10-10-2018, 07:34 PM
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.
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.
Doug VK4ADC @ QG62LG51
http://www.vk4adc.com
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If you have a comment or question, post it as it may trigger or answer the query in someone else's mind.
http://www.vk4adc.com
This Forum is only going to be as interesting as the posts it contains.
If you have a comment or question, post it as it may trigger or answer the query in someone else's mind.