- This topic has 4 replies, 3 voices, and was last updated 18 years ago by
Mike Bennett.
Mike Bennett.-
Posts
-
mule
I sat down and tried to come up with a reasonable Yagi antenna frequency variation modifier. Based on two length data sets with the known frequencies, I came up with a loose estimate on what the lengths of the rods would need to be to get in the 420-450 mhz range assuming a 1/32″ change in lengths.
Here is what I decided on, I think it should get it close to a .05 mhz +/- range. That is what I need someone to double check for me…. There has to be someone on here with a better methodology than a calculator and a spreadsheet……
Per .031″ change, a 3.98 mhz change occurs using a 24×17.5×11.5×5.5×2.5 spacing between the rods. Starting with the reflector and working out.
Or, does the ARRL maybe have a chart that works better??????
Warren B. Musselman
Most definitely. Somewhere around here I have an article printout from an old QSL magazine on the design and construction of small 3 to 18 element Yagi’s for 70cm bands. If I find it, I’ll post it here on the website for others.
Warren
Mike Bennett
Use this to make your yagi:
Quick Yagi Copyright By Chuck Smith and RAI Enterprises, Inc. Very nice freeware program to design a yagi antenna to your frequency. You set the parameters or let the software auto design an antenna.
mule
Use this to make your yagi:
Quick Yagi Copyright By Chuck Smith and RAI Enterprises, Inc. Very nice freeware program to design a yagi antenna to your frequency. You set the parameters or let the software auto design an antenna.
WOW!!!! Thanks. That’s just what I needed. And, now it’s posted for others to see as well! 😀
Hey, we need some of the “happy clapping” Emoticons on here…Greg
Mike Bennett
Well Warren maybe we should download the file to this web site and not use Scott’s site for a hotlink to it and save some of his bandwidth.
mule
Warren B. Musselman
Mike Bennett
- You must be logged in to reply to this topic.