TX antenna - 2EL antenna array 4 direction

This revision is from 2018/06/11 22:02. You can Restore it.

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This is TX-RX antenna mainly for lower bands. It is based on classic 4SQ with 90deg phase hybrid.

Quick Start Guide

Connector description

  • There is standart RJ45 (ETHERNET) connector with shielding

  • There is standart D-SUB 15 female connector with shielding

  • Table

  • Connectors on Hybrid PCB:
    • detector = dummy load power (pin 6 on controller)
    • 1 = DIR1 , 2 = DIR2

SWR LED bar settings

  • ⚠ NOTE: Input SWR of the hybrid is not SWR of the antenna in W-E directions!!!
  • ⚠ NOTE: For N-S direction, there is no power to Dummy load. Input SWR follows SWR of antennas!

SWR Range trimmer - Range of PWR in dummy load

Setting step by step

    • Connect TRX (PA) to the 2EL hybrid - to Input port
    • Connect Dummy load to the Dummy Load port ( you can insert PWR meter too )
    • DO NOT connect any antenna element - leave it open
    • Switch direction on controller to WEST or EAST
    • Than when you TX (RTTY mode) all power goes to the dummy load port
    • Open controller box
    • There is SET SWR trimmer (blue one)
    • With this trimmer you can set full range of LED bar for prefered MAX power in dummy load

⚠ NOTE: Do not forget thar SWR 2:1 on antenna elements is 1/10 of INPUT power to dummy load!! So for 1kW and SWR 2:1 is 100W in DL. There is no problem to have only a few Watts in DL when the antenna elements are right tuned!

    • So set TRX power to your max PWR you want have in dummy load and set SET SWR trimmer to full LED bar range
    • When LAST red LED is on, than PTT loop is disconnected * see jumpers setting

⚠ NOTE: When you set full scale for some PWR, for example 200W. Than you can go down with PWR from your TRX and you can see what PWR = LED COUNT. What is half of scale, first LED etc.

Jumpers setting

  • When power in dummy load exceeds value you you set before, than protection circuit breaks PTT loop and Buzzer sound is ON.
  • Jumpers:
    • JP1 = ALARM - switch ON/OFF buzzer and PTT LOOP break
    • JP2 = LED BAR mode (dot/line)

    • JP3 = supply voltage for RF box relays - controller voltage or External
    • JP5 = external CW/SSB segment relay - external antenna tunning: example

CHANGE LED INDICATION FOR THREE DIRECTIONS.

    • JP4 = W N-S E
    • JP6 = NW SW-NE SE
    • JP7 = SW NW-SE NE
    • JP8 = N W-E S

FEED lines length

- All ports on RF hybrid box are 50 Ohm. Antenna elements are connected to the box with 50 Ohm coax cables.

- The best way is to use Lambda/4 feed line lengths to take advantage of the current forcing properties of this length of line.

LENGTH IN METERs !!!

TUNNING ANT elements

⚠ NOTE: Input SWR of the hybrid is not SWR of the antenna for directions W ane E!!!

⚠ NOTE: Do not forget thar SWR 2:1 on antenna elements is 1/10 of INPUT power to dummy load (DL) for W and E directions!! So for 1kW and SWR 2:1 it is 100W in DL. There is no problem to have only a few Watts in DL when the antenna elements are right tuned!

There is a few ways how to do the right antenna elements tunning.

  • With SWR LED bar indication *** for directions W or E ***
    • Do *SWR LED bar settings at first
    • TX with your TRX on RTTY (FSK) and tune TRX over the band
    • You can see, where is the minimum power in dummy load = best SWR
    • You can increase PWR (use PA) and find the minimum
    • So if you set full scale of LED bar graf to 200W, and you TX with 2 KW into the antenna, you can see SWR 2:1 range
  • With SWR meter on your TRX / SWR meter / VNA *** for direction N-S ***
    • TX with your TRX on RTTY (FSK) and tune TRX over the band
    • You can see, where is the minimum SWR on your TRX / SWR meter / VNA
    • YTune around the band and find the minimum
  • With 2-port VNA or Spectrum Analyser with TG *** For directions W or E ***
    • Very nice way how to SEE antenna parameters is with VNA or SA
    • Connect TX and RX port with short cable and do calibration
    • Than connect TX port of VNA (TG on SA) to the IN port of hybrid
    • RX port of VNA (IN of SA) connect to Dummy LOAD port on hybrid
    • Connect all antenna elements
    • Connect controller
    • Now you cas see S21 parameters of antenna
    • This will change with direction switching
    • You can see the minimum of S21 what is the best SWR of antenna
    • Frequency where there is that minimum, there is best SWR of antenna
    • For example S21 = -20dB means 1/100 of Input power to dummy load
    • On right tunned elements you can have more than -30dB ! what is 1W from 1kW !!!

- Return loss (RL) in dB to SWR:

ONLINE calculator RL to SWR

ToDo

  • Cable wiring circuits