New Bowtie Page 3/21
THE NEW BOWTIES
With the recent channel repack the UHF band has been reduced to channels 14 to 36 (470-608 MHz). Many stations have now moved to lower frequencies and this has brought about changes in the way recieving antennas are constructed.
I present some alternatives that will perform better with the new channel lineup. Links @ page bottom.
The FF4 by holl_ands
This antenna was developed by holl_ands (and others) sometime in 2017 to meet the needs of the UHF channel repack to 470 - 608 MHz.
Now in 2021 with the repack finished, this model and the others presented, completely fill the need for optimized elements to receive the UHF band. Schematics Here
Measurements
FF4 Backbone layout. Material your choice.
Top bay to 1st inner bay - 12.5"
1st inner bay to center of feed point 6.75"
Feed point to 2nd inner bay 6.75"
2nd inner bay to bottom bay 12.5"
All measurements on center.
Bows
Top and bottom bay bows 9.5", Tine spread 7.5"
Four inner bows 12.0 - 12.5", Tine spread 8.5"
Phase line separation 2.50" - 3.75"
More information and building videos are in the works. If you can build from the numbers, go for it.
Check it out...
Whats Going On Here ??
This FF4 and the FF6 are unique UHF antennas as they have a free Form design, meaning they have different sized elements focused on the changing wavelengths within the UHF band. As channel numbers go up above 29 the wavelength shortens. The two optimized element arrays combine the longer and shorter wavelengths while maintaining gain and taming the SWR that increases above ch. 29 on the longer elements. Smooth interference free combining of wavelengths for better performance, simple technology borrowed from the log periodic VHF antennas. Good Stuff.
