VK2CSW > 10-10-2018, 05:54 PM
VK4ADC > 10-10-2018, 07:34 PM
VK2CSW > 11-10-2018, 04:15 PM
(10-10-2018, 07:34 PM)VK4ADC Wrote: Consider each half element a loaded 1/4 wave whip and use something like this to determine your inductor when scaling :
https://m0ukd.com/calculators/loaded-qua...alculator/
It won't be exact but will provide a guide.
Remember to scale the spacing between REFlector / DIRector and Driven Element too. A DE plus DIR usually gives slightly better gain than a DE plus REF when dealing with 2 element arrays.
Typically tune the DE to desired frequency, a DIR to about 5-10% higher, a REF to 5-10% lower.
Final tip: don't actually cut the excess wire length (stage 8 step 2) when going through the tuning process - simply fold it back along the element length initially. Once the proper tuning point is found, only then do you trim the folded-back wire.
VK4WDM > 12-10-2018, 10:27 AM
VK2CSW > 12-10-2018, 02:15 PM
VK4WDM > 13-10-2018, 08:40 PM
(12-10-2018, 02:15 PM)VK2CSW Wrote: Decisions, decisions, decisions...
The yagi could be smaller, but the moxon could be collapsible.
Why do I always end up in analysis paralysis when thinking about antennas?
VK5TM > 13-10-2018, 09:14 PM
Quote:When I started AR in the 1960's aluminum was very hard to come by (at least in ZL) and many HF and VHF beams were made of timber, usually Oregon pine (very hard to get now) or bamboo, with wire elements.
VK4WDM > 14-10-2018, 02:11 PM
(13-10-2018, 09:14 PM)VK5TM Wrote:Quote:When I started AR in the 1960's aluminum was very hard to come by (at least in ZL) and many HF and VHF beams were made of timber, usually Oregon pine (very hard to get now) or bamboo, with wire elements.
Or copper pipe on a timber mast.
Don't remember where it came from but my first 3 el 2m Yagi in ZL (also in the 60's) was copper pipe with a coax feed.