[Elecraft] K2 trouble on 160M

[Don Wilhelm]

Bill,

Since it misbehaves with the dummy load, you will most likely find the 
problem in the base K2 160 meter Low Pass Filter.
I am surprised that you do not also see Hi Curr messages.

73,
Don W3FPR

NZ0T wrote:
> Thanks Don,
>
> The rig behaves the same into the dummy load in all configurations with or
> without the KAT100 in line, with or without the mike or paddles connected,
> with or without attached and I even tried a different coax jumper.  160 is
> the only band it occurs on.  What is confounding me is that it workrd fine
> at home but not here with the exact same configuration.
>
>
>
> Don Wilhelm-4 wrote:
>   
>> Bill,
>>
>> What does that K2 do when working into a dummy load?  If it still fails, 
>> the problem is definitely with the K2.  If it behaves, then you need to 
>> look at your antenna system - you may be better off with a 1:1 choke 
>> balun than your 4-1 balun.  I really don't know why hams persist in 
>> using a 4-1 balun when driving ladder wire feeders - the 450 ohms is 
>> only the characteristic impedance of the line and that says nothing 
>> about the feedpoint impedance - the ladder line acts as a transmission 
>> line transformer.  Measure the feedpoint impedance of the 450 ohm line 
>> with an antenna analyzer (operate it on batteries) where you connect the 
>> balun.  If the impedance is high, then use the 4-1 balun, but if it is 
>> low a 1-1 choke balun will be a better choice.  Which balun is better 
>> depends on the electrical length of your feedline.
>>
>> The K2 can behave differently in the presence of RF-in-the-shack than 
>> your 706, so that is not a fair comparison.  Look at what you have 
>> connected to the K2 and ask what is different - the routing of the 
>> paddle cable?  How is the power supply cable routed? Do you have a 
>> microphone connected?  Have you grounded the microphone jack shell on 
>> that K2?
>>
>> If you have a K2 problem, ask again with details of the failure with a 
>> dummy load.  Get it working with a dummy load before adding the extra 
>> element of the antenna into the problem.  All we can say right now is 
>> that your problem is either with the antenna, power supply, any cable 
>> attached to the K2 or the K3 itself.  Which one is pure guesswork until 
>> you reduce the number of variables.
>>
>> 73,
>> Don W3FPR
>>
>> NZ0T wrote:
>>     
>>> Now that I have my K3 at home I moved my K2/100/KAT100 to our lake cabin. 
>>> Last weekend it started to shut down on 160 only when transmitting over
>>> about 70 watts.  All other bands are fine, the antenna (160M dipole fed
>>> with
>>> ladder line thru 4-1 balun and about 6' of coax into the cabin) is fine
>>> and
>>> the ground  seems fine.  It was shutting down the MFJ 4125 switching
>>> power
>>> supply so thinking maybe RF was getting into the supply I took the rig
>>> home
>>> and it worked just fine there.  Brought it back this weekend with an
>>> Astron
>>> linear supply and while that PS is not shutting down the rig still wants
>>> to. 
>>> I have used this same setup before here with no problems and this started
>>> happening suddenly last weekend.  I tried the rig without the KAT100 thru
>>> a
>>> manual tuner and it still wants to shut down.  My Icom 706 works fine on
>>> 160
>>> with the same configuration.
>>> Ideas?
>>>
>>> 73,
>>>
>>> Bill NZ0T
>>>   
>>>       
>