------------------------- This antenna worked very well with a tuner and on 40m did not require a uner at all. Cut the 300 ohm ribbon cable (TV) to the same values as for a folded marconi. 5)160m Spider Web Disaster: This was one of those `Let's see what this old transformer winding wire can do' antennas. Although the antenna was pretty fair and I did talk to ennessee the antenna had a habbit of collecting odds and ends like palm frons,leaves, birds,branches,and these items caught the neighborhoods eye. "How is that branch hanging there?" "Is that bird hovering? My God he's dead!!" Needless to say,I took it down and the bird too. -WS --- GoldED 2.42.G1219 * Origin: VE3SJN....Moderator....HAM_TECH (1:163/506.4) --------------- FIDO MESSAGE AREA==> TOPIC: 188 HAM TECH Ref: EGU00015 Date: 12/25/97 From: ROB DENNIS Time: 12:42am \/To: ALL (Read 0 times) Subj: Wire Antennas Part 10 Original article from: Wayne Sarosi Reposted by Rob Dennis,Moderator HAM_TECH,for use of the FIDO HAM_TECH echo. THIS POST/SERIES NOT TO BE USED IN ANY CDROM COMPILATIONS FOR COMMERCIAL SALE WITHOUT EXPRESS WRITTEN PERMISSION OF ORIGINAL AUTHOR(S) OF THIS POST. ALL AND ANY COPYRIGHTS RETAINED BY AUTHOR(S). SUBJECT: Wire antennas - part 10 Let's wrap this up and start something new or finish something old like CP antennas. In anycase,the last part of this series is going to be devoted to wire antennas used on past field days,including all laughs and isappointments along the way. o Field Day 89,Draa Field,Titusville, FL. This was the field day of the Osprey. Draa field is a shared football field by the two high schools in Titusville. It has 50 foot tall bleachers,press box, and six 70 foot high lighting owers made out of cement. They also make excellent homes for Ospreys and indeed the one tower we needed was home to a new family of Ospreys. These are no slouch birds mind you,and don't take kindly to having a brave amateur climb the rebar ladder under their babies. We had to draw straws but our best climber got the job anyhow. What finally was placed up there was a pulley system to raise our 80 nverted Vee. This did rather well and was worth the effort and much to the disgust of the dive bombing and crying Ospreys. Too bad it rained the whole weekend. |-( But we did do the best TARC ever did,3700 points. Too bad the guy that was suppose to turn in the points never did. o Field Day 88,Draa Field,Titusville, FL. On this field day we used two of the lighting towers and strung out a full wave loop for 80 meters. Well... it wasn't quite high enough,and it wasn't in the right location,and it didn't do well...really poor...it sucked...and it rained all weekend. o Field Day 90,Complex 25,Cape Canaveral Air Force Station. We had two wire antennas; a 40m Inverted Vee taken from my tower here and using the mods I discussed earlier and a `field day' 80m `bow tie' antenna. The 40m worked fine and we copped more than 500 points on 40m, but the 80m was dismal. And it rained all weekend. o Field Day 91,Complex 25,Cape Canaveral Air Force Station. We dumped the bow tie and went with an Inverted Vee for both 80 and 40. Too bad 80 was so so as we worked only 200 points worth. But we had no problem reaching the Northeast and the Mississippi area. And it rained all weekend. o Field Day 92,Complex 25,Cape Canaveral Air Force Station. We had beams on most bands but the Inverted Vees worked fine again. This year we doubled our points and scored well in the 4000s working 4A. Next year they be a 40m yagi in operation. Look for K4FD,Kings 4 Field Day. BTW,it rained all day, ... again. o Field Day 93: 10m 3e Yagi,15m 3e Yagi,20m 3e Yagi,40m 2e Yagi,80m Inverted Vee,SAT,PACKET, see you on the air,I'll be on 20m. -WS --- GoldED 2.42.G1219 * Origin: VE3SJN....Moderator....HAM_TECH (1:163/506.4) --------------- FIDO MESSAGE AREA==> TOPIC: 188 HAM TECH Ref: EGU00016 Date: 12/25/97 From: ROB DENNIS Time: 12:43am \/To: ALL (Read 0 times) Subj: Towers Part 1 Original article from: Wayne Sarosi Reposted by Rob Dennis,Moderator HAM_TECH,for use of the FIDO HAM_TECH echo. THIS POST/SERIES NOT TO BE USED IN ANY CDROM COMPILATIONS FOR COMMERCIAL SALE WITHOUT EXPRESS WRITTEN PERMISSION OF ORIGINAL AUTHOR(S) OF THIS POST. ALL AND ANY COPYRIGHTS RETAINED BY AUTHOR(S). SUBJECT: Tower modifications for redistributing antenna windloads. Many Amateur Radio Operators are restricted to a maximum size antenna ecause of the limitations their towers have. The windload rating can cut a dream antenna in half because the tower is rated for something about the size of a ten meter beam. But,that's all you an afford so you take your lumps and settle for something less than you wanted. I had that problem and decided to do something about it. o I could purchase a larger tower. (BTW I finally had one given to me. It's still in the back yard). o Find a way to get the weight off the tower and on the ground. (Put the dynimite away!). Looking at the lastest ads,then looking in my wallet,then at my wife and ids then again at my 9-in triangular crank up and 22-ft beam,then back at my ife, I decided to to the latter of the two (gulp). How in the world was I going to relieve the weight from the tower and still keep my beam up at the same height? That 9-in trangular crank-up wasn't going to cut it in heavy winds. It was an accident waiting to happen. At that point I was working on my "I need a better tower" speech to my wife and remembered some of my statics and dynamics from college. I checked on a couple of examples in the book and found that my idea would work. The solution? A drive shaft/bearing modification. With the rotor moved to base of the tower and a vertical bearing set situated just above the otor. The rotor would have no downward thrust upon it. All it would have to do is turn the shaft. The bearings turned out to be easier then planned. Edmond Scientific Catalog had Lazy-Susan bearing sets for sale. I purchased the 1000-lb table type for about $6.50 each. After packing them in grease,I was ready to install them. The drive shaft can be a pair of push-up masts for crank-up towers or water pipe for fixed towers. The shaft is guyed within the tower by PVC tubing. Each tube is about 2-3 feet in length and I used three per forty feet. The shaft pokes out the top for antenna mounting. In my case,two sections of the push-up mast poked out the top allowing me to work and mount a few HF/UHF antennas. Here's the basic set-up: =================== 2m beam || || ====================================== HF beam || || |||| - PVC tubing over shaft inside tower |||| |||| |||| |||| |||| |||| |||| |||| |||| |||| |||| |||| |||| |BB| - Bearing |||| |RR| - Rotor location -------|--|-------- o The rotor only turns the shaft - no weight on the rotor. o The vertical weight is transformed to the bearing near the bottom. o The weight of the antennas are on the shaft instead of the tower. o The towers sole purpose is to guy the shaft and the forces directed to the tower are distributed along the tower's length. This system has been working here for over two years. -WS --- GoldED 2.42.G1219 * Origin: VE3SJN....Moderator....HAM_TECH (1:163/506.4) --------------- FIDO MESSAGE AREA==> TOPIC: 188 HAM TECH Ref: EGU00017 Date: 12/25/97 From: ROB DENNIS Time: 12:44am \/To: ALL (Read 0 times) Subj: Towers Part 2 Original article from: Wayne Sarosi Reposted by Rob Dennis,Moderator HAM_TECH,for use of the FIDO HAM_TECH echo. THIS POST/SERIES NOT TO BE USED IN ANY CDROM COMPILATIONS FOR COMMERCIAL SALE WITHOUT EXPRESS WRITTEN PERMISSION OF ORIGINAL AUTHOR(S) OF THIS POST. ALL AND ANY COPYRIGHTS RETAINED BY AUTHOR(S). SUBJECT: Towers,part two Towers are an interesting subject where antennas are concerned. We have the commercial types which can cost you a bundle. Then there are the cheap-o second (fifth) hand towers older than most hams, that we buy which,at best,offer a shakey support if not reworked properly. Antenna supports come in various flavors from trees,to push-up masts,to full blown,motorized,telescoping,hundred footers capable of leaping tall buildings in a single bound. All are good depending on what you use them for. A tower rated for 10 sq.ft windload should be adhered to order to save your equipment. An antenna and rotor system mounted on top of a a tower can put a heavy torque (twisting action) on the tower. Some towers and masts can't ake that torque and they crumble. There are ways to by-pass that problem and they will be discussed later. Guy lines can be a pain in the butt also. Metal guys can play havoc with various bands and ropes stretch. These will be looked into also. I reposted my first tower article based on some problems I have had here. I won't be able to cover everything but I have a few friends that have some interesting towers that I will share with you. AREAS TO BE COVERED: o Trees o Wooden towers o Push-up masts o Tubular towers o Small Steel Crank-ups (7 & 9-in tri-angulars) o Rohns o Commercial Grade o Monster Crank-ups o Roof mounts o Tilt-overs o Trouble spots -WS --- GoldED 2.42.G1219 * Origin: VE3SJN....Moderator....HAM_TECH (1:163/506.4) --------------- FIDO MESSAGE AREA==> TOPIC: 188 HAM TECH Ref: EGU00018 Date: 12/25/97 From: ROB DENNIS Time: 12:44am \/To: ALL (Read 0 times) Subj: Towers Part 3 Original article from: Wayne Sarosi Reposted by Rob Dennis,Moderator HAM_TECH,for use of the FIDO HAM_TECH echo. THIS POST/SERIES NOT TO BE USED IN ANY CDROM COMPILATIONS FOR COMMERCIAL SALE WITHOUT EXPRESS WRITTEN PERMISSION OF ORIGINAL AUTHOR(S) OF THIS POST. ALL AND ANY COPYRIGHTS RETAINED BY AUTHOR(S). SUBJECT: Tower Series,part 3 TREES: Trees have been used as antenna supports for years. There are some problems though. Trees grow,they have leaves or needles,they sway and are probably the greatest target for lightning than any man made device. I have used trees for an antenna support many times. In my CB days,I cut the top off an oak tree in Connecticut,35 feet up,and used chimney straps to hold a mast for a 'Starduster' quarter wave antenna. Here in Florida, I use a palm and a sycamore for a DX-A (40,80,& 160) and he same sycamore and a small maple for my 40 IVee. Both are fed from my tower. I have a pulley system to raise the antenna I need for specific operations. * sycamore ----------------------------------------- | | | | | | | |X tower | | |--------------------| | | | |------------------| * palm * maple <--------North Trees must be cared for when attaching support lines. Too tight and you can strangle the branch or worse, the tree. Never use a dead tree. They're an accident in the making. Beams in trees are not a good idea. Getting them up there is a pain in the butt to say the least save a crane. Constant upward growth interferes with he pattern and the ability to turn them thus requiring pruning. Pray you don't have a problem like bad SWR,bent elements,or a water soaked trap. I would suggest keeping trees for verticals or tie off points. ------------------------------------------------------------------ WOODEN TOWERS: These can be interesting. They are heavy,can rot,and don't stand much for he weather. Wooden towers are subject to many enemies such as bugs,birds,and rain. The sun can dry on out in two seasons. A wooden tower creaking in a 50 mph storm can give an amateur nightmares. They are expensive to build with todays pricing on wood. Simple fold-over wooden towers such as a flagpole design,can be done if the materials are availble at a resonable price. || || || || || || || || ||||||<--- pivot point |||||| |||||| ||||||<--- Locking pin (bolt) || || || || This set up can be done in a day with the right materials. The main pole can be pulled up with a pick-up or car. A stop bar is recommended so you don't pull the main section over with the vehicle. Place the stop bar just above he locking pin and bolt it into the main section but not the supports. It also can be cranked up with a boat winch from the bottom. -WS --- GoldED 2.42.G1219 * Origin: VE3SJN....Moderator....HAM_TECH (1:163/506.4) --------------- FIDO MESSAGE AREA==> TOPIC: 188 HAM TECH Ref: EGU00019 Date: 12/25/97 From: ROB DENNIS Time: 12:44am \/To: ALL (Read 0 times) Subj: Towers Part 4 Original article from: Wayne Sarosi Reposted by Rob Dennis,Moderator HAM_TECH,for use of the FIDO HAM_TECH echo. THIS POST/SERIES NOT TO BE USED IN ANY CDROM COMPILATIONS FOR COMMERCIAL SALE WITHOUT EXPRESS WRITTEN PERMISSION OF ORIGINAL AUTHOR(S) OF THIS POST. ALL AND ANY COPYRIGHTS RETAINED BY AUTHOR(S). SUBJECT: Tower Series,part 4 PUSH_UP MASTS: This is an inexpensive way to raise small HF beams,HF verticals and HF wire antennas. It is also a good support for VHF and UHF beams and omnis. The best push-up mast I have found for the money is the mast sold by Radio Shack. They may sell different brands of masts around the country,but the nes in Florida are excellent. The masts come with guy tie-off points at each section,cotter pin holes (change the pins out for bolts) and hand operated locking screws. Some of the good points are cost, ease of installation, easy care,and easy transport. They also make good tower drive-shafts. Some bad points,they can fold over in a storm with a beam on board,they are good lightning rods,once kinked,they're not worth a plug nickel. Overall,the push-up mast has probably made it to more field days than any other type of transported support in the history of ham radio. It's a good support that will last many years and serve the amateur well.