Posted by
Bill Frantz on
Apr 02, 2017; 2:35am
URL: http://elecraft.85.s1.nabble.com/Antenna-Problems-with-K3-firmware-5-57-tp7628786p7628845.html
On 4/1/17 at 6:44 AM,
[hidden email] (Dick Bacon via
Elecraft) wrote:
>... that was to check and tighten the three screws on the bottom cover
>for the LPA transistors (p63 in assembly manual).
I got the same advice, but mine were quite tight. If you have
problems with erratic SWR or Power readings, check those screws
before sending an email to support. :-)
An update on the broadcast station interference problem aka the
antenna problem.
I looked at KLIV's data in the FCC database (thanks Jim K9YC for
the links). It turns out that after sundown, KLIV changes the
pattern of its antennas to put most of the power directly toward
my QTH.
<
https://transition.fcc.gov/Bureaus/MB/Databases/AM_DA_patterns/429300-67110.pdf>.
No wonder I have a problem.
Jack, W6FB wondered how long a coax stub for 1590 KHz would be.
A quick back of the envelope calculation came up with a bit more
than 100 feet. I pulled out a piece of RG-58 labeled 104' and
hooked it up as a stub. The problem get a lot better, but it had
a noticeable effect on the bottom end of the 160M band. The stub
is far from being a notch filter.
Adding another piece of coax got it below the 160M band, but I
worry about suppression of odd harmonics at higher frequencies.
I think I have used the antenna for QSOs on every amateur band
from 160M to 6M inclusive. So on to something that took longer
than 10 minutes to try.
I dug through the junk box and found a 560 pF 1KV cap and a
T68-2 core. Quality time with the ARRL Handbook said to use 56
turns on the core, which I did with some #30 wire. So far, knock
on wood, this seems to get proper power output on the entire
160M band. And the core only gets warm if you hold the key down
for a long time. I'll need thicker wire before the next 160M
RTTY contest.
73 Bill AE6JV
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Bill Frantz | Security is like Government | Periwinkle
(408)356-8506 | services. The market doesn't | 16345
Englewood Ave
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CA 95032
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