[Elecraft] 160 meter low transmit

[Don Clark]

One additional note.  An additional note.  When I tune on 160m, then tune on
80m, I get a Hi Cur on 80 m.  If I turn the tune off on 80 then retune on 80
I get no Hi Cur.  I do not get a hi Cur on 160 after tuning on 80m.

Don

----- Original Message ----- 
From: "Don Clark" <kes4845 at cox.net>
To: <w3fpr at arrl.net>; <elecraft at mailman.qth.net>
Sent: Friday, August 26, 2005 2:29 PM
Subject: Re: [Elecraft] 160 meter low transmit


> Don,
>
> I pulled C13, 14 last night and both were 1300 pf on my meter.
>
> I used the RF probe I contructed from the K2 Elecraft kit parts in 2000.
>
>                                                Voltage
> Component                   80m                      160m
>
> D6                                40.7 mv                57.2 mv
> D7                                40.9 mv                57.8 mv
> W6                               21.6 mv                13.4 mv
> Q5                               298  mv                  0
> Q6                              1.8 volts                 .9 volts
>
> Don - KA6AKH
>
>
> ----- Original Message ----- 
> From: "W3FPR - Don Wilhelm" <w3fpr at earthlink.net>
> To: "Don Clark" <kes4845 at cox.net>; <elecraft at mailman.qth.net>
> Sent: Friday, August 26, 2005 7:42 AM
> Subject: RE: [Elecraft] 160 meter low transmit
>
>
> > Don,
> >
> > With that information, I would suspect the bandpass filter (even if it
> > receives 160 meters fine) - re-check C13 and C14 for the correct value
of
> > 1200 pf.
> >
> > If that does not correct things, use an RF probe or 'scope and compare
RF
> > Voltages between 160 meters and 80 meters with the power set at about 5
> > watts.  Check at the following points (you can stop at the first one
that
> is
> > substantially lower on 160) - cathode of D6 or D7 first - then at jumper
> > W6 - then the collector (case) of Q5 - next the collector (tab) of Q6 -
> then
> > the collector of Q7 and collector of Q8.
> >
> > Let us know where the 160 meter RF is being lost (RF Voltage
> substantiallly
> > less than that on 80 meters) and we can likely home in on the problem
> area.
> >
> > 73,
> > Don W3FPR
> >
> > > -----Original Message-----
> > >
> > > My K2 is serial 1683.  I built it in 2000.  With my initial kit,
> > > I added the
> > > SSB capability and the 160 capability; however, since I didn't have a
> 160
> > > antenna then, I didn't complete the 160 alignment.  I built the
> > > KPA100 over
> > > the weekend and before closing up the rig, I decided to align 160.
When
> > > applying the 2 watts via the power dial and adjusting L3 and L4, I can
> get
> > > no more than 1.3 to 1.4 watts out.  I do receive 160 signals, and well
> at
> > > that.  I compared my K2 to my FT-1000D and the K2 signal is received
> more
> > > strongly.  I first reheated all the solder points including those
> > > mods that
> > > were done to the RF board for the 160 capability and the pin
> > > connectors, but
> > > no increase in power.  I demounted the toroids on the module,
> > > retinned them
> > > and put them back, but still no increase in power.  I tested the
> > > toroids for
> > > continutity on the tinned elements before remounting them, and they
> tested
> > > fine.
> > >
> > > I measure 1.3 to 3 volts at R30 from 1800 to 2000.  I connected a
> > > dummy load
> > > in front of the LPF and get the 1.2 watts there.   Adjusting the
> > > power knob
> > > doesn't change the output at all.  I took apart the LPF and
> > > tested each Cap
> > > and values are fine.  L5 is the correct value.  I pulled and test
> > > C75, C13,
> > > and C14, all ok.  All the Caps in the pre-driver, driver and power amp
> are
> > > all the correct values.  The only one I couldn't check is the one
> between
> > > the 2 power transistors on the bottom of the board.
> > >
> > > The resistance of my relay coils meets the specifications.
> > >
> > > I checked the T4 as noted in the notes on 160 issues on the Elecraft
> > > website, and mine is to spec with the 3 windings for points 3 and
> > > 4.  My kit
> > > didn't have the 39 pf cap for one near U5.  It has a 68 pf.
> > >
> > > I am outputting the K2 to a dummy load during my transmit tests.  My
> power
> > > supply is outputting 13.8 volts.
> > >
> > > Don - KA6AKH
> > >
> > --
> > No virus found in this outgoing message.
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> > Version: 7.0.344 / Virus Database: 267.10.15/81 - Release Date:
8/24/2005
> >
>