Plug-in coils identification

[stevef]

I have some plug-in coils which appear to be like those in the BC-610 and the B&W HDVL series, however the numbers are different.

Printed on the ceramic bases are;
1537  63407-1
1538  63408-1
1539  63409-1
1548  63421-1

Who made these puppies and what were they used in?

Tnx, Steve KK7UV

[k4kyv]

Can you post photos?

Most of the manufactured amateur, commercial and military coils have the frequency range stamped on the ceramic bar.  Much more convenient for the operator not to have to look up the reference number to decide which coil to use, particularly while under mortar fire.

[Barrie]

Steve:

There's considerable difference between the BC-610 coils, which were known as "500 watt coils", and the HDVL coils, which were 1000 watt coils.

Do you have an inductance meter?  If you do, measure the inductance of 1/2 of the coil windings and relay that information to me.

I have quite a number of these coils and I could tell you what frequency range they were intended for.

If you do not have an inductance meter, bring the coils down to the shop and I will measure them.

73, Barrie, W7ALW

[stevef]

Upon closer inspection, there are remnants of Barker-Williamson labels on the ceramic bars.  I found an intact label for a positive brand i.d.

Using an Elenco LCR-1810 meter, I get the following inductances Barrie.

1537  63407-1:   1.0 uH across half the coil, 8.0uH full coil
1538  63408-1:   Too low for a reading.
1539  63409-1:   Too low for a reading.
1548  63421-1:    2.8uH half coil, 9.8 uH half coil.

I'll have to bring them by for you too look at closer Barrie.  If it helps, here's a couple pics.

[Barrie]

Steve:

Those numbers don't make a lot of sense.

If, for example, you read 1 uh across half a coil, and 8 uh across the full winding, something is wrong.

The full coil should be double half the coil.

The BC-610 coil I use for 75M reads approximately 25 uh on each side.  The full coil reads 58 uh.  The 8 extra uh is caused by a rotating link within the coil.

From the photos I think these coils have been modified, or were built for some special purpose.  In any case, the inductance appears to be too low for 40, 80 or 160 meters.

73, Barrie, W7ALW