Capacitor replacement

This pic shows an old Collins broadcast transmitter at the California Historic Radio Society Museum in Alameda. Note the separate power switches for filaments on the left, and plate supply on the right.

500/1000 watt.

Kinda tiny for a transmitter, no?

WLW used to have something with a little more kick……..

I always thought small radio stations were in the 50kw area?

All depends on the service.

Some of the modern AM information transmitters are only 10 Watts and are 1U high rack space.

You children are too young to remember, but back in the day there was one I remember well. WWVA in Wheeling, West Virginia. 50 kW clear channel, and at night it could be heard, pretty clearly, from Denver to Boston and on down to Houston or Miami. Truckers and trucker families used it to send messages to each other — a few country songs, then a bunch of messages ("Sue Ellen, I'll be home around 5 this morning, Big Dog" — that sort of thing). Long before cell phones. Long before CB radios (although it supplemented them — they were short range). Those were the days… as Kathy Mattea sang, 18 wheels and a dozen roses"… or Alabama — Roll on!

I don't recall but my guess is 10s of thousands of volts. The weren't electrolytic. They could discharge very rapidly.

the clear channel stations are frequency coordinated to not interfere with each other when you get long distance propagation on the low bands. there are many stations in far away cities on the same frequencies as the clear channel stations that have to reduce their power or go off the air and possibly change their antenna pattern at night as part of the clear channel plan.

I'm in central CT, and I can pick up WFAN NY pretty clear (they carry the Yankee games), but it depends on where - there is SO much AM interference these days I'm convinced the federales are ignoring Part 15 when it comes to AM interference. Some streets in my small town are awash in noise, and the next street over I can pick up NY just fine. Odd.

@MaxMercy

That was my point I forgot to post about above. I am in Chicopee 10 min north of Springfield. I can't get the Yanks at all. They are supposed to be on a Hartford station 97.9 FM but no dice here no matter what radio I use.

@EBEBRATT-Ed I am probably hundreds of miles from your area and I can hear WUCS 97.9 just fine (on my computer). May work on a phone too.

https://mytuner-radio.com/radio/wucs-97-9-espn-427934/

https://mytuner-radio.com/radio/wucs-97-9-espn-427934/

I just assume the SMPS used in all modern stuff including LED lights is just noisy.

Correct, "modern" is the key, but it doesn't have to be that way. Careful design, component layout, and shielding will eliminate this.

1920s-30s "farm" radios used three batteries, and batteries in those voltages are hard/cobble together to find, and of course, don't last all that long. Back in the 1980s I built a SMPS based on an RCA CTC140 TV circuit (I used the transformer from a scrapped board) to make a battery eliminator for a Zenith tombstone farm radio that was in my buddy's family for 60 years. It worked perfectly and generated very little noise. These days, you can buy a smps based eliminator for use with antique AM radios already built.

the fcc doesn't have the funding to care about anything unless it affects the cops.

a huge part of the problem is that lots of stuff is sold through channels where it is almost impossoble to stop stuff that hasn'r been tested from being sold.

also, try finding a part b ballast for an 8ft florescent.

in a lot of applications.

Think we need to open an electronics section on this forum

Ok, let's rename it to "Valve and Condenser Replacement" That'll get rid of the confusion!

Ok so.

Who knows the reason why beam power tetrodes exist vs pentodes without looking it up?

It has been too long, I did know that decades ago. When I looked it up, I said, Oh yeah I remember that now.

Its funny, but sad, when they gave up printing the books and just went with the PDF datasheets of just the device you lost a bunch of information. A scan of the whole book is better IMO.

automotive stuff usually isn't too bad. they have an interest in keeping interference out because they don't want their car stopping or freaking out if you drive through an rf field. that design to reject interference does a pretty good job of containing most interference too. they also don't want one part of the car interfering with another part of the car.

when i tuned my flex 5000 to the am broadcast band on whatever random antenna it was connected to at night I saw many am broadcast stations on the panadapter. they seemed to be 100% ads for products that could only be described as scams, but the stations are there. If you are outputting 50kw you are using at least 2x-3x in power although I think the cheat the carrier in modern am broadcast to reduce the power consumption some.

most radios included in things in the past 20-30 years have not been good receivers but just an afterthought added on. car radios tend to be better but they may have gotten worse recently as they expect you will just connect the amp to some external device.

My 1977 Dodge, AM only, radio was excellent for reception. Actually kept it when the van was sold.

My 1984 Ford van radio is almost as good with the AM.

Yes, that is a retired ambulance van I use for work…..when the mood strikes.

Extended height I can stand up in.