

The above parts are all easily available in China, because in the last century, Chinese radio factories produced a large number of radio parts in response to possible wars, and the remaining stocks can be easily purchased to this day.

Thanks for your answer

I am glad parts are available.

What is left to find?

your English is excellent.

Here are the expected coil inductances:
L1 = 35 uH
L2 = 93 turns of 0.1 mm wire on slug-tuned coil form 12 mm diameter by 17 mm long.
L3 = 2.6 uH
L4 = 5.3 uH
L5 = 1.5 uH
L6 = 8.9 uH
L7 = 5.1 uH
L8 = 4.2 uH
L9 = 1.6 uH

L7 is 10 turns 64 mm diameter, one turn every 4 mm made with 2 mm wire

L8 is 9 turns like L7

L9 is 6 turns of 6 mm copper tubing 57 mm inner dia by 70 mm long.

L7 and L8 can be formed from one B&W 3905-1 which is still available:
https://www.bwantennas.com/Mini.html

RFC 1 is 129 turns of 0.4 mm wire on a ceramic rod 18 mm diameter.

73 Chip KM4SJN

Thank you for your answer. English units are really a headache