[Elecraft] 160 meter low transmit
Don Clark
kes4845 at cox.net
Fri Aug 26 02:21:50 EDT 2005
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
----- Original Message -----
From: "W3FPR - Don Wilhelm" <w3fpr at earthlink.net>
To: "Don Clark" <kes4845 at cox.net>; <elecraft at mailman.qth.net>
Sent: Thursday, August 25, 2005 11:43 PM
Subject: RE: [Elecraft] 160 meter low transmit
> Don,
>
> It would appear that you may have something wrong in the 160 meter low
pass
> filter. Count the turns on the toroids, and check the capacitors for the
> correct values.
>
> You are measuring the power output with a good 50 ohm dummy load, are you
> not? If you are attempting to feed an antenna, the power output may be
> real, but the problem is the feedpoint impedance of the antenna and not
the
> K2.
>
> Please povide ua with more information of what does and does not work, if
we
> are to offer more specific assistance.
>
> 73,
> Don W3FPR
>
> > -----Original Message-----
> >
> > I built and installed the 160 meter module in 2000, but didn't
> > align 160 meters since I didn't have an antenna at the time. I
> > have recently completed my KPA100 and before closing up the rig,
> > I decided to align 160. I receive signals on 160, but can't get
> > more than 1.4 watts out, even when setting the power to 10 watts.
> > I have resoldered all the components on the module board and the
> > RF board. I believe that my toroids are connected ok. I have
> > full output on 80 meters.
> >
> > Don - KA6AKH
> >
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