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eHam Forums / Elmers / Mosely TA33 Traps
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on: February 24, 2003, 08:59:30 AM
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I have a 33 jr that I picked up second hand and took to a field day after being warned about the insect nesting and shorting - it had bugs and we cleaned them out. It took me another year to get my tower prepared and for the fun of it I examined one of the traps before hoisting the antenna, I found them filled again. I dismantled each one and coated the coils with insulation varnish from a motor rewinding company, there are places where you can purchase this in spray cans, ask someone in a local club who works industrial electrical maintenance about obtaining some for you.
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2
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eHam Forums / Elmers / Repeater Class
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on: February 24, 2003, 08:49:01 AM
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Glad to see your interest in the hobby, there are so many things to do with wireless. You might know and have probably read about this being a well traveled method for packet operations, many university clubs have something like this going. Once you get licensed you will want to aquire a continuous (read larger frame and heat sink) duty style radio set for the band of your choice, this is mostly done by tuning commercial hand me downs into the ham bands as they have the heat sink quality to run for long periods without burning out the final amplifier compnents. interfacing the data feed in place of the microphone and speaker is as easy as making a replacement cable for the radio set of your choice, the more difficult part is getting a antenna mounted in a place where access can be attained by portable operators - these often leads to roof access on campuses and becoming familiar with building maintenance staff meetings so that any wiring gets sealed well and doesn't lead to your equipment being disconnected and packed off to the corner. I will say welcome to the hobby in advance, whether you are doing this with windowz or linux variants you will quickly make friends experimenting with the system.
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3
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eHam Forums / Elmers / ground- coupled
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on: February 24, 2003, 08:32:58 AM
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I wanted to add a point about grounding as I see so many operators wondering about that third wire on the electrical outlet. Working as an electrician I see this problem often, using an electrical tester to determine the electrical ground was secure where the electrical power outlet is located. This has little if anything to do with RF grounding and should not be used as a RF ground, for power supplies yes, radio no. What happens is you are using the internal house wiring as your counterpoise, in the absence of a RF ground the stray RF travels along the internal wiring back to the electrical load center and may well continue out where ever if decides to go, dishwasher controls, clock radio, television set. I am mostly called into these scenarios when the home security system goes wacko and sends false alarms, fire or CO signal out to the station. How to fix - get a RF ground to the coax switch, transmitter or antenna base, this will be a 8 ft 5/8 ground rod driven below grade or the soil line, most installations of this rod are 24 inches away from the foundation to prevent rupturing the foundation drain pipes, connect green covered or bare wire at least 12awg to your station components, this can be buried till you reach the cement wall and looks nice if secured with grommets - seal the insects out where you go into the house. This wire should be continuous to the station area, no splices - none are permitted per NEC - however obstacles arise and variances are determined on a case by case study by the authority having jurisdiction in your area. Some home improvement stores that stock electrical panels also have the grounding bars that can be fitted into the older 14 inch wide panels that weren't originally equipped for grounding, these make nice station connect points if you mount this underneath your operating table you can run short wires to your components easily. If the RFI persists once you have your station ground secure then you are flooding something with near field radiation and will have to solve that one device at a time with ferrite beads or covering the openings on appliances with grounded tin foil and probably then follow with aluminum window screen segments as a more permanent solution.
