Anyone using the ZM4 tuner ?

[TK5EP]

Hi all,

Is anybody using the ZM4 tuner for SOTA operation ?
I want to build a small simple tuner and this one seems fine.

Thanks for your advices,

73 Patrick TK5EP

[DH8WN]

Hi Patrick,

I’m using a ZM4 for around 6 years, most for SOTA. Do you build the tuner from the kit available from www.qrpproject.de/ ?

73, Ludwig

[DL6GCA]

I had bought the ZM4 tuner as a kit and built it up as lockdown project. It works really well.

Lockdown Projects

My latest lockdown project was adding a fan to the linear power supply in my shack. When I did a long run of CW QSO’s at 100W, a strange smell started coming from under my desk … in case you readers have any doubt, the smell came from the PS ! I found a very simple circuit here I took a 10k NTC resistor (there is one in every laptop battery pack, they look like two thin wires with a “drop” of plastic at the end), and a 10k multiturn trimmer (not 50k). The FET used was an IRF830, but…

Since I have tuned antennas for the QCX and otherwise the tuner is installed in the KX2, I sold it.

In the QRPshop you don’t get him to my knowledge any more… The store ends soon.

It is in any case a good working tuner.

73 Armin

[ON7DQ]

Hi Patrick:
I think Armin wanted to send you to this link

Lockdown Projects

My project It has always appealed to me to have a transceiver with as few components as possible and also to participate in the qrp-minimal-art-session. …as a SOTA - activator. Unfortunately, I am not in the mood to develop something like this myself. But there are kits. My cw-trx has 89 components (without housing). The coil winding is particularly tricky. And while I was at it, I also built the antenna tuner. [IMG_3236] [IMG_3237] [IMG_3239] 73 Armin

It was this post that inspired me to build a ZM-4 clone myself, I have a full description on my blog

My version of a Z-match Tuner

There are links to the original ZM-2, and the ZM-4 manual with circuit diagram.

Luc ON7DQ

[VK3AFW]

Patrick,
Have you considered the AT100 kit?
73
Ron
VK3AFW

[TK5EP]

Ron, I have a AT100 (older version without latching relays)
But for SOTA and the type of antennas used, it’s not adequate.

73 Patrick

[TK5EP]

Thanks to all who replied,

Meanwhile, I swept the SOTA reflector and found the KX0R build.
Now I have to check which design is the most versatile.

I have almost all parts, so no need to buy a kit.

73 Patrick TK5EP

[TK5EP]

Hi Ludwig,
What sort of antennas and bands do you tune with this ZM4 ?

73 & thanks
Patrick

[DH8WN]

Hi Patrick,

so far as I remember:

• 6,5 m vertical wire with one “radial”, on 40 m, 20 m, 15 m, (10 m and bands between)
• OCF Dipole on 40 m, 20 m and 15 m, SWR below 2, also used on 80 m (dipole to short)
• “random” wire, end feed, about 15 m long, on different bands 80 m … 15 m
• dipole 40 m long on 80 m (HW) and 40 m (FW)
• 9,x m vertical wire and two radials, on 40 m, not exact tuned

73, Ludwig