Tapped inductors, LC IF-filters, where?

A useful alternative is winding your own using toroidal cores. Most radio amateurs do that these days when constructing their own equipment.

Leon

Also, not many brands. Digikey doesn't have any, Mouser

They had to, because even a $10 radio contained half

Actually, I'd like to know, too, these things are usefull. Unfortunately they are a bit of a speciality item and shops charge premium for such stuff.

The new car radio tuner chips I checked out had a ceramic resonator in first IF and second IF (455KHz) for FM was on-chip and adjustable bandwidth.

Mark

Sure, I do that all the time for lab gear. But this was meant more for production. Sometimes the quantities aren't quite high enough for a custom version.

and 455kHz IF filters which also can be used as such.

Also, not many brands. Digikey doesn't have any, Mouser

They had to, because even a $10 radio contained half

are

They used to be widely available for little money. No more :-(

IF and

That's what I am afraid has killed the market for those filters. Just like those practical little audio transformers. One day the industry figured out how to build radios without them and they became extinct.

You do know Neosid, I presume? It's admittedly been ages since I last bought filter coils from them, and I don't remember them as cheap.

Jeroen Belleman

Sure I do but their prices were mostly way out of reach.

IF and

those practical little audio transformers. One day the

Yep, ceramic (10.7) or on-chip filtering (low if) is probably making a dent.

Mark

Try:

Look for the passive product matrix PDF above the top LH corner of the main panel.

Its a large group of companies, so it may have a facility local to you.

Actually, that's what we did in one case. A Taiwanese shop wound them for us on a machine, final cost was around 35c a pop. But that only works if it's tens of thousands a year, preferably in the six digits.

Think who you're talking to. You have a lot more time than, a whole lot of people I'd say, if you want to custom wind ten thousand of them! :^)

Tim

-- Deep Fryer: A very philosophical monk. Website @

Thanks, Ian, but that's the usual suspects. They only have ceramic resonators.

Nothing here:

That's just inductors sans tap, only adjustable. Toko does have filters but the selection has shriveled to stuff like these 3.58MHz chroma filters:

I usually need more extreme tap ratios (or impedance ratios). But even these 3.58MHz will likely go lalaland soon because analog TV is gone for good in the US next year. It's going to be a 100% cut, there won't be any analog stations left by the end of February. Meaning no chroma carriers either.

Some of the PDF sheets I downloaded from that page contain a notice inviting customers to enquire about detailed specifications - have you tried doing that?

Not yet. I am looking for something that's available off the shelf and where there is a chance that it's going to stay that way for a decade or two. Else I can't really use it in a new design.

Not true, there will still be LPTV and analog cable... not to mention Canada, Mexico, etc. Also, parts that are useful in ATSC to NTSC converter boxes will be popular for a while longer.

Right, but the sets will most likely do all this in a baseband DSP setting. The ATSC to NTSC modulators won't have LC, just a 3.58MHz crystal. Maybe not even that if they contain a modulator and generate it from another reference. Last time at CostCo it seemed the regular sets have already gone extinct, all flat screens.

The converter coupons arrived yesterday BTW. However, so far it looks like OTA DTV isn't going to very reliable out here, pretty much as I had expected :-(