McBad
Active Member
- Posts
- 107
- Location
- Cardiff, Wales, UK
Hi guys, I'm looking for some advice on fixing high SWR on my CB set up. I know there are some CB gurus on here.
CB is a Midland 77-095; it's been sat in the shed for 20 years but I don't see why it shouldn't work. As I had the head-lining out of the disco I ran some new coax to a new dome-mount in the centre of the roof, to see if I could get it working. Aerial is a new 3' springer.
I've put it all together and I can receive but I get massively high (~3) SWR readings if I press the transmit button.
I've used my multi-meter and I have good continuity all the way from the metal of the roof through the braiding layer in the cable to the metal of the plugs on the back of the radio and SWR meter. I also have good continuity down the centre of the cable, from the plug to the aerial mount to the plug at the radio. There is no short circuit between the core and braid layer of the cable.
I've tried SWR readings on Ch 1, 20 and 40 and they all come back with a reflected signal strength of very close to 3. Small difference in readings across the range suggests the aerial needs shortening, but the fact that they are so high to start with suggests there is a more major problem.
The aerial itself is a metal whip with the coil at the bottom and there is good continuity between the tip and the scewthread at the bottom.
Any ideas please folks?
M
CB is a Midland 77-095; it's been sat in the shed for 20 years but I don't see why it shouldn't work. As I had the head-lining out of the disco I ran some new coax to a new dome-mount in the centre of the roof, to see if I could get it working. Aerial is a new 3' springer.
I've put it all together and I can receive but I get massively high (~3) SWR readings if I press the transmit button.
I've used my multi-meter and I have good continuity all the way from the metal of the roof through the braiding layer in the cable to the metal of the plugs on the back of the radio and SWR meter. I also have good continuity down the centre of the cable, from the plug to the aerial mount to the plug at the radio. There is no short circuit between the core and braid layer of the cable.
I've tried SWR readings on Ch 1, 20 and 40 and they all come back with a reflected signal strength of very close to 3. Small difference in readings across the range suggests the aerial needs shortening, but the fact that they are so high to start with suggests there is a more major problem.
The aerial itself is a metal whip with the coil at the bottom and there is good continuity between the tip and the scewthread at the bottom.
Any ideas please folks?
M
