GW4ALG's QRP Radio Pages

[ GW4ALG went QRT in February 2007 ]

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Doublet Antenna

This antenna was re-installed at GW4ALG in May 2002, after having used a delta loop for many years.  The present antenna is an inverted-V doublet (that is, a centre-fed antenna) built to the 'full size' G5RV dimensions.  A balanced feeder  runs from the top of a support pole mounted on the gable end wall; through the house wall; through the loft [attic]; and then through the ceiling into the upstairs shack.

The balanced feeder consists of homemade open wire line (at the feed point), and sections of mains cable (on the indoor feeder section). 

 

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At the shack end, the doublet has been tuned successfully on 10 - 80 m using the classic 'Z Match' balanced antenna tuning unit (ATU) for all bands. 

More recently, I have been experimenting with baluns and the use of ATUs installed between the balun and the transmitter (and transmitters having built-in automatic ATUs).  This has resulted in very encouraging results on all bands between 6 m and 80 m.