In a message dated 29/06/05 23:50:28 GMT Daylight Time, [EMAIL PROTECTED] writes:
Check the base impedance at hf. Some antennas have a vhf matching circuit in the base that will look like nearly a short at hf. If it doesn't show an open circuit at hf, Reply:--------------------------------------------- What Bob, N6WG mentions are the VHF antennas that are 1/2 wavelength or multiples of this and where the antenna feed end is at a high impedance. To match this a coil is inserted into the antenna base with the incoming 50 ohm feeder tapped in at an early point on the coil. Normally this type can be located even with a sealed marine type antenna by checking the resistance across the unplugged antenna lead should read S/C looking towards the antenna. This type of VHF antenna should not be capable if working on HF. However if there is no measurable S/C there is a good chance the antenna is one that is a multiple of a 1/4 wavelength and as such could be used as a short whip antenna for HF, though with rather limited efficiency. Bob, G3VVT _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
