Home |
Search |
Today's Posts |
|
#1
|
|||
|
|||
Balun for PI network antenna tuner
Another ham gave me a homebrew PI network tuner he used to tuning
single wire feed antennas. I'm planning to build a multiband antenna and feed it with twinlead or ladder line since it's less lossy than coax. I'd like to make or buy a balun for this tuner. I don't plan to run more than 100 watts, and will probably start experimenting with QRP operating as well. Any guidance is appreciated. Red |
#2
|
|||
|
|||
Red,
Well, a balun at the antenna side of the tuner is what most people would do. Unless you use a link coupled or double balanced tuner, there really isn't much else of an alternative. 1:1, 2:1, 4:1, 9:1 or what? Well, you're going to see quite large impedance changes based upon what antenna you use and what bands you operate. You'll likely get a good match on some bands and not so good on other bands. I'd recommend a 4:1 balun as a compromise. And don't forget those HF swap nets. Best of luck and 73s, Evan, K9SQG |
#3
|
|||
|
|||
You will need a 1:1 choke balun between the tuner and the balanced feedline
to the antenna. Obtain an HF-quality ferrite ring, about 1.75 inches in diameter. Permittivity around 200-400. Wind on 8 or 10 turns of 18 or 20 gauge, stranded, flexible, figure-of-eight, twin speaker cable. This should cover the range 1.8 to 30 MHz. ---- Reg, G4FGQ |
#4
|
|||
|
|||
Reg, I'm afraid your "figure-of-eight" lost me. What's that? 'Doc |
#5
|
|||
|
|||
Here in the states we would call it lamp or Zip cord.
-- John Passaneau, W3JXP Penn State University "'Doc" wrote in message ... Reg, I'm afraid your "figure-of-eight" lost me. What's that? 'Doc |
#6
|
|||
|
|||
Is lamp or zip cord twisted with a fairly short lay?
The stuff I have in mind for baluns lays flat. Colourless. It may be sold as speaker cable. It has lower copper loss then coax, easier waterproofed and constructed. ---- Reg =========================== Here in the states we would call it lamp or Zip cord. |
#7
|
|||
|
|||
Figure-of-eight . . . .
Two circles stuck together. Outline of plastic insulation surrounding a pair of close-spaced wires. Zip-cord ? --- Reg -- .................................................. .......... Regards from Reg, G4FGQ For Free Radio Design Software go to http://www.btinternet.com/~g4fgq.regp .................................................. .......... "'Doc" wrote in message ... Reg, I'm afraid your "figure-of-eight" lost me. What's that? 'Doc |
#8
|
|||
|
|||
Reg, Okay, now I understand what you're talking about. For a while there, I thought you may have been talkng to Mr. Moebus...? 'Doc |
#9
|
|||
|
|||
On Thu, 22 Jan 2004 15:30:52 +0000 (UTC), "Reg Edwards"
wrote: Figure-of-eight . . . . Two circles stuck together. Outline of plastic insulation surrounding a pair of close-spaced wires. Zip-cord ? --- Reg Apparently because when you separate the two at the thin part at one end, you can just zip it apart easily as far as needed. |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Inverted ground plane antenna: compared with normal GP and low dipole. | Antenna | |||
Mobile Ant L match ? | Antenna | |||
Poor quality low + High TV channels? How much dB in Preamp? | Antenna | |||
QST Article: An Easy to Build, Dual-Band Collinear Antenna | Antenna |