MFJ 1026 mkII by I7SWX
* * * Noise Cancelling Tricks * * *
mods added sett.2012 read pdf below.
english translation gen.19
This mod has seen the light because the noise antenna used, to phaseout a strong local noise
is very close to the transmitting antenna
and I wanted to add a simple device that disconnected the Noise Amplifier input as further protection..
The schematic is very simple, as shown in the larger pic at the below link I have added a switching pnp transistor bc556, a diode 1n4148,
a 12V relay dual-pole, a led has been added mainly for cosmetic purposes and gluing it near the noise preamp switch hole.
link to larger pic. The green wire in the pic goes to a panel-led to show its state during transmission.
The pic below shows the on off tests on 160meters as viewed on my RF panoramic balcony via the SDR_Radio program.
Finding the best noise antenna type is a matter of trying various combinations around your property in order to discover
which wire and its lenght is better for you case.
Sometime ago speaking with my friend Gian I7SWX about possible improvements of the Noise Canceller I sent him my unit.
After a couple of months he returned the NC unit which had modified\improved some essential aspects like better NULLING and PHASING.
The following link to the pdf file (italian only at the present) MFJ1026 noise canceller mods by I7SWX and IZ7ANL sett.2012
gives the first impressions of use, more informations will be written in a further file.
here is the link to the translated document in english by George W9ZSJ
mag.2012, info feb2016, english gen.2019