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KXAT1 - No RF Power on display

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K Price

KXAT1 - No RF Power on display

Just completed building the KXAT1. I believe I successfully passed each alignment step.

1) No "---" when selecting ATU
2) Hear relays switching as I move through L0, L1, ... N1, N2
3) Adjust C9 until a dc volt value of 0.01 on the meter.
4) When I "tune" into a dummy load or a descent antenna (e.g. Alpha Delta
DX-EE), I hear the relays clicking and get an r of 1.2 or so.

However, I don't get any RF reading on the display when transmitting. To check
that I was really getting out, I hooked up my W1 meter and it shows
about 1 watt of power out using 12 volts from my power supply.

Any thoughts about why I wouldn't see anything on the display?

Thanks,

Keith - WA5LPW
www.wa5lpw.com
901.409.1432
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Don Wilhelm-4

Re: KXAT1 - No RF Power on display

Keith,

When transmitting (tuner installed or not), the KX1 displays bars on the
LED that are proportional to the power output - approximately 1 bar per
watt. With the tuner installed, it displays the power after tuning -
then tap any button and the display briefly shows the SWR achieved.
That is normal indication.

Your balance point should be lower than 0.01 volts - move the trimmer
VERY slowly and you should be able to achieve 0.001 volts or lower.

If you are getting only 1 watt out with a 12 volt supply, you may have
some other problem with the KX1. First thing to check is the LPF
toroids (L1 and L2) - if they have an extra turn, that will cause severe
power output reduction.

73,
Don W3FPR

On 9/4/2011 3:11 PM, K Price wrote:

> Just completed building the KXAT1. I believe I successfully passed each alignment step.
>
> 1) No "---" when selecting ATU
> 2) Hear relays switching as I move through L0, L1, ... N1, N2
> 3) Adjust C9 until a dc volt value of 0.01 on the meter.
> 4) When I "tune" into a dummy load or a descent antenna (e.g. Alpha Delta
> DX-EE), I hear the relays clicking and get an r of 1.2 or so.
>
> However, I don't get any RF reading on the display when transmitting. To check
> that I was really getting out, I hooked up my W1 meter and it shows
> about 1 watt of power out using 12 volts from my power supply.
>
> Any thoughts about why I wouldn't see anything on the display?
>
> Thanks,
>
>
> Keith - WA5LPW
> www.wa5lpw.com
> 901.409.1432
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

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K Price

Re: KXAT1 - No RF Power on display

Don,
Thanks for the tips. I haven't tried to get a lower volt yet but will do that next. I did re-count L1 & L2 and both are correct. I also tried something new. With the back cover OFF, everything works better and get closer to 3 watts out. When I put the back cover ON, it drops to 1 watt and the display stops showing the power out graph.

Thoughts?

Keith, WA5LPW
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Don Wilhelm-4

Re: KXAT1 - No RF Power on display

Kevin,

That behavior is typical of a bad solder connection somewhere.
I suggest removing the KXAT1 and installing the jumper - now what is the
power output (you will have to use an external wattmeter) - operate it
into a 50 ohm dummy load to eliminate the variables that may be
introduced when operating into an antenna.

If the behavior continues when the back is put on, then the problem is
on the main board - OTOH, if all works as normal, the problem is in the
KXAT1.

73,
Don W3FPR

On 9/4/2011 9:12 PM, K Price wrote:

> Don,
> Thanks for the tips. I haven't tried to get a lower volt yet but will do that next. I did re-count L1& L2 and both are correct. I also tried something new. With the back cover OFF, everything works better and get closer to 3 watts out. When I put the back cover ON, it drops to 1 watt and the display stops showing the power out graph.
>
>
> Thoughts?
>
>
> Keith, WA5LPW
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

K Price

Re: KXAT1 - No RF Power on display

Great idea. I tested as you suggested and with the jumper in and the back cover on everything works normally. RF display = 1 bar. Wattmeter = 3 watts into a dummy load on 12 volts.

I will check all my solder connections on the KXAT board and post again.

Keith, WA5LPW
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