Workman 40M Antenna Stick: 3-Band Conversion

Transcription

1 Workman 0M Antenna Stick: -Band Conversion : Used with Icom 70 and Elecraft KX1 HFpacks By: WAWSJ/pm I just love to operate pedestrian mobile from anywhere I can hike, drive, bike, ski or crawl. So I put together a very nice Icom 70 Plus HFpack. I did have one self-imposed limiting prerequisite - the counterpoise drag wire could not be any longer than fifteen feet. I have found that a longer drag wire just gets caught on to many objects around me as I walk through brush, cars etc. I also did not want change my drag wire for each band and carry the wires around as I walk the countryside etc. One counterpoise wire for 0m, 0m and 0m is a must for me. I decided to use Workman Antenna Sticks because they are cheap at around $1 each and lightweight. But, I needed to change antenna sticks every time I wanted to operate on a different band. Having this restriction, severely limited how far I could walk away from my truck as this is where I have the other antenna sticks. I then took a Workman 0M Antenna Stick and proceeded to add turns on the top loading coil for 0m CW. After tuning the stick for cw, I found that it needed approximately fifty additional turns of wire to resonate at around 7.100mhz. I suspect that the added turns were needed due to the short counterpoise wire. By adding the extra turns, I now can operate the 0m band from 7.00 mhz to around 7.10 mhz. Since I operate mainly on CW, this portion of the band is fine for me.

2 Next I proceeded to install taps on for the 0m and 0m bands. Hoping to have one antenna stick for 0m, 0m and 0m and only have to move a jumper to change bands on the antenna. After finding the tap points for 0m and then 0m, I installed small loops so I can attach a jumper wire to change bands. To form the jumper loop I used large paper clip wire to form the loop and then soldered it to the coil wire. Here s where the taps ended up on the stick. Starting at the top of the coil section, I placed my top jumper. down. This is after I added 0 turns on top. My 0m jumper is 17.7 down from the top jumper. The 0m loop ended.0 down from the 0m loop or up from the bottom of the antenna loading coil. The overall length of the Workman 0M HF Stick Antenna is I measured the height above ground or HAG to be about five feet. This is where the stick attaches to my ALICE Frame which is on my back. This means the top of the antenna is almost thirteen feet above ground level. I tried to stay around ten feet, but this is the lowest I could get without additional loading and further compromising antenna performance. My counterpoise drag wire measures 1 9 and is just about the proper length to use to hike around here in Pennsylvania. Again, If you try to use a foot drag wire, be aware that you ll need wide open spaces with few or no obstructions in your walking-path. Just walking by a parked-car will present a problem with a thirty-foot drag wire as the wire could easily get caught under a tire hi! This brings up a good point. Make sure your drag wire can pull away from the ground connection! If your drag wire gets caught, you want it to pull off the pack etc. I use an alligator clip to attach my drag wire to the ALICE pack. I ve had it pull off only a few times, but it saved the wire from breaking off! So, after finding the resonate point of 7.08 mhz on 0m, mhz on 0m and 1.1 mhz on 0m, I installed my loops on the loading coil. I could have found closer resonate points to where I want to operate, but these are close enough for me. So, how much bandwidth do I have to operate on these three bands? Well, that seems to vary according to what type of material you are walking on hi! For testing purposes I used only two types of materials. I usually walk on blacktop or ground so these are the two ground materials used for my testing. On 0m, 0m and 0m bands it appears that actual ground, that is soil with grass on top seemed to work best. Look below for the charts of each band tested listing frequency vs SWR on blacktop and dirt covered with grass.

3 I did try this antenna with the same counterpoise wire on my Elecraft KX1 Backpack with excellent results. On 0m I :1 SWR. On 0m I :1. Finally on 0m, where I thought I might have a problem, I :1! This is using the internal antenna tuner of my Elecraft KX1. For this pack I just put together a ¾ PVC pipe frame. The center PVC piece has an old green military steel coppercoated rod inserted in it. On top I hammered on a quick disconnect fitting into the steel cooper-coated old military rod. I then soldered a wire to the rod at the bottom and attached it to a panel mount BNC connector. The whole PVC frame can be taken apart for air travel etc. This allows me to take my Elecraft KX1 HFpack anywhere! I did not glue any of the PVC pipe pieces together at all as they seem to work just fine pushed together and then inserted in the backpack. I also may now take additional items with me while I walk or hike around as there s plenty of extra room in the pack. Here s a look at the top of the pack. The quick disconnect fitting is threaded, but I just used a soft hammer to pound this fitting down into the rod. I now can just push and twist to insert or remove my antenna. This whole HFpack is very light and I even made a belt mount for my KX1 Radio so it is located right in front of me. This is hands-free operation concerning the radio. I just hold my Palm Paddle in my hands - it s great!

4 To use my KX1 pedestrian mobile without holding it all the time, I engineered a cheap, but effective assembly I call my, KX1 Home Depot Belt Mount. This device just clamps on my backpack waist belt and it places the KX1 Radio at approximately three inches above my waist. This is a very convenient spot as the radio is right there in front of you. Here s what it looks like from the side. Please note this assembly is nothing more than two yellow paint clamps purchased from Home Depot for $.00 each. The clamps are attached or bolted to a cheap scrubbing-pad purchased from Home Depot for $1.9. I then bought two 1 x /0 bolts and soldered them into the brass knurled-knobs I bought at Home depot. The assembly simply clamps onto my pack waist belt.

5 Workman 0m -Band Mod.0 SWR.0 Blacktop SWR BlacTop SWR Workman 0m -Band Mod SWR Blacktop SWR

6 SWR Workman 0m -band BlackTop SWR