[Elecraft] Center-fed antennas

[Joe Subich, W4TV]

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
>