Tapped inductors, LC IF-filters, where?

[Joerg]

While contemplating a new design I was looking around for tapped
inductors and 455kHz IF filters which also can be used as such. Got a
sticker shock. Even at quantities they can't be had under 75c. Ouch!
Also, not many brands. Digikey doesn't have any, Mouser only carries one
(Xicom).

Are LC IF filters finally going lalaland? I remember them to be really
cheap. They had to, because even a $10 radio contained half a dozen of
those.

 

[Leon]

While contemplating a new design I was looking around for tapped
inductors and 455kHz IF filters which also can be used as such. Got a
sticker shock. Even at quantities they can't be had under 75c. Ouch!
Also, not many brands. Digikey doesn't have any, Mouser only carries one
(Xicom).

Are LC IF filters finally going lalaland? I remember them to be really
cheap. They had to, because even a $10 radio contained half a dozen of
those.

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

Leon

 

[TheM]

While contemplating a new design I was looking around for tapped inductors and 455kHz IF filters which also can be used as such.
Got a sticker shock. Even at quantities they can't be had under 75c. Ouch! Also, not many brands. Digikey doesn't have any, Mouser
only carries one (Xicom).

Are LC IF filters finally going lalaland? I remember them to be really cheap. They had to, because even a $10 radio contained half
a dozen of those.

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

 

[Joerg]

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

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.

 

[Joerg]

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.

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

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.

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.

 

[Jeroen Belleman]

While contemplating a new design I was looking around for tapped
inductors and 455kHz IF filters which also can be used as such. Got a
sticker shock. Even at quantities they can't be had under 75c. Ouch!
Also, not many brands. Digikey doesn't have any, Mouser only carries one
(Xicom).

Are LC IF filters finally going lalaland? I remember them to be really
cheap. They had to, because even a $10 radio contained half a dozen of
those.

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

 

[Joerg]

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.

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

 

[TheM]

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.

Regards, Joerg

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

Mark

 

[ian field]

While contemplating a new design I was looking around for tapped inductors
and 455kHz IF filters which also can be used as such. Got a sticker shock.
Even at quantities they can't be had under 75c. Ouch! Also, not many
brands. Digikey doesn't have any, Mouser only carries one (Xicom).

Are LC IF filters finally going lalaland? I remember them to be really
cheap. They had to, because even a $10 radio contained half a dozen of
those.

Try: http://www.abacus.co.uk/jkcm/Products/Passive

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.

 

[Joerg]

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! :^)

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.

 

[Tim Williams]

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

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

 

[Joerg]

Try: http://www.abacus.co.uk/jkcm/Products/Passive

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.

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

 

[ian field]

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

Nothing here: http://www.toko.co.jp/products/en/coils/index_variable_e.html
then?

 

[Joerg]

Nothing here: http://www.toko.co.jp/products/en/coils/index_variable_e.html
then?

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:

http://www.toko.co.jp/products/en/filters_lc/fss_e.html

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.

 

[ian field]

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:

http://www.toko.co.jp/products/en/filters_lc/fss_e.html

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?

 

[Joerg]

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.

 

[Joerg]

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 :-(