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Excellent question. One can tell the answer without even asking. Sometimes it takes a little while.

Output network caps in the usual pi or pi-L will have a lot of voltage on the tune cap and a good amount of current on the load cap. Doorknobs will work as padders for a load cap but each unit must be carefully choosen so as not to exceed it's current capability. The circuit might need 800...

If one adjusts for inflation based on the original prices both are now dirt cheap.

The easiest way to reduce the voltage in that radio is replace the tube rectifier with solid state diodes and use the original rectifier filament winding to buck the primary. That is hook it up in series with the winding in opposite phase. Those 2 tricks will lower the load on the power...

cb could become very popular again if cell phones and the internet evaporated and the sunspots stop. Otherwise nah.

What Maxwell wrote is simple and true. An antenna coupler redirects the reflected energy toward the load. Almost all energy is radiated. This holds true if the coupler is not used at extremes of its capability into open wire line. Coils get hot and melt when the coupler is mis-used...

A properly sized variac shouldn't be that much of a voltage regulation issue. A marginal one could be.

That quad 807 direct coupled audio driver was sweet. Try taking the pair of 807 rf drivers up past 2 mhz with the layout in a Gates. Not fun. That's where a 6146 really comes in handy.

Don't take any information seen on the internet seriously unless you have actually heard those providing said information on the air.

I think you have it flipped around. More coffee. The 807 was based on the 6L6. It's a squirrley S.O.B. to tame if the layout isn't just right. See BC-610 driver section......

Some good advice here. Do not trust capacitor banks to have their negative lead connected to chassis ground. There's usually a meter multiplier resistor in series. If the person before liked to zap the caps to ground with a screwdriver the resistor can be burned open. Always lean across each...

30S-1 and it is only a 52 year old design. That was just yesterday :biggrin: Before the 1500 watt P.E.P. rule went into effect legal limit amps had a CW and SSB position which usually changed plate voltage via taps on the plate transformer. Most did not actually change the zener used for bias...

Amateur rigs went from sweep tubes to 6146s most likely due to perceived cheapness of sweep tubes verses the 6146 being a real rf tube whatever that means. The 6146 is a refinement of the 6L6 and is a very nice class C rf tube. Of course the idea holds no water and the 6146 is actually a...

And Drake sold a lot more with sweep tubes. Drake was considered top quality.

It would be interesting to take your old cable and measure it's loss.

A linear amp uses the same bias voltage on AM as it does on SSB and should produce almost exactly the same peak output.

As long as dissipations are not exceeded pulse rated tubes work just fine for hobby radio. Usually pulse rated tubes have very robust filaments for extra peak emission. In some cases the filament burn can be safely reduced for longer life.

Galaxy WRL made a 10 sweep tube legal limit amp. Nothing wrong with sweep tubes at all except many amps run them so hard. Some of the very worst linear amplifier tubes are the 6146 and 4CX250B. The feedback needed to clean them up can be applied to sweep tube amps with excellent results.

Where are these 811 driving 813 setups found? The only ones I've seen are 813s plate modulated with 811s which of course isn't an rf linear amp.

Some CB amp makers disguised their stuff as amateur amplifiers. No really good 6 meter tube amp would have capability on 10 also. The tank values and layout would make it a lousy performer. One special case would be a really complicated mechanical arrangement like the Heath Seneca used on 6 and...