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eHam Forums / Antennas and Towers and more / RE: Reusing Tower Base
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on: May 18, 2013, 07:15:51 AM
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A couple of hams I know tried cutting the tubes off close to the ground, grinding down the stubs flush with the concrete and grading over the concrete pad. Worked OK, until the weather chose to clear the dirt from on top of the pad.
I would suggest getting some grown sod and laying it over the concrete. At least the root system that the grass has developed will stop the covering from washing away, and you can cut down into the ground a little at the edges to even out the cover with the surrounding ground.
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18
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eHam Forums / HomeBrew / RE: 11m Tuner for 2m Antenna
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on: May 18, 2013, 06:23:28 AM
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Thanks for all the replies. I know it's a less than desirable setup, but I think it will be OK for what we will be doing....
...I have never built anything like this, how do I go about designing the circuit? How do I figure the needed component values?
Sorry, I don't know much, but I want to learn.
Sam, You say you want to learn, so you should listen. First, you need to use the antenna which would be the longer of the two. You simply cannot use a VHF antenna for 11 meter work--even with a tuning circuit--and expect it to work effectively. The CB won't transmit worth a darn--and may well be deaf as a stone to boot. Second, I suggested a simple cheap alternative, but if you're willing to spend money like you would for the Shakesphere antenna, you would be much better off using two four foot CB whips in a vertical dipole configuration in addition to the VHF antenna--something like one of the previous posters already said. That method would be by far the cheapest and the best of the two--including trying to build a matching circuit. One manufacturer even has a special bracket to connect two CB antennas up as a dipole, and hams do something similar with hamstick antennas. Eleven meters just isn't close to any multiple of the VHF frequencies you're specifying, and that is one thing that a dual band antenna should be for transmitting, even with tuning circuits. You end up straining one or both of the final sections of those transceivers--or blowing them out. Either that or if you do manage to get a close match, you will not transfer enough RF energy to the antenna to get any appreciable range. The solution you have your heart set on just is not practical, or when you get right down to it, workable.
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eHam Forums / HomeBrew / RE: Split audio for speaker and recorder
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on: May 18, 2013, 05:56:46 AM
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I suppose a 1kΩ resistor in series with the line to the mic input would do the trick.
That should indeed do it--in a rough and dirty manner. Just make sure you also have the speaker in the circuit if you do do it that way.
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20
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eHam Forums / Hamfests / RE: CARVED IN STONE???
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on: May 18, 2013, 05:53:38 AM
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Seems like all too many hamfests here in the states start early--and end early. Heck, one I went to I found quite by accident--at noontime on a Saturday. When I went to get a ticket, they let me in for free because they were already packing up! One guy said they had opened at 6 AM. Go figure!
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eHam Forums / Emergency Communications / RE: Inverter RFI
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on: May 18, 2013, 05:45:10 AM
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One thing you stated was (to me) a red flag right from the start. "Black & Decker." Ever since the brouhaha years ago about their fair trade practices, the one thing they've been known for is how they can sometimes cut corners. Just my opinion, but you should avoid most of their stuff like that inverter although their power tools are still pretty good. Of course, YMMV.
I believe Belkin has a small 100 watt inverter--just enough to run a laptop computer--that is said to be fairly noise free. I have a Delco-Remy inverter, 120 watts, that also does pretty well in the no noise department. Both these units plug into the cigarette lighter/power outlet sockets in a vehicle. Just my .02875 (inflation adjusted!) 73!
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23
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eHam Forums / Elmers / RE: Antenna cleaner
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on: May 18, 2013, 05:29:07 AM
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Yes, it seems like it could be used on antennas. I wouldn't rely on just that for antenna connections, however, and that stuff may have an adverse effect on other weatherproofing that you may want to use--in other words, the other weatherproofing may not 'stick' to the aluminum once you've coated it with the de-oxit. I'd check on that first.
Yes, the weatherguard finish is to be applied after the antenna is assembled. You could also use a clear coat spray--Krylon makes one. Or use other spray paints--to blend your antenna in with the surroundings. Just make sure that if you coat the entire antenna with the stuff that it isn't conductive. I believe the newer Krylon paints made for outdoor plastic furniture is ideal for that purpose. 73!
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eHam Forums / Antennas and Towers and more / RE: ARRL Antenna Book
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on: May 18, 2013, 05:18:41 AM
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I also agree. However, if there is a store near you that carries ARRL publications, you could pop in there and glance through the newest edition to see if there is anything that catches your eye, then get the book if there is.
I know that most of us either get ours through the mails directly, but if you can find a nearby store that carries ARRL materials, you can possibly save money by getting your stuff there. 73!
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eHam Forums / Antennas and Towers and more / RE: SWR problem
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on: May 18, 2013, 05:14:16 AM
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What are you using for a ground plane? In the manual for that antenna on one of the illustrations, it says "radials, if required." From your description here, it seems that is the problem--that radials are required at your installation.
