TNC-X

Introduction

All you need to use email, without having a local internet connection: laptop with Winlink installed, TRX (with antenna) and TNC-X.

All you need to use email, without having a local internet connection: laptop with Winlink installed, TRX (with antenna) and TNC-X.

The Dutch Amateur Radio Emergency Service (DARES) is currently setting up a messaging system for emergency communications. Email is sent over radio using the good old AX.25 protocol. Part of this project is the TNC-X, a simple packet radio modem with a USB interface. I am trying to get rid of those RS-232 boxes, so having a TNC with a USB interface is one more step in that direction. Hans PA3GJM managed to get lots of radio amateurs together to buy 100 TNC-X modems. I was one of them.

More info on the TNC-X can be found on this website: www.tnc-x.com. — more →

HEDZ antenna for 80 and 160m

Introduction

The HEDZ for 80m and 160m requires 3 poles A, B and C. Pole B is 15m tall, A and C are 9m. The distance from A to C is over 100m.

The HEDZ for 80m and 160m requires 3 poles A, B and C. Pole B is 15m tall, A and C are 9m. The distance from A to C is over 100m.

The zeppelin antenna (or simply “zepp”) is a popular end-fed wire antenna for shortwave bands and has lots of simularities with the J-pole antenna. It consists of a long wire (half wave length), connected to one of the wires of a balanced feedline (quarter wave length). The idea is that the end of the wire has a high impedance, and the quarter wave transmission line transforms this to a low impedance, at least low enough to get to 50 ohms using a balanced tuner. A Double Zepp is a normal zepp, but the other (unconnected) wire of the feeder is also connected to a second wire. The Extended Double Zepp (EDZ, sometimes also known as Double Extended Zepp or DEZ) is the same, but the wires are now 5/8 wavelength instead of 1/2. The tricky part of this antenna is now the length of the feeder. Paul N8ITF gives you the measures for all versions of the EDZ. — more →