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Skipper 300 sky high swrs
- Thread starter Staybolt
- Start date
The Skipper feeds the radio's drive directly from the input side of the relay to pin 2 of the driver-tube socket.
Needless to say, this is not a 50-ohm load. More like 200 or 250 ohms. When the Skipper was designed, most base radios used a tube-type final. Driving into a high SWR wasn't so big a deal for a tube-type final, so they skimped on this detail.
A coil wound from solid insulated wire, about 7 turns on a half-inch diameter can be substituted for the direct connection on pin 2 of the driver-tube socket. Squeezing or stretching the turns of the coil for lowest input-side SWR may get it below 2 to 1 with the coil alone. Getting it lower will call for a capacitor to ground on the relay side of the coil. A compression-type trimmer capacitor around 150 pf usually does this job okay.
If you have to stretch the coil way out to get a good match, removing 1 turn and squeezing the remaining turns back together may get you a better adjustment. And if squeezing 7 turns tightly together doesn't get you there, it may require 8 turns.
It's a cut-and-try proposition.
Just remember to re-peak the driver Tune knob on the back after changing this input coil. It will affect the input-side SWR reading.
Can't find any pics of this on file.
73
Needless to say, this is not a 50-ohm load. More like 200 or 250 ohms. When the Skipper was designed, most base radios used a tube-type final. Driving into a high SWR wasn't so big a deal for a tube-type final, so they skimped on this detail.
A coil wound from solid insulated wire, about 7 turns on a half-inch diameter can be substituted for the direct connection on pin 2 of the driver-tube socket. Squeezing or stretching the turns of the coil for lowest input-side SWR may get it below 2 to 1 with the coil alone. Getting it lower will call for a capacitor to ground on the relay side of the coil. A compression-type trimmer capacitor around 150 pf usually does this job okay.
If you have to stretch the coil way out to get a good match, removing 1 turn and squeezing the remaining turns back together may get you a better adjustment. And if squeezing 7 turns tightly together doesn't get you there, it may require 8 turns.
It's a cut-and-try proposition.
Just remember to re-peak the driver Tune knob on the back after changing this input coil. It will affect the input-side SWR reading.
Can't find any pics of this on file.
73
