Doublet-Isolators for 300 Ohm Twin Lead by DH1ND

Last crawled date: 3 years ago

The shown Isolators are suitable for building a incredible Multiband Shortwave Antenna.
The Isolators are screwed using M3x10mm cylinder head slotted Screws (x10) as well as M3 hexagonal Nuts (x10). If the Isolators must be permanently protected against moisture, an additional adhesive for sealing can be used. An SO-239 socket is also needed. The center pin must be shortened to 1mm. The Twin Lead is connected to the center pin and the socket housing (prepare soldering points with a saw and file for iron).
For centering, a 3mm hole is drilled at each end of the Twin Lead. If, by mistake, the guide pin should break, the tensile strength of the Twin Lead is nevertheless guaranteed by the clamping.
The Antenna Wire (Dipole) to be used should have 2mm to 3mm outer diameter (including isolation). A very cheap Antenna Wire for the setup as Inverted Vee I ordered on eBay (http://www.ebay.de/itm/161866630753). You can get best Wire Quality and other stuff from the Webshop of DX-Wire.
The used Twin Lead (300 Ohm, Velocity-factor 0,82) can also be obtained at http://www.dx-wire.de/lng/en/kabeldraehtelitzen/300-ohm-bandleitung/300-ohm-twin-lead.html?type=N&language=en
Proven lengths for the Doublet and Leads correspond to ZS6BKW or G5RV Antenna model.
For example:
G5RV 6-Band (included 160m): 2x 30,94m (Dipole) and 17,20m Twin Lead
G5RV 5-Band (included 80m): 2x 15,47m (Dipole) and 8,60m Twin Lead
G5RV 4-Band (included 40m): 2x 7,74m (Dipole) and 4,30m Twin Lead
Please remember to cut each leg of the Dipole approx. 4 cm longer for the assembly of the EndIsolators. The Endisolators are simply attached with narrow Cable Ties at the bent ends.
The shown Balun for undefined Impedances is not required for portable operation of the Antenna (potentialfree) but generally recommended. A Ferrit for max.100 Watt is available from: http://www.dx-wire.de/lng/en/ferriteringkerne/ringkerne-zur-funkentstoerung/t36/23/15-3s4.html?type=N&language=en
The Balun consists of 13 turns of Twins (best choise is PTFE http://www.dx-wire.de/lng/en/kabeldraehtelitzen/ptfe-teflon-litzen-und-draehte/ptfe-teflon-wire-twisted-2-x-075mm2.html?type=N&language=en) and is between Antenna and Tranceiver (or extern Tuner) connected.
An Antenna Tuner is required for real all-band-operation. In most cases, the built-in Tuner in the Transceiver is sufficient. More Details you can find under G5RV in the Internet.
vy 73 es 55 de DH1ND