pa0nhc SWRsweeper V2

(C) The use, copy and modification of all info on this site is only permitted for non-commercial purposes, and
thereby explicitly mentioning my radio amateur call sign "PA0NHC" as the original writer / designer / photographer / publisher.

New version PCB #75 is available.

          The new #75 PCB is designed for :
1. Cheaper BNC chassis connector
2. Easier to solder AD8361ART6lead SOT-23

3. Wider pin holes in the main board for easier fit of the Arduino and DDS boards

Top copper of of PCB #75

The best location for the BNC bus, with its center
pin soldered to the PCB. The PCB is equipped
with large solder pads for BNC ground lugs.
The PCB could also with its sides be soldered
into a cheap box made of blank PCB material.

            Introduction  "SWR sweeper V2"  20170527   PCB #75 29170626
- Simple, accurate and fast (max. 5s) recognizing of the resonance frequency and the 50 Ohms math of antenna systems, filters and cables.
- Detection range and sweep range from 50kHz to 30MHz (70MHz max.).
- Can be connected directly onto the antenna feed point for best results (no measuring faults due to the influence from feeder coax length).
- Small (ca. 6.3 x 6.3 x 4.3 cm3) and light (abt. 100g).
- 5V power and communication from/with a laptop through a thin and long (up to 12.5m is tested) USB cable.

- Correct VSWR indications between VSWR=1:1,0 tot VSWR=1:13 or higher.
- Simple resistive measuring circuit. The specialized software calculates and corrects received data for correct VSWR plots.

This small and simple to use gadget can be handy for adjustments of / to :
- Correct coupling to and matching of loop antennas.
- lengths of antennas .
- Traps in antennas.
- RF power transformers.

        Component purchase suggestions :
a. The (6-lead SOT-23 IC) AD8361ARTZ can be ordered her

b. The 5V/16MHz Arduino Pro Micro board and 9851 30MHz Xtal HC-SR08 DDS board can be ordered at tinytronics.nl (or on eBay). Be sure you order these versions.
c. Action sells very cheap thin 2.5m long USB and 5m long USB coupling cables..
d. All other components have wires or pins and are easy solder able.
e. All used software is free.


Functional check
Calibration (corrections

Schematic details Operation


Sweep of my 10m. circumference loop, tuned to 80m, and matched to VSWR=1:1 by an extra transformer. Measured at the transmitter connection of the coax feeder.


Sweep 1-30MHz of the same 10m circumference loop, tuned and matched to 7.1 MHz.

Sweep of a 1m long RG058CU coax cable with one open end.