On 7/22/2024 6:41 PM, Jim Brown wrote:
Both the trap and the loading coils are pretty easy to build if we
have good data and/or construction details.
The trap is nothing special. Since it connects to the tower at the
top, it is likely resonant on 40 meters - in fact the parts list
in the MK-160A manual online shows: p/n 977234 Trap, 40 meter
This is the same 40 M trap used in both the Hy-Gain DP-5BDQ
(80/40/20/15/10 trapped dipole) and DP-2BDQ (80/40 trapped dipole).
The loading coil is also nothing special ... 4 turns per inch, 3" ID x
10" long (per the LC-160Q Product Manual online). Originally, it was
B & W coil stock - I presume it was being made by MFJ recently.
Both approaches have significant problems:
The trap results in an inverted L that is only 25 high - very low
efficiency. The loading coil (at high power) results in high
voltage across the insulator at the bottom of the "whip" which
is a weak point (and will melt down!).
73,
... Joe, W4TV
On 7/22/2024 6:41 PM, Jim Brown wrote:
On 7/22/2024 1:47 PM, browndog2344@gmail.com wrote:
I see that MFJ (current owner of HyGain) still has MK-160A's for sale
(~$200).
Both the trap and the loading coils are pretty easy to build if we have
good data and/or construction details. Hopefully, someone can document
them well and share the data.
73, Jim K9YC
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