Try a simple experiment. Take at 4 lengths of wire, 16 1/2 to 17 feet long. It can be covered (insulated) or bare wire, for this purpose one is as good as the other. Attach these wires to the ground point of the antenna at the antenna base, making sure the connections are good and tight, and stretch them out in opposite directions, 90 degrees apart. Now, go back in and check your SWR and tuning. If it has steadied and seems OK, you have a ground problem and need to lay out a radial field--because simply grounding the antenna isn't good enough.
You simply cannot use a connection to a ground rod for an RF ground, in almost all cases, an RF ground has to be a radial field even if your 1/4 wave vertical antenna paperwork says you don't need one. Also, even if the four radial wires seem to work OK, you'll be better off adding more radial wires, especially for the lower bends.
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eHam Forums / Antennas and Towers and more / RE: Unhooking Station Equipment Before A Thunderstorm
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on: May 18, 2013, 04:36:08 AM
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Not trying to be repetitious, but there are some things that should be kept in mind and considered. First, lightning protection is a matter of degree. If you go the way of professional installers at commercial sites, there are ways of protection that will eliminate just about any damage to the gear inside the building. Of course, that involves spending money--in some instances, a lot of money. For example, I know of sites where a well driller was called in to sink a well casing down to the water table to be used as a "ground rod". Other commercial sites rely on a ground halo around the building connected to multiple ground rods driven in along that halo. In any event, usually the ground systems of such sites cost more than what an average ham has in his shack in dollar value! Such sites may occasionally lose an antenna or have some minor hardware damaged, but little else happens to them, even if a direct strike occurs. You've got to ask yourself how much you think you need for protection, how much you're willing to spend--and how far you want to go to achieve what you're trying to achieve. It is possible to get near that 100% protection--if you're willing to go to the extremes that a commercial site does.
To the matter of equipment just sitting on a table or desk, the risk is no more or no less than to any other piece of electronic equipment in the building. Consider your television--it has a connection for an antenna. Having an antenna attached to it doesn't affect the risk unless a direct strike occurs or the ground system is either inadequate to begin with--or has been disconnected. A ground system should be robust enough to drain static charges and induced voltages at the very least--or it isn't much of a ground system. There are documented instances of a lightning strike coming down a conductor outside a building, then jumping to another conductor inside that same building, then outside again to find a ground point!
No matter what you may or may not do to protect your equipment, it could get damaged anyway. The best you can do is to take all the precautions you can--just as you seem to be doing. A monthly inspection of your station bulkhead/grounding panel and the ground connections will add to your peace of mind too--by making sure nobody has inadvertently tampered with or disconnected something that shouldn't have been tampered with to begin with. Such an inspection should be done immediately if any utility workers have visited your home for any reason, since there are instances of service personnel who have disconnected attached ground wires for odd reasons. 73!
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eHam Forums / Antennas and Towers and more / RE: electric winch for LG-70HD
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on: May 18, 2013, 03:55:18 AM
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In the way of discussion, I don't see what the difference would be--unless the tower was a nested crank up 'extension' type tower. As I read the specs of the LG-70HD, it is not one of those types. Could well be my error, but it seems that using a winch to raise the tower then securing the tower with other hardware will not leave the strain on the cable and winch itself. Even if a winch were used to raise an nested extension tower, only the foolhardy would leave the strain of supporting the tower on the winch drive for any extended length of time. On the cable, yes--that's unavoidable, but not directly on the worm gear drive. Seems to me that some way should exist to secure the cable drum so that can't happen. If it were my installation, I'd darn well find a way to do just that! As I said, I'm not trying to argue--I'm asking about it. I'm kind of in a learning curve here myself. 73! 
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eHam Forums / Emergency Communications / RE: UV-5R FOR PART 90 FIRE DEPT USAGE.
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on: May 16, 2013, 12:44:34 PM
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AS I've already said, Paul, there are grants available--especially with the interoperability issues being stressed by the government--for just about any department. What you just inferred--that you get what you can afford--is simply wrong, since the grants available (or even the used radios available) cost just as little as these Chinese wonder boxes you want to use.
All you're saying is that you--or whoever is in charge of the communications for that so called fire department--are unwilling to take the time and effort to go out and get the grants you need. You rather save yourself a bit of trouble and use equipment not suited to the rigors of the job its being used for, and since that may well include life safety (especially that of the individual firemen) that is not something you want to take chances with--at all.
Are you seriously saying that taking the time and trouble to get the best equipment available IS NOT WORTH A HUMAN LIFE???
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eHam Forums / Elmers / RE: A Brand New 100 Watt HF Transceiver For 400.00 ???
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on: May 16, 2013, 12:33:43 PM
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And here I thought this thread was supposed to be about a HF radio from the Chinese!
As with everything else, you get what you pay for. If there are complaints about those low price foreign made HF rigs that can be opened up for CB, I can't see what improvement these Chinese rigs would be--it seems that they would be the same type of garbage.
Hey, if you want one, there's a sucker born every minute--go get one. Just don't look for it to be type approved for the ham bands, it won't be.
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