Hailing from NOARS Country, 73...Clark Beckman N8PZD
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eHam Forums / Elmers / Grounding on the second floor
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on: February 24, 2003, 08:25:32 AM
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Working as an electrician I see this problem often, using an electrical tester to determine the electrical ground was secure where the electrical power outlet is located. This has little if anything to do with RF grounding and should not be used as a RF ground, for power supplies yes, radio no. What happens is you are using the internal house wiring as your counterpoise, in the absence of a RF ground the stray RF travels along the internal wiring back to the electrical load center and may well continue out where ever if decides to go, dishwasher controls, clock radio, television set. I am mostly called into these scenarios when the home security system goes wacko and sends false alarms, fire or CO signal out to the station. How to fix - get a RF ground to the coax switch, transmitter or antenna base, this will be a 8 ft 5/8 ground rod driven below grade or the soil line, most installations of this rod are 24 inches away from the foundation to prevent rupturing the foundation drain pipes, connect green covered or bare wire at least 12awg to your station components, this can be buried till you reach the cement wall and looks nice if secured with grommets - seal the insects out where you go into the house. This wire should be continuous to the station area, no splices - none are permitted per NEC - however obstacles arise and variances are determined on a case by case study by the authority having jurisdiction in your area. Some home improvement stores that stock electrical panels also have the grounding bars that can be fitted into the older 14 inch wide panels that weren't originally equipped for grounding, these make nice station connect points if you mount this underneath your operating table you can run short wires to your components easily. If the RFI persists once you have your station ground secure then you are flooding something with near field radiation and will have to solve that one device at a time with ferrite beads or covering the openings on appliances with grounded tin foil and probably then follow with aluminum window screen segments as a more permanent solution.
Hailing from NOARS Country, 73...Clark Beckman N8PZD
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eHam Forums / Elmers / 250b on 70cm
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on: February 22, 2003, 07:03:56 PM
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Here is something to look for at hamfests as a building block, GE used to have uhf transmitters with tube finals, the master-pro series - I am converting our old repeater one to 4cx250 for 6 mtrs. If you visit a 2way shop and tell them of your aspirations to build this they may take you around back and beg you to get it outa here. If you have to bring a few dozen doughnuts back to get the service manuals it would be a good investment because these books are going for 30-50 bux on ebay. My geographical area has used a large portion of the band with repeater links so the ATV crowd has migrated to 1.2, do some filtering research and make a tripler.
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6
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eHam Forums / HomeBrew / I need help designing 2 ele beam !!
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on: February 22, 2003, 06:47:09 PM
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I don't know about the buddipole specifically however I have spent several years designing, contructing and testing vhf/uhf antennas, the second element will be much more effective as a reflector. There are many possibilities going thru my mind about how you will get forward gain, each one has its own distinct advantages and drawbacks, you have many resources if you are able to search on-line and do some paper and computer modeling before you narrow the design down and purchase materials.
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7
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eHam Forums / Clubs / Club Call Usage
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on: February 22, 2003, 06:38:50 PM
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For a few years I used the club callsign from my house while in january vhf contest - it was too cold to go to our field day site for the contest - we tried it once and with 3 torpedo heaters running you could still see your breath when you spoke. That year several of us made voice chip microphone bases so we didn't have to bark out the club call over and over, but the chill from the hill remained so every other contest I use the club callsign from my home until younger blood flows in and carries the torch. The club takes some publicity and answers the qsl cards, I get the rocking chair and the pillowstack is just a walk down the hallway.
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8
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eHam Forums / Elmers / Phone Patch
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on: February 22, 2003, 06:22:30 PM
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I think we have a candidate for ham radio licensing here guys and gals, solving the overall coverage distance would require joining a few area club with phone patch repeaters that cover the area. One thing about using a club/repeater autopatch is most controllers have a 3 minute phone time-out, however if your xyl became licensed the talk time would be on-the-air instead of phone patching and the possibilities are endless. If you were to try and set this system up using cb's as I think I extracted from the summary reply, you will have limited success transmitting the dtmf tones to the controller, in fact I think band noise in general would become an obsticle as the cb's use am instead of fm. Former airwave pirate, learned a lot tinkering in the hobby and hailing from NOARS Country, 73...Clark Beckman N8PZD
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eHam Forums / Elmers / Urban VHF range without using a repeater.
