Re: [Repeater-Builder] DTMF controllable propane generators
R. D. Reese 330-329-8754 - Original Message - From: Robert Pease To: Repeater-Builder@yahoogroups.com Sent: Friday, May 09, 2008 2:59 PM Subject: RE: [Repeater-Builder] DTMF controllable propane generators depending on gas prices, you could get close to that in gas -- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Chuck Kelsey Sent: Friday, May 09, 2008 2:54 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] DTMF controllable propane generators Be happy having a club to help spread the cost out. I pay $45 a month for electric to sustain two repeaters at one of my sites. In order to keep the site, I had to purchase a chunk of the land and build a building, so now there's real property taxes and maintenance to pay as well. And all the equipment is at my expense. And there are others I know doing pretty much the same thing. No club -- it's all out of pocket. Like I said, be happy you've got cost sharing. Chuck WB2EDV - Original Message - $30 to $50 a month electricity bill is a significant chunk of the clubs annual revenues. We do have money in the bank though. But these are all the kinds of numbers we are running through right now to figure out the best options. Tony Since 1974, the award-winning Alpert JFCS has helped families of all faiths throughout most of Palm Beach County, FL, via counseling, seniors services, residences for the disabled, mentoring children, support groups and a lot more. SOLUTIONS FOR LIVING (R) www.JFCSonline.com Please take note of our new website and E-Mail Addresses. Please update your contacts ASAP. NOTICE: This e-mail message and all attachments transmitted with it are intended solely for the use of the addressee and may contain legally privileged and confidential information. If the reader of this message is not the intended recipient, or an employee or agent responsible for delivering this message to the intended recipient, you are hereby notified that any dissemination, distribution, copying, or other use of this message or its attachments is strictly prohibited. If you have received this message in error, please notify the sender immediately by replying to this message and please delete it from your computer. No virus found in this outgoing message Checked by PC Tools AntiVirus (4.0.0.26 - 10.072.011). http://www.pctools.com/free-antivirus/
FW: [Repeater-Builder] DTMF controllable propane generators
the gasifiction depends to a large extent on the mix , unless pure propane I think you might be in for a surprise , if you know a good motor engineer ) we have one in another group) then I suggest you take advice about the matter as there are ways to make it work. To: Repeater-Builder@yahoogroups.com From: [EMAIL PROTECTED] Date: Thu, 8 May 2008 22:55:23 -0600 Subject: [Repeater-Builder] DTMF controllable propane generators Folks We're moving a VHF MSR2000 repeater and two UHF GMR300 linking radso's to a site where commercial power will cost $5000 plus monthly fees. So we're looking at various options such as