The AM Forum

I would assume that I'd want to saw open the core, remove one leg of the secondary from ground, remove the powdered-iron shunts, remove the and toss the primary, reassemble, spot weld the core back together. Done!

But hey, its free and plentiful, right? Whattya think?

-Jason kf6pqt

One problem is that even removing the grounded side of the secondary, there probably isn't a lot of insulation between that end of the winding and ground - and unlikely enough room to add any.

But you could let the whole thing float at HV potential.  No need to even unground  the wire.

Be sure to leave a gap in the core so that it doesn't saturate with the DC flowing through.

I once made about a 35-40 Hy mod  reactor out of two identical 12 Hy power supply filter chokes.  Took them apart, discarded the I-laminations and clamped the cores with E-laminations together so that they faced each other, with each E-core replacing the I-lamination of the opposite choke.  Then wired the two windings in series, properly phased.

Normally, just wiring the two chokes in series would have  resulted in a total of 24 Hy, but by combining the cores, theoretically the total inductance should have been 48 Hy.  But it never quite measured up to that.  Probably because of the loss of iron that resulted from discarding the I-laminations.

John, WA5BXO used that reactor in his homebrew rig for years, until the whole station got carried away in a flood.  He managed to find the rig in a sinkhole, under water after several weeks.  Amazingly,  he took the whole thing home, dried it out, and got it working again.  Last I heard he is still using the mod xfmr and that homebrew reactor.

Under water AND mud, thats awesome!

I have several of these things to experiment on. The gap may present a problem, cutting up the I-section. Since these are just steel laminations anyway, theres probably no reason against just replacing the I-section with a different, say 1/4" thick piece of steel?

-Jason kf6pqt

 :)

Check murphy surplus??
Check Apex
You would have to cut an air gap in the core of PS transformer to not saturate.

Part of the drive here is attempting to make gold from garbage...

I struck out with TV repair shops back in '98.

2m repeaters? Hah! Either void of users, or closed/private.  Asking a ham on 2 meters around here for parts for homebrew is a 1 in a 100 shot. Most are the sort who "don't like getting their hands dirty" and the remaining few would demand ebay prices for whatever they had, if they had it. I mean, its 2 meter FM, for crying out loud!

My Spanish isn't good enough to cold-call an AM station. ;)

Sorry to sound so negative, but balance the snobby, money-obsessed, elitist, consumerist-landfilling, and "just because its vintage makes it $$$" cultural mentalities of the Los Angeles region, and you'll see why doing this sort of thing on the cheap is such a challenge.

Haven't been to Murphy yet. Its a bit of a drive, and I have to see if they're open on Sundays, which is usually the only days I'm able to be down that way...

Apex I've been to many times... like most gold mines, the gold is buried!

73,
Jason kf6pqt

 :)

Burbank isn't a good place for antennas unless you have a palm tree in the yard and you might get up a dipole for 40m. Then it is shaded by the little old lady mountain of pasadena.

The short "long wire" antenna runs directly overhead of some phone lines, and just far enough away from the AC mains to safely clear 'em if it fell. Assuming the wind isn't blowing hard to the west. ;)

Little 20m inverted V on the roof, held up by 14' of 1 1/2" PVC. Hopefully a trap-vertical goes up this weekend on the fenceline.

Leaving Southern California isn't an option, despite the challenges! ;)

-Jason