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pa0nhc SWRsweeper V2
20170531


PCB #51


PCB #71

PCB #51 is sold out.
New version PCB #75 is ordered in limited quantity.

          The new #75 PCB is designed for :
1. cheaper BNC chassis connector     CONRAD  740632
2. easier to solder AD8361ART6lead SOT-23, orderable  
here   (Verical)
3. easier fit of the Arduino and DDS boards, due to wider pin holes in the main board

            Introduction  "SWR sweeper V2"  20170527 (all further details for PCB#51) :
- 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 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 tiny AD8361ARMZ (8-lead SOIC, brand J3A) are quickly delivered from
arrow.com (or much cheaper on eBay , but with much longer delivery time).

b. The Arduino Pro Micro board (5V/16MHz version) and HC-SR08 (9851 30MHz Xtal version) DDS board can be ordered at tinytronics.nl (or on eBay). Order these versions !!
c. Very cheap thin 2.5m long micro USB cable and 5m long USB coupling cables obtain able from Action.
d. All other components are easy solder able with wire/pin connections.
e. All used software is free.

Downloads

Soldering
Modifications
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 with extra transformer to 3.6MHz. 
Length of the coax feeder abt. 16m.


Sweep 1-30MHz of the same 10m circumference loop, tuned and matched to 7.1 MHz.
Length of the coax feeder abt. 16m.


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


Rf power matching transformer for 80m.
#61 65mm ferrite ring core with 38t coil, antenna tap at 30t.
Measured at the coax feeder connection with transmitter connection matched to 51 Ohm.