[Elecraft] Re: BL1 Balun

[Todd Fonstad]

Joe, AA4NN, posted:

"With K2/100 100w out after two QSOs on 40m overall about 40 minutes the BL1 balun is quite hot to the touch. This is the first time I have used the BL1 
with a CF Zepp. Amazing SWR 1:1 80m-10m, works great. I'm thinking I might  need to glue a heat sink on that toroid. Anybody done this or am I too much 
QRO and heat is normal. hi"

I have used the BL-1 at both QRP and 100 watt levels on a couple of  ladder-line fed doublets designed for multi-band operation. If you are using the ATU, the 1:1 SWR you are observing is what the K2 is "seeing" courtesy of the tuner. The actual SWR presented to the balun may be very high. The heat you observed from your balun is wasted RF. My BL-1 has quickly heated, then saturated, using 100 watts into both 265' and 176' doublets on 160, 80, and 40 meters. It is fascinating, although dismaying, to see the SWR LEDs on the ATU rise from green (low SWR) to red (high SWR) in a matter of seconds as saturation occurs. I'll continue to use the BL-1 at QRP levels but will "wind my own" more robust balun for QRO operation. 

73
Todd
N9NE