Contest Club
QRV since 1993.

Dear OM Peter:

Something you need to know about your website:

The Battle Creek Special is designed for use from 7.0 to 7.3 MHz and the
trap should be resonated close to 7.0, not 7.1 MHz.

On 80 meters the design frequency is 3525 KHz, and the bandwidth is 3500
to 3570 KHz. The trap needs to resonate at or below 3525. The trap
data you give will resonate at 3750 KHZ which will reduce the
performance on 80 CW and may give other problems. The capacitance to
resonante 9 uHy at 3.5 MHz is about 225 pfd.
The Battle Creek Special uses two pieces of RG-213 about 4 feet long, in
parallel, to get this capacity and they hang below the trap inside the
top section.
Please correct your diagrams to reflect this.

Also do not forget the 2:1 UnUn (9:4 UnUn also works) to bring the
impedance on 160 up to about 50 ohms.


With L=9 uHy, C is best at 229 or 230 pfd for resonance nearest 3500 KHz

With C = 200 pfd, L is best at 10.33 uHy for resonance at 3500 KHz

73 George K8GG Battle Creek, Michigan

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