Hi i have mfj 989c this reads 57 ohms my home made one using eb** surplus telecoms resistor bolted to heat sink 4 inches square ex audio amp gives 50 ohms and 1 to 1 up to at least 430mhz its rated at 150w and 5ghz cheep i think £3.50 for 5 if memory serves me right just looked they have gon up ti 2.56 each
https://www.ebay.co.uk/itm/RF-termin...YAAOSw0~pcEz~V