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on: February 22, 2003, 06:02:36 PM
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Well, I would recommend this person go to a ham radio club is his area and find out what is being used by those that do it often. While he/she is there maybe ask what is involved in becoming licensed, if you have 100 watt uhf radios you can't use them in gmrs service anyway - ham radio is the best place for that power level. That is more than a plug for ham radio, really you might be able to use them in commercial service but the licensing costs there climb steeply and you only have a couple years to convert to narrowband equipment which might explain how you found yourself with 100 watt uhf stuff. Check them out carefully before you buy, you can learn a lot thru searching on-line. There will be plenty more uhf radios hitting the hamfests over the next few years as those who stay on-the-air make the conversions, average price currently is about a buck a watt uhf and about half that for vhf, that may drop as the market gets flooded in 2 years. Hailing from NOARS Country, 73...Clark Beckman N8PZD
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eHam Forums / Elmers / More toroid winding questions
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on: February 20, 2003, 11:14:56 PM
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Enameled wire is used in transformer applications because it can be tightly packed against one another thereby yielding the highest magnetic flux or iron saturation, the thicker the insulation the wider the spacing will be resulting in larger iron or ferrite needed to create the flux. Some rf toroid core applications are spaced apart not to reduce the flux but to distribute the flux evenly. Also under consideration is the temperature rating where the insulation breaks down, when tightly packed the ability to disipate heat has disappeared, now the coils will short for certain. In the transformer application using plastic covered wire would lead to very short thermal cycle life, if you dare try this be certain to ground the iron frame to prevent taking a shock, also a good idea that is used in electrical labs is fusing the items seperately to prevent a project wipeout in the event of component failure.
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11
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eHam Forums / Elmers / Powering up old transmitter.
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on: February 20, 2003, 11:00:16 PM
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I like the idea of the light bulb in series with the ac line, however before you actually apply power to the radio at all use the light bulb under the chassis pan overnight to dry out all the components, especially those wax electrolytics - they are great for throwing hot waxy sparks out. If you are serious about this radio you might want to list them all and figure the cost of replacements, the wax can dry out thru thermal cycling and lead to an internal arc condition which then shows up as a wax leak - sometimes this may also flash a bright light show and a bit of purple haze shadowing the radio set. You will then need to make some replacements before proceeding.
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eHam Forums / Elmers / Running Coax Thru A Crawlspace
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on: February 18, 2003, 07:21:22 PM
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You should visit your library and get some ideas from the 2002 NEC article 800 covers communications, 810 radio and tv including amateur radio, article 300 will give you some ideas on methods of cabling. Basically exposed cabling is not a good idea, floors - tossed onto attic rafters - draped over gas and water lines, furnace piping is not only sloppy workmanship but also a potential safety problem because when the plastic covering is abraded thru the metal rf carrying part will be exposed to things that it shouldn't be like water pipes, gas lines and furnace ducting - anyone touching them will certainly wonder why it tingles so much. If you look at a home with over head electrical service try to make your outdoor run the same way, 2 inch plastic pipe with a weather cover and a large junction box going into the basement can all be painted to match the house before you secure it with straps - I would use a metal strap at the top in the event of heavy ice formations = lots of extra weight. Also attach a short stub of pipe to the box where you go into the house just far enough so you can see it and be certain you can add or subtract wires in the future, you dont need to continue the tubing unless it is easy, this area is where flexible conduit is used for load centers and the like but it is costly and hard to find in short lengths. If you are going to make individual runs, you will find that trade 16 or 3/4 inch is the smallest that the pl connector will pass thru, larger tubing will make it go around corners easier and allow double cableing if you out-grow the original idea - the extra expense is minimal - the fittings and boxes are the costly part. Of course use some caulking where you go into the basement to keep insects outside and also inside the box type fitting insert a couple plastic grocery sacks and a squirt of spray foam will make any future service much easier when the cables are clean, just pressing some foam padding in there would be the minimum to keep the insects out of the house. In the basement supporting segments of pipe to the cieling large enough to carry how ever many cables you are using is sufficient, once you minimize the abrasion risk by offering this support you can now allow up to 4 ft between pipes and the connection to the outside, or other connections, your installation may require a few 10 footers thru the crawl space. If you have an electrician in your local club he/she may be able to provide a little more insight to the details of warm forming corners, they may have samples of the parts I described to show you. 73...Clark Beckman N8PZD
