Re: Covid..and making phased loop antenna array..


Simon
 

Hi Paul

Yes and no..

Cat5 has 100r impedance..so one has to alter output transformer on preamp ( if designed for 50r.)
Also at bias tee one needs an isolation transformer 100r to 50r to connect to rx. Thats if you want to do it properly..plus send power up another twisted pair ( 4 twisted pairs in cat5e.)

Chris I know made stuff using cat5 but ( i may be mistaken here!) it “put people off” as takes abit more work..???

However the end results are worth the effort..

High end cctv all use cat5e or similar cable..not coax..( unless running wireless.) the same reason they use it applies to us.ie low loss..balanced feeder..zero to very low common mode interference AND ITS cheaper!

The best tx feeder is open wire balanced ..same principle but MUCH harder to implement ( hence why coax is so popular..) ie feeding though a wall etc..

If you suffer from common mode interference on your rx loop/s, then i would recommend working out how to fit cat5e..( screened.. solid copper..uv resilient ( outside grade.))

One can buy mini transformers 100r cat5e to 50r bnc ..designed for cctv..easy fit..BUT i have no idea of frequency range of said devices..

Also..one has to use a seperate twisted pair in cat5e to run power..you do not share rf twisted pair with the power..ie example..rf orange plus orange/white.
12v green plus green/ white..
12v supply has to be feed via comon mode choke at feed and at preamp..( chokes will do at preamp.) circa 100uh..

Sounds complicated but not once get head around it..

Simon

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