[Elecraft] KX1 ATU causes power to drop off...

[Don Wilhelm]

Chuck,

That is progress, but for the life of me, I cannot think of any way the 
KXAT1 would cause the power to gradually decrease.  It is getting late 
for me today, so I will sleep on it and see if anything pops into my 
head in the morning.

One thought that does occur to me is that there may be a bad solder 
connection somewhere in the KXAT1.

73,
Don W3FPR

On 6/4/2012 10:04 PM, hawley, charles j jr wrote:
> Yes. E was not going low and F not turning on the relay.
> The power out on 80M is 4 watts now. The other bands
> are around 3.6 to 3.8 watts.
> I still have the tuner in reduces the power out on
> all bands and drops to less than a watt.
> When I push on the LPF board, the power goes down...
> and the ATU does that with a relay.
> So that's my problem. I'll check why.
> Thankyou so much, I would have been going in circles without
> the LPF relay tip.
>
> Chuck, KE9UW
> aka Jack, BMW Motorcycles BMWMOA #224
>
> ________________________________________
> From: Don Wilhelm [w3fpr at embarqmail.com]
> Sent: Monday, June 04, 2012 7:44 PM
> To: hawley, charles j jr
> Cc: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] KX1 ATU causes power to drop off...
>
> Chuck,
>
> Look at the Low Pass Filter.
> The PA transistor cannot really go to 10 watts output - I suspect the
> relay on the LPF board is not being activated on 80 meters and is
> allowing a low of 2nd and 3rd harmonic energy get through.  A 'scope
> would show that, but for some reason or another, that makes the 80 meter
> output look like 10 watts of power on a wattmeter.
>
> Once you get the Low Pass Filter working correctly on all bands, try the
> KXAT1 again and if the power falls off - I don't think that is a related
> problem.
>
> 73,
> Don W3FPR
>
> On 6/4/2012 6:43 PM, ke9uw wrote:
>> I just finished the KX1 kit and without the tuner, power output into a 50 ohm
>> load is about 10W on 80M, and 4W on 40M, 30M, and 20M using a Bird meter,
>> 50W slug.
>> However the ATU which seems to work well in all testing, all the relays
>> click, etc., in TUNE the power starts out at a reading of about 3 watts (40,
>> 30, 20...a watt higher on 80) and falls off in about 2 to 3 seconds to about
>> .5 watts. The Bird meter shows exactly the same power fall off.
>> Also the SWR reading in all cases reads 1.0 using the dummy load. So it
>> seems like something is heating up (don't feel any heat anywhere) and the
>> power falls off...but it still always reads an SWR of 1.0 when I go out of
>> TUNE.
>> When I remove the ATU and install the jumper the power is steady for all
>> bands (just higher on 80M).
>>
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