Msg # 5725 Type:B Stat:$ To: ALL @IPUF From: KB7CFD Date: 11-Nov/0009 Subject: Butterflys are (almost) free Bulletin ID: 5725_KB7CFD From: KB7CFD@KB7CFD IDAHO PACKET USERS FORUM Looking for a simple inexpencive vhf or uhf antenna? Not into complicated home-brew? Do you like performance? If so then you ought to try a butterfly. This thing is so simple even an eight thumb appliance op can build it. If you can read a tape measure, you have all the talent nessessary to tune it. /\ /\ / \ / \ example: / \ / \ 1005 / 147 = 6.8367 ft / \ / \ or 82.04 inches / \ / \ / each \ / formula \ / loop is \_/ \ < computed _ 1005/fq in Mz> \ with the / \ = / \ / \ len in ft/ \ / \ / \ / \ / \ / \ / \ / \ / \/ \/ #12 solid copper wire works well for 440 and 220.(stripped out romex works well and is cheap!) 3/32 CopperWeld or bronze rod is strong enough for 2M self- support. Since a single full wave quad element is about 100 ohms, the paralel feed dual elements of the butterfly is a very near match to 50 ohm coax. The beauty here is no matching or tuning is nessessary. I have even successfuly co-phased a pair of these antennas with a simple 5/4 wave harness. Performance observed is superior to J-poles (tests on same mast and coax) and near to the performance of an Iso-pole (bi-directionally anyway). It even works well hanging on the wall of the shack (maybe the xyl will macroma it and let you hange one on the living room wall for checkin with the ht on net night. Coax can be soldered directly to the conjunction of the loops, reducing costs and losses with uhf connecters. If you do solder direct, seal the coax end with hot glue or silicon grease.