Ok, so my thing is mobile radio, be that on foot, bicycle, or in the car, usually by the sea, however I spend a lot of time driving to and from work so that forms the bulk of my on air time.
When I park up for a DX session, I like big antennas, 1/4WL antennas to be precise, now this isn't such a problem for 10 or 12m, but a 1/4WL soon grows in size when one starts to go lower in frequency. I had been thinking about making a multiband 1/4WL antenna, manually adjustable, that would attach to my car, there were a couple of requirements that the antenna had to fulfil.
1) sturdy, we get a lot of wind by the sea and I've had a fibreglass antenna snap previously
2) Multiband of course
3) Work on my favourite DX band, 20m
4) Roof height, no obstruction or opposing currents from the car
5) Easy to deploy
Well the best I could come up with is a converted CB 1/2WL antenna, the Silver Rod, as it is known in the UK, seemed to fit the bill, alloy construction, comes with mounting flange and fittings, easy to modify, easy to tune, and sturdy, here's how it's working out, from modification to deployment:
The impedance transformer in the base of the antenna
The coil attached to the SO239 socket
The removed coil, apparently capable of handling 1000W
Coil bypass wire in place of the coil
Coil bypass wire soldered to the SO239 and ready to close up
In the transit position ready for driving
Antenna in use, a trailer hitch and short stub mast below the antenna
I haven't finished yet, I've got to install some ground straps from the base of the antenna to the door frame of the hatchback, run a choked coax through to the transceiver and fine tune and mark the antenna up for the different band positions.
As a quick test I ran a long coax lead through to the rig, the length accounting for the missing ground and relying on CMC to make up the other half of the antenna. I tuned through 20m and found a friend of mine was out locally pedestrian mobile, he was working a VE7 so I joined in, but due to a high noise level I couldn't hear the VE7, however he could hear me better long path than short path, which is no surprise as my house was blocking me to the North. The second station that called in was on the Island of Mauritius, a rare DX entity on any band, both my friend and I were around 58 with him and he 59 with me, I didn't stick around any longer, I had to get my gear packed away as I had other things to do, but I was very happy with my first contacts on the new antenna.
For info the antenna cost around £25, the tow hitch assembly £75, this is just the first of many antenna projects for the car, looking forward to some warmer weather before I build the rest
Edit: just realised I put this in the CB section, I don't mind it being here if you guys don't :blushing:
When I park up for a DX session, I like big antennas, 1/4WL antennas to be precise, now this isn't such a problem for 10 or 12m, but a 1/4WL soon grows in size when one starts to go lower in frequency. I had been thinking about making a multiband 1/4WL antenna, manually adjustable, that would attach to my car, there were a couple of requirements that the antenna had to fulfil.
1) sturdy, we get a lot of wind by the sea and I've had a fibreglass antenna snap previously
2) Multiband of course
3) Work on my favourite DX band, 20m
4) Roof height, no obstruction or opposing currents from the car
5) Easy to deploy
Well the best I could come up with is a converted CB 1/2WL antenna, the Silver Rod, as it is known in the UK, seemed to fit the bill, alloy construction, comes with mounting flange and fittings, easy to modify, easy to tune, and sturdy, here's how it's working out, from modification to deployment:
The impedance transformer in the base of the antenna
The coil attached to the SO239 socket
The removed coil, apparently capable of handling 1000W
Coil bypass wire in place of the coil
Coil bypass wire soldered to the SO239 and ready to close up
In the transit position ready for driving
Antenna in use, a trailer hitch and short stub mast below the antenna
I haven't finished yet, I've got to install some ground straps from the base of the antenna to the door frame of the hatchback, run a choked coax through to the transceiver and fine tune and mark the antenna up for the different band positions.
As a quick test I ran a long coax lead through to the rig, the length accounting for the missing ground and relying on CMC to make up the other half of the antenna. I tuned through 20m and found a friend of mine was out locally pedestrian mobile, he was working a VE7 so I joined in, but due to a high noise level I couldn't hear the VE7, however he could hear me better long path than short path, which is no surprise as my house was blocking me to the North. The second station that called in was on the Island of Mauritius, a rare DX entity on any band, both my friend and I were around 58 with him and he 59 with me, I didn't stick around any longer, I had to get my gear packed away as I had other things to do, but I was very happy with my first contacts on the new antenna.
For info the antenna cost around £25, the tow hitch assembly £75, this is just the first of many antenna projects for the car, looking forward to some warmer weather before I build the rest
Edit: just realised I put this in the CB section, I don't mind it being here if you guys don't :blushing: