On 2019-10-11 3:19 PM, Doug Person wrote:
>
My favorite is the "Differential-T" 986 which tunes everything with
very little effort.
Any of the many "T" (single shunt coil, multiple series capacitors)
network tuners are high pass networks. They do very little to
suppress harmonics and/or phase noise above the transmit frequency.
73,
... Joe, W4TV
On 2019-10-11 3:19 PM, Doug Person wrote:
Is there any modern-day equivalent to the old Johnson Matchbox? I use
several different MFJ tuners with good results. My favorite is the
"Differential-T" 986 which tunes everything with very little effort. I
don't actually know how efficient it is but it tunes my 132' doublet fed
with 450 ohm ladder line very well. I use the antenna mostly on
160-80-60-40-30 where it seems to perform well. The ladder-line comes to
a 1:1 high power balun just outside the shack and 10' of rg213 comes
inside to the tuner. The only interesting observation is that it seems
noisier than my multi-band trapped dipole - as much as 1-2 s units
sometimes. Otherwise, if I only had one antenna it would be the doublet.
Very versatile. The tuner gives the rig a good under 1.5:1 match 160
through 6.
73, Doug -- KJØF
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