Home |
Search |
Today's Posts |
#6
|
|||
|
|||
Coils getting hot in antennatuner. Is this normal ?
D. Huizinga wrote:
My 40 mtr doublet is fed with a balanced line of 300 Ohms. Nicely tunable to 1:1 . But after twenty minutes or so the coil gets rather hot! It is a quality coil of 3 mm and shiny silvered or chromed on a ceramic body of 1 inch. I once had a similar problem using a 130 foot dipole fed with 450 ohm ladder-line on 40m. The SWR on the ladder-line was about 15:1 and the 4:1 balun was looking into 30 ohms. The balun presented 7.5 ohms to the tuner and the coil got hot. That's when I decided to come up with my no-tuner approach at: http://www.w5dxp.com/notuner.htm Is your 40m dipole 66 feet long fed with 60 feet of 300 ohm twinlead through a 6:1 balun? If so, your tuner is installed in a lossy configuration and heating is to be expected. The simulator at: http://fermi.la.asu.edu/w9cf/tuner/tuner.html says that 16% of the power is lost in the tuner. 16 watts is enough to heat up a coil. Ever touch a 15w appliance bulb when it is on? -- 73, Cecil http://www.w5dxp.com |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
FS: Vintage CB Gear Johnson 100 w/box and manual plus Archer AntennaTuner & CB Tester | Swap | |||
Back to normal? | Policy | |||
Normal in Amateur Radio | General | |||
antennatuner TS450SAT | Equipment | |||
antennatuner TS450SAT | Equipment |