When should I switch antenna inputs on the Yaesu FT-897D?

Question

The Yaesu FT-897D has two antenna ports: "HF/50 MHz" and "144/430 MHz". The manual states:

The "HF/50 MHz ANT" jack is used for HF and 50 MHz, while the "144/430 MHz ANT" jack is used for 144 MHz and 430 MHz.

I haven't been able to find anything in the manual about what happens between 54 MHz and 144 MHz. For example, say I have a 100 MHz upconverter. Should I be using the "144/430" or the "HF/50" antenna input to receive WWV at 110 MHz?

At which frequency should I switch from the HF antenna port to the VHF/UHF port?

Answer 1

The manual lists

Frequency Range: Receive: 0.1-56 MHz, 76-108 MHz, 118-164 MHz, 420-470 MHz

and

Intermediate Frequencies: 1st: 68.33 MHz (SSB/CW/AM/FM)

So the HF/50 port should be used for reception below 56 MHz (high side injection), and the VHF/UHF port should be used above 118 MHz (low side injection).

It's not obvious from the manual which port is used for 76-108 MHz, but it's probably the V/U port, and that range is only usable for WFM (broadcast FM radio) reception anyway. Furthermore, there's no receive coverage between 108 and 118 MHz. So an upconverter with a 100MHz LO would be a poor match for this radio.