These baluns and ununs can be used for impedance matching and also as End Fed halfwave antenna matching transformers to 50 or 75 ohm coax cable.
Elecraft KPA500 HF Linear Amplifier RFI Kit - 5 Filters for RF In/Out, AC Power, PA KEY, Computer Control/AUX/RS232
This is a generic linear amplifier RFI kit for DC powered amplifiers. Works on many popular amplifiers including:
Specially designed for the Elecraft KPA500 linear amplifier used with the KX3 and similar transceivers.
Included are the following chokes and installation guidelines:
Included are the following chokes and installation guidelines:
RF Input:F240 ring – 5-9 turns of RG-58 size through center
RF Output:FSB-1 (Big Clamp on) – 3 turns of RG-8 size cable
PA KEY Cable:FSB-1/2 – multiple turns through choke – ½” diameter hole
AC Power Line:F240 ring – 5-6 turns through center
Computer/RS232/AUX Cable:FSB-1/2 – multiple turns through choke – ½” diameter hole
Also make sure you connect a good RF ground to the amplifier ground post.