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TX antenna - 4SQ-8DIR NEW 8 directions 4SQ antenna
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!TUNNING ANT elements '''{.redka#id color: #f23f37; font-size: 200%}⚠{/} NOTE: Input SWR of the hybrid is not SWR of the antenna!!!''' '''{.redka#id color: #f23f37; font-size: 200%}⚠{/} NOTE: If you do not connect any ANT into all 4 ports, SWR on you TRX is very close to 1:1 but ALL power is going to dummy load = ANT SWR is ∞:1!!!''' '''{.redka#id color: #f23f37; font-size: 200%}⚠{/} NOTE: Do not forget thar SWR 2:1 on antenna elements is 1/10 of INPUT power to dummy load (DL)!! 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. * three of tham: !!With SWR LED bar indication ** Do *[SWR LED bar settings|https://qro.cz/remoteqth/wiki/index.php?page=TX+antenna+-+4SQ-8DIR+NEW+8+directions+4SQ+antenna#SWR_LED_bar_settings] at first ** TX with your TRX on RTTY (FSK) and tune TRX frequency 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 PWR meter ** Connect PWR meter between RF hybrid and dummy load ** TX with your TRX on RTTY (FSK) and tune TRX frequency 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 ** 1/10 of the input power in the dummy load (shown on your PWR meter) means SWR 2:1 * [bigger picture|https://remoteqth.com/img/ZAW-WIKI/4sq-8dir/with_pm_940.png] [https://remoteqth.com/img/ZAW-WIKI/4sq-8dir/with_pm_850.png|noborder] !! With 2-port VNA or Spectrum Analyser with TG ** 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 !!! * [bigger picture|https://remoteqth.com/img/ZAW-WIKI/4sq-8dir/with_vna_940.png] [https://remoteqth.com/img/ZAW-WIKI/4sq-8dir/with_vna_850.png|noborder] - Return loss (RL) in dB to SWR: ONLINE calculator [RL to SWR|https://cgi.www.telestrian.co.uk/cgi-bin/www.telestrian.co.uk/vswr.pl] [https://remoteqth.com/img/ZAW-WIKI/4sq-8dir/swr1kw.png]
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