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eHam Forums / Elmers / Slinky Antenna
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on: February 18, 2003, 10:12:16 AM
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The slinky is a great idea and a good antenna, if you are not afraid to experiment and can operate an antenna tuner you will have a lot of fun on hf from a cramped operating location. A friend of mine used one for about a year in her apartment without any balun, it was tough to get the coax end to solder onto the slinky so we found some crimp-splice connectors and hooked it together that way. Once the slinky was suspended, it was just a matter of tuning it - the first and only problem was near field radiation that made the tuner meter indicate false swr problems. To solve that I remembered many years ago I was at a field day site watching a fellow twisting the tuner knobs very slowly without watching the meter, after I sat down to help him log I learned he was blind and he showed me one of his operating tricks - when you get your radio on frequency you want to operate click the tuner selector until you hear the rushing noise in the headphones get loud, now slowly twist the other knobs while turning down the volume until you get the loudest rushing noise in the reciever. He asked me to look at the swr meter when he keyed down and it was 1.2-1, after awhile he moved to another band and did it again, amazing - he went to another part of the band and again, slowly twist the knobs. So if the meter needle is hopping all over the place place a postcard over it and use the noise method instead, I use this method when operating our club submarine station where it is hard to see anything with a crowd of observers inside the small radio shack. Hailing from NOARS Country, 73...Clark Beckman N8PZD
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eHam Forums / Elmers / Why are most SWR meters built like this?
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on: February 17, 2003, 09:36:37 AM
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If you would like to do the rough tuning, try this - ignore the meter face while clicking thru the selections until the rushing noise heard thru your headphones is loud, now twist the knobs slowly until you get the loudest rushing noise possible - take away the post card and examine your swr, there will be next to none - I learned this from a blind ham at field day many years ago and it works well in our club submarine station where the observers crowding makes it tough to see anything in the small shack. Of course you will have to trim it up when you change frequency but the noise will get you in the ballpark, and as I saw many times it will get you below 1.5-1 with no meter at all. Hailing from NOARS Country, 73...Clark beckman N8PZD
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eHam Forums / Elmers / The whole house hums
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on: February 17, 2003, 09:23:08 AM
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Working as an electrician I see this problem often, he used an electrical tester to determine the electrical ground was secure where the electrical power outlet is located. This has little if anything to do with rf grounding and should not be used as a rf ground, you are using the internal house wiring as your counterpoise, in the absense of a rf ground the stray rf travels along the internal wiring back to the electrical load center and may well continue out where ever if decides to go, dishwasher controls, clock radio, television set, I am mostly called into these scenarios when the home security system goes wacko and sends false alarms, fire or co signal out to the station. How to fix - get a rf ground to the coax switch, transmitter or antenna base, this will be a 8 ft 5/8 ground rod driven below grade or the soil line, most installations of this rod are 24 inches away from the foundation to prevent rupturing the foundation drain pipes, connect green or bare wire at least 12awg to your station components, this can be buried till you reach the cement wall and looks nice if secured with grommets - seal the insects out where you go into the house. Some home improvement stores that stock electrical panels also have the grounding bars that can be fitted into the 14 inch wide panels that werent originally equipped for grounding, if you mount this underneath you operating table you can run short wires to your components easily. If the rfi persists once you have your station ground secure then you are flooding something with near field radiation and will have to solve that one device at a time as mentioned with ferrite beads or covering the openings with grounded tin foil and probably then follow with aluminum window screen segments as a more permananent solution. Hailing from NOARS Country, 73...Clark Beckman N8PZD
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