Re [1000mp] Ameritron QSK-5

[tony canning]

Pete, my QSK-5 works quite well however there was major drawback with it.=

In that after you key up (go back to RX) there is a short delay before th=
e
relays in the QSK box and the amp switch over. What this means is that yo=
u
get some of the exchange and then a loud click as the relays change over.=

Clearly this depends on how fast the other operator is sending > 25WPM is=

just about ok in contests but very annoying, but if its a long exchange i=
ts
hopeless. There are two relays in the amp and two in the QSK-5.

The sound of these relays going over can be disconcerting as is causes
significant noise with the 500/250Hz filters (Yaesu) in cct. =


To reduce the effects of this I changed the dwell time in the QSK-5 after=

key-up, and have fitted a front panel pot on which varies this time from =
3
to 30 seconds. Although you need to remember the amp will be in standby f=
or
this additional time ie 90mA on my old FL2100Z (400W) resulting extra
heating.

On the Control/Psu board I changed R8 from a fixed value of 3.3K to 100K
lin Pot. The variable delay time is much more useful as you can then
determine the best delay for your style of operating. Transistor Q1 a
2n3906 is used to drive the relays will also have some affect on the time=

particular if the gain is low and also any leakage current in C5 (100uF)
which forms part of the timing cct.

I can run my MP with full break in at 30WPM no problems but prefer semi
break-in with a short keying delay on the menu.
I have had 700W through the switch without problems but at >1kw and/or
>1.5:1 VSWR the main PIN diodes could overheat.
The power upgrade on offer from MFJ is just a bolt on external fan!

The hand book (without ccts) is on the MFJ web site and may be of some
help.
The QSK-5 board/s can be incorporated within some amplifiers and the hand=

book gives info for some Ameritron amps.

The use of the QSK box as its a great improvement when using older style
amplifiers without built in PIN diode switches.

HNY =

Tony G0opb