[HBR] IF's winding

[Ian Wilson]

Most 455kHz IFTs that I've measured show up as about 1.3mH (this is measured
at a
test frequency significantly below 455kHz, so the effect of the tuning
capacitors is
negligible).

If the tuning caps are also scaled proportionately (anyone know if they
are?), I would
expect 120kHz IFTs to have inductances of around 5mH.

You can also test unknown IFTs as follows:
  - identify pairs of windings (ohmmeter)
  - apply signal generator to one pair of windings
  - apply scope (or AC VM) to the other pair
  - tune signal generator, look for peak (start at low frequency and work
up)
  - switch windings

Regular IFTs will show similar behavior with the windings swapped. 'Output'
IFTs
will show a resonance only when connected with the tuned winding to the
scope
or AC VM.

73, ian K3IMW