[Boatanchors] question for SP-600

[Flowertime01 at wmconnect.com]

Bob,

The easy way to go from a balanced antenna to a un balanced receiver is a 75 
ohm to 300 ohm balun from a TV set. These are good to 6 meters or better. The 
transform is 4 to 1. what you want is the core and turns count from the 
inside. You can repackage it with what ever connectors you need. Most receivers have 
more than a 50 ohm input impedance and the 4:1 transform get you more signal 
from the antenna to the receiver. The ferrite core also lets you go from 
balanced to un balanced or un to un or bal to bal. wire it the way you need it.

Twin Ax as feed line can help you keep a lot of local trash from getting to 
the antenna inputs. A good station ground must proceed the twin ax feed line or 
you likely do not gain much. A poor ground on the twin ax shield is still a 
pour shield.

The right angle twin ax connector you seen on E bay is likely the adapter 
connector for the R390 or R390/A receivers. The R390's have a real twin ax 
balanced input connector on them. The right angle connector is grounded on one 
conductor pin and the other conductor pin is the single ended coax input. The 
military used these to feed the receivers from single conductor coax. The very 
front end tuned input circuit becomes upset when you use this input. But the 
receivers still hear very well and the military though it was the way to go. Price 
of twin ax against coax and deaf receivers was just a bean counting exercise. 
A signal not received was just a signal that did not exist.

Hope this ramble helps you.

Roger AI4NI