Urban SM5EUF wrote:
Measuring the coil Q revealed that having the coil elevated
about 70cm above the floor (concrete) resulted in a Q of 300
and when putting the coil directly on the floor with the lowest
turn about 5cm above the floor the Q was reduced to 220. The
first 30 cm seemed to make a big difference. From 30 up to
70cm did not make much change . . . . Having seen on homepages
that some of you have the coil standing quite close to ground it
might be wise to elevate it somewhat.
Thank you, Urban, for your observations. The base of my loading
coil is only about 15 cm above ground. So it seems that I should
be able to make some improvements when I rebuild the loading coil
later this year.
By the way, as at G3KEV, I have also designed all my equipment to
match to 50 ohms, and tune for minimum SWR. I find that
continuous monitoring of SWR provides a very sensitive indication
of what's happening at the hot end.
Regards to all,
Steve GW4ALG
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