Problems with K2 #4502 ??

[Fred Bennett N9TA]

    Hi Gang

I just completed my 2nd K2......I sold the first one (#242) a couple
of years ago. The new K2  (#4502) was completed this morning.
This K2 was built with the KAT2, KIO2, KSB2, K160RX, and KBT2
options.

I seem to have rather low power output......at least I remember the
last K2 I built seemed to have higher output than this one.....might
I have a problem somewhere??? I tried the alignment both with and
without the ATU installed.....so I know the ATU is not the culprit.
These power readings were obtained into a dummy load and measured
with the same digital wattmeter I used with the last K2.

  160M.....13 watts
    80M.....14.13 watts
    40M.....12.8 watts
    30M.....13.26 watts    
    20M.....13.1 watts
    17M.....12.6 watts
    15M.....11.0 watts
    12M.....10.4 watts
    10M.....7.74 watts

Also, I may have wasted my money on the battery option. The
instructions for the battery option say to charge the battery from
a 14V +/- .2V.......I run my K2 from a solar charged battery setup.
At night with NO sun the system runs about 12.7V. During the
day with FULL sun it'll run about 13.7V. I had hoped to be able to
grab the K2, key, and portable antenna and head off into the woods
for an afternoon of play......but it looks like I'll have to charge the
battery from some other source. I kinda hate the thought of that!!
So far in it's life, K2 #4502 has had NO commercially produced
electrons inside it......seems like blasphemy to "plug it in"...HI HI

                 Any thoughts, ideas, comments???
                             73....de...Fred  N9TA
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[wayne burdick]

Hi Fred,

Power output varies from K2 to K2, but if you feel that it's low, Gary
can send you a list of things to check.

Regarding the solar-charging issue:

You can probably increase the output of the solar charger a bit. For
example if there's a diode in series, you can replace it with a 95SQ015
type, which has very low voltage drop. We should have them in stock
(send a request to [hidden email]). If the solar charger is
regulated, there may a voltage trimming adjustment. With no charge
regulator, the open-circuit voltage from a solar panel is generally
well above 13.7 V.

You can continue charging the K2's internal battery as long as the
voltage is at 14 V or higher, *or* if it's steadily *rising*,
indicating that the battery is pulling the voltage down as it charges.
A depleted battery may drag the solar panel down to 12 to 13V during
initial recharge, depending on how large a panel you have and how much
insolation is available. (It's 800 watts per square meter at the
equator in full sun, and you won't need that much  :)

Further details on solar charging can be found in back issues of QST,
on the web, and probably from the manufacturer of your panel.

73,
Wayne
N6KR

---

http://www.elecraft.com

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[Don Wilhelm-3]

Fred,

You do seem to have considerable max power dropoff on 10 and 12 meters.
Re-check T2 to be certain it is wound just like the figure in the manual.
It also helps to mount T2 about 1/8 inch above the board.

The second thing that can hold down max power is the CAL CUR setting - set
it higher and see if you get any additional output.  With a 13.8 volt
supply, power out of 15 watts on all bands except 12 and 10 meters is quite
common, and if the CAL CUR setting is moved to 4.5 amps, I have obtained as
much as 18 watts on some K2s  - the important thing is that you are able to
achieve at least 10 watts on all bands - that is the spec, anything above
that is additional joy.

As far as your Internal Battery charging, you do need 14.1 to 14.2 volts at
the K2 power jack to assure adequate charging (and batteries can have short
lifetimes if undercharged - or overcharged).  If you have a charge
controller included with your solar system, you may want to consider a
direct connection to the battery (you may have to install a second charge
controller).  For an example of how to do the direct connect with proper
safety considerations, take a look at the SmartCharger article on my webpage
www.qsl.net/w3fpr.

73,
Don W3FPR

----- Original Message -----
I just completed my 2nd K2......I sold the first one (#242) a couple
of years ago. The new K2  (#4502) was completed this morning.
This K2 was built with the KAT2, KIO2, KSB2, K160RX, and KBT2
options.

I seem to have rather low power output......at least I remember the
last K2 I built seemed to have higher output than this one.....might
I have a problem somewhere??? I tried the alignment both with and
without the ATU installed.....so I know the ATU is not the culprit.
These power readings were obtained into a dummy load and measured
with the same digital wattmeter I used with the last K2.

  160M.....13 watts
    80M.....14.13 watts
    40M.....12.8 watts
    30M.....13.26 watts
    20M.....13.1 watts
    17M.....12.6 watts
    15M.....11.0 watts
    12M.....10.4 watts
    10M.....7.74 watts

Also, I may have wasted my money on the battery option. The
instructions for the battery option say to charge the battery from
a 14V +/- .2V.......I run my K2 from a solar charged battery setup.
At night with NO sun the system runs about 12.7V. During the
day with FULL sun it'll run about 13.7V. I had hoped to be able to
grab the K2, key, and portable antenna and head off into the woods
for an afternoon of play......but it looks like I'll have to charge the
battery from some other source. I kinda hate the thought of that!!
So far in it's life, K2 #4502 has had NO commercially produced
electrons inside it......seems like blasphemy to "plug it in"...HI HI



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