ATX walkabout

**** THIS ANTENNA DOES NOT SEEM WORK BY SIMPLY ATTACHING A QUARTER WAVE PIECE OF WIRE AT THE LOWEST FREQUENCY AS A COUNTERPOISE TO THE RIG **** I found that the counterpoise length plays a very important part in tuning this antenna . I have heard of people putting these on magmounts and simply plugging the wander lead in and adjusting the whip to tune. I tried this using a magmount on the car with the only bands being tuned 2,6 and 10m.,after this the earth provided by the car was getting less effective for the lower bands and the swr started to rise quickly.I would expect different results depending on the type of car and whether any bonding had been done so there is going to be many people getting many results when using this on a car. When the antenna is used connected to the back of the rig or on a tripod or stand it seems the counterpoise length is just as important as the whip length. I tried two ways to tune this antenna but have listed probably the two most effective ways below. The way i settled on seems a good comprimise against ease of tuning and keeping component numbers( counterpoise lengths ) down as this antenna seems to need a seperate counterpoise for each band and not just one long one.I also found that simply having a bunch of counterpoise wires for each band connected at the same time didn't work as they interacted with each other .This would mean having 9 or 10 seperate counterpoise wires to take out /p. Below you can see my modified camera tripod which is used for all manner of portable and mobile whips.This was just under 10 pounds and the feet extend to just short of 4 foot.

This antenna is supposed to be designed for the ssb portions of the band. As i use mainly cw i wanted the best of both worlds if i could. I didn't have any instructions as this antenna wasn't new so i had a quick look through the net and decided to simply tune from scratch. Tuning for the cw portions of the band meant to work the ssb portions was a simple case of lowering the whip slightly as i went up the band.My first attempt at tuning was aborted half way through as it was apparent i was going to end up with a bunch of counterpoise wires to carry around. I also found each band change required me to take the old counterpoise off and use one specifically for the band i was on. Having the counterpoises all attached at the rig at once didn't seem to work as they interacted with each other even when fanned out. 6,10 M seemed ok but after that problems started so this way was aborted.

tuning

This last section has now been edited as to not confuse the issue of tuning this antenna. The bottom line is it CAN be a pig to tune but i have come to the conclusion there's probably 2 ways to best tune this antenna. First is to simply use a tuneable counterpoise and secondly to use a metal tape measure or a counterpoise wire wound on an old fishing line spool. With the tape measure or fishing spool it's possible to let out the correct amount of counterpoise leaving the remainder on the spool or in the tape measure housing. This is particularly useful as different ground properties at different locations may require a slightly longer or shorter counterpoise but after initial tuning you can mark the tape measure or counterpoise wire which will then always have you in the ballpark area with any minor adjustments done in the field. In both these cases i found using the appropriate tap point and then adjusting the counterpoise for lowest vswr FIRST then adjusting the whip the best way to go.The actual counterpoise length isn't critical to the inch and therefore getting to the point of lowest vswr by adjusting the counterpoise isn't a great task. I also found on most bands i could get the vswr almost flat WITHOUT adjusting the whip enabling me to keep it fully extended for most bands..

i found a length of around 12-15 foot using the tape measure or the counterpoise wire wound on a spool was the longest i needed if i was working only 40m and up. This was almost spot on for 20m also. , i don't use 80 but found 30 foot was fine for ssb portion and around 33 foot for the cw section was adequate.( you may have to experiment with counterpoise length but the procedure should be the same). I simply adjusted the tape/wire for lowest vswr and then tweeked the whip for a flat vswr. I did however find after quite a few different ways to tune that 40m required the whip to be lowered by 1 section in most cases if a 30 foot counterpoise was used, using a 12-15 foot counterpoise allowed the whip to stay fully extanded. Again all other bands were tuned with the whip fully extended to start off with and the counterpoise adjusted to lowest vswr before tuning the whip, in many cases this was all that was needed. So my conclusion is this antenna does tune but is highly reliant on a "tuned" counterpoise not simply a single wire 1/4 wave long at lowest freq of use. This is not the dearest of antennas by far but it performs very well indeed for it's size and performs far better than the miracle whip antenna in my opinion after using both..