Elecraft

(KX1) - Question of Power Modification Timing

Classic

List

Threaded

3 messages Options

stan levandowski

(KX1) - Question of Power Modification Timing

I'm building my second fully optioned KX1. I built one a few years ago
with no problem and it was great. I sold it when I bought a KX3. I
missed it so much I just bought myself another one.

But I could use some advice because something doesn't make sense to me.

I opened the 30/80 meter parts package and found a "Power Output
Modification Kit" for the KX1. It consists of two resistors:
replacements for R11 and R30.

I have not yet installed the "original R11 and R30" so can I just
install these power mod resistors NOW to avoid future de-soldering?

This sounds like a dumb question, I know, but it seems that if this has
been a known problem for the KX1 since April 2006 (Revision B), why
weren't the kit resistors upgraded a long time ago, or made an addendum
to the KX1.

Why were they in the 30/80 module kit? What's the connection? Do the
upgrade resistors only apply to the 30/80 mod?

If I had not ordered the 30/80 mod, I would not have known about this
power mod.

73, Stan WB2LQF

______________________________________________________________
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
Message delivered to [hidden email]

Don Wilhelm

Re: (KX1) - Question of Power Modification Timing

Stan,

The information in the Power Mod instructions is correct. SOME KX1s
have lower power output than others due to component tolerances. Ni
some cases, this becomes more of a problem with the KXB3080
installation. I would not arbitrarily install those resistors.

Install the KXB3080 option and then test all bands using a 13.8 volt
power source. If you can achieve 3.5 watts on all bands, that is all
the design point offers. If one or two bands are lower, first try
adjusting the spacing of the green turns on L1 and L2 to see if you can
even out the power.

If you cannot achieve 3.5 watts on any band, then install the power mod.

I must add that the heatsinking of the KX1 and the rating of the zener
diode in the PA stage are not designed for more than 5 watts. If you
are getting more than 5 watts on any band, turn R1 to a lower level to
limit the power to 5 watts.

If you will always be operating on a voltage less than 13.8 volts
(battery operation), you may want to install the power mod anyway.
The actual power output will depend on the power supply voltage.

73,
Don W3FPR

On 12/18/2016 6:12 PM, stan levandowski wrote:

> I'm building my second fully optioned KX1. I built one a few years ago
> with no problem and it was great. I sold it when I bought a KX3. I
> missed it so much I just bought myself another one.
>
> But I could use some advice because something doesn't make sense to me.
>
>
> I opened the 30/80 meter parts package and found a "Power Output
> Modification Kit" for the KX1. It consists of two resistors:
> replacements for R11 and R30.
>
>
> I have not yet installed the "original R11 and R30" so can I just
> install these power mod resistors NOW to avoid future de-soldering?
>
>
> This sounds like a dumb question, I know, but it seems that if this has
> been a known problem for the KX1 since April 2006 (Revision B), why
> weren't the kit resistors upgraded a long time ago, or made an addendum
> to the KX1.
>
>
> Why were they in the 30/80 module kit? What's the connection? Do the
> upgrade resistors only apply to the 30/80 mod?
>
>
> If I had not ordered the 30/80 mod, I would not have known about this
> power mod.
>
>
> 73, Stan WB2LQF
>
>
>
>
>
>
> ______________________________________________________________
> 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
> Message delivered to [hidden email]

______________________________________________________________
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
Message delivered to [hidden email]

stan levandowski

Re: (KX1) - Question of Power Modification Timing

Don thank you for this rapid and complete answer. I'm printing this
email out to include with the KX1 documentation. I'll always be using
either the internal AA cells or a dedicated 12VDC wall wart so I think
I'll just install the mod now and avoid de-soldering.

73 and Seasons' greetings,
Stan WB2LQF

On Sun, Dec 18, 2016 at 06:35 PM, Don Wilhelm wrote:

> Stan,
>
> The information in the Power Mod instructions is correct. SOME KX1s
> have lower power output than others due to component tolerances. Ni
> some cases, this becomes more of a problem with the KXB3080
> installation. I would not arbitrarily install those resistors.
>
> Install the KXB3080 option and then test all bands using a 13.8 volt
> power source. If you can achieve 3.5 watts on all bands, that is all
> the design point offers. If one or two bands are lower, first try
> adjusting the spacing of the green turns on L1 and L2 to see if you
> can even out the power.
>
> If you cannot achieve 3.5 watts on any band, then install the power
> mod.
>
> I must add that the heatsinking of the KX1 and the rating of the zener
> diode in the PA stage are not designed for more than 5 watts. If you
> are getting more than 5 watts on any band, turn R1 to a lower level to
> limit the power to 5 watts.
>
> If you will always be operating on a voltage less than 13.8 volts
> (battery operation), you may want to install the power mod anyway.
> The actual power output will depend on the power supply voltage.
>
> 73,
> Don W3FPR
>
> On 12/18/2016 6:12 PM, stan levandowski wrote:
>> I'm building my second fully optioned KX1. I built one a few years
>> ago
>> with no problem and it was great. I sold it when I bought a KX3. I
>> missed it so much I just bought myself another one.
>>
>> But I could use some advice because something doesn't make sense to
>> me.
>>
>>
>> I opened the 30/80 meter parts package and found a "Power Output
>> Modification Kit" for the KX1. It consists of two resistors:
>> replacements for R11 and R30.
>>
>>
>> I have not yet installed the "original R11 and R30" so can I just
>> install these power mod resistors NOW to avoid future de-soldering?
>>
>>
>> This sounds like a dumb question, I know, but it seems that if this
>> has
>> been a known problem for the KX1 since April 2006 (Revision B), why
>> weren't the kit resistors upgraded a long time ago, or made an
>> addendum
>> to the KX1.
>>
>>
>> Why were they in the 30/80 module kit? What's the connection? Do the
>> upgrade resistors only apply to the 30/80 mod?
>>
>>
>> If I had not ordered the 30/80 mod, I would not have known about this
>> power mod.
>>
>>
>> 73, Stan WB2LQF
>>
>>
>>
>>
>>
>>
>> ______________________________________________________________
>> 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
>> Message delivered to [hidden email]
>