[R-390] the saga cont. pt 10

[ka9egw at britewerkz.com]

I'm sure it's the primary winding is wound in 2 pies over the secondary,
right?  The inside winding done as a single solenoid has 3 silver mica's on
it whose values match the ones on the secondary on the shcematic in
TM11-856A and TM-11-5820-358-35.

The wire goes from the pin, to the trimmer, through the frame, a couple
turns on one pie, back out, along the frame, back in through the frame, the
other pie, and back to one of the little radial-leaded cylindrical fixed
caps [I think that's what it is] thence to the other pin.  Seems to me if
that center tap is supposed to be grounded, where that wire runs over that
frame member is the only place it could be done, but it is apparent neither
of them has ever been soldered there.  The Teledyne can does show what looks
like it might have been fluxed there at one point, but solder, no.  Plus it
looks like magnet wire [enameled].

73, Brian KA9EGW

-----Original Message-----
From: Craig C Heaton [mailto:wd8kdg at att.net]
Sent: Sunday, September 26, 2010 4:12 PM
To: ka9egw at britewerkz.com; r-390 at mailman.qth.net
Subject: RE: [R-390] the saga cont. pt 10


Brian,

On all the racks, I've left the antenna trim at "0". Peaked n' tweaked as if
it is a 50 ohm input receiver. The reason is my R-390A's are paired with
transmitters and the antenna tuner/transmission line/ antenna is adjusted
for 50 ohms to keep the transmitter happy.

Hopefully, with the receiver aligned this way, "0" on the antenna trim
should be the peak reading (it is on mine) on the carrier meter when the
antenna system is adjusted for the transmitter. YMMV.

Craig,



-----Original Message-----
From: r-390-bounces at mailman.qth.net [mailto:r-390-bounces at mailman.qth.net]
On Behalf Of ka9egw at britewerkz.com
Sent: Sunday, September 26, 2010 2:03 PM
To: r-390 at mailman.qth.net
Subject: [R-390] the saga cont. pt 10

Doing the RF alignment.  Working from the idea this thing may have been
over-diddled at some point.  Almost every adjustment so far has required
multiple turns of slug or significant movement of the cap to dial things in.
All well and good til the top band, [16-32] Mc cans.  The way this ckt is
put together, do you all think the antenna trim control should have much
effect when using the balanced input, or is it simply coincidental that on
the other bands it does?
I swapped in a different can from my spare RF deck, and same deal...
73, Brian KA9EGW

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