I dont know what kind of an isolatuion transformer you guys are using, i come from a vintage view point where no ferrite or coax is ever used except to go from the transmitter final coil to the antenna coil.
coupling is just some #14 insulated wire around the whatever coil i am going from to a wiinding on whatever coil i am going to, loop coupling everywhere, even in my receiver designs for antenna tuning make the coil the length needed to get an swr =1.0x or so, no matter what size of variable cap you need to resonate mike w7dra On Thu, 8 Dec 2011 18:41:41 -0800 "Rick Karlquist" <[email protected]> writes: > W0UCE wrote: > > > * The ONLY means of achieving the required degree of > Isolation is to > > use the Isolation Transformer as specified by K2AV > > * Tests using 1:1 Baluns and Line Isolators have ALL FAILED > - you > > waste RF Power, Time and Money unless the specified xfmr is > installed > > * DO NOT attempt to use Insulated Window Line for the FCP - > We already > > tried it and it does not work - too lossy > > * Use #12 Bare wire for the FCP elements - Moisture gathers > on > > insulated wire and detunes the FCP > > I haven't built this system, but the suggestions above make sense. > I have been trying to encourage using transformers instead of > baluns > on 160 meters for years, but it's a tough sell to overcome the > balun > habit. The tendency for loss in the open wire line also makes > sense. It is well known that window line is lossy when wet. > What is new here is that the Q is so high that you can't even > use insulated wire for open wire line. It would be interesting > to see if teflon insulated wire worked OK. The electric field > is maximum right at the conductor surface, so the insulation has > a considerable effect on characteristic impedance, thus I could > imagine it would affect loss too. I am feeding my vertical > using 850 feet of open wire line with XHHW insulation (whatever > that is made out of). It would be interesting to measure the > loss on a rainy day and see how much it increased. It's only > a few tenths of a dB when dry (the wires are 4 AWG aluminum). > > Rick N6RK > > _______________________________________________ > UR RST IS ... ... ..9 QSB QSB - hw? BK > ____________________________________________________________ 2.6% Mortgage Refinance No Hidden Fees - 3.14% APR. Calculate New Payment. No SSN req http://thirdpartyoffers.juno.com/TGL3141/4ee18c26bacc18f4751st02vuc _______________________________________________ UR RST IS ... ... ..9 QSB QSB - hw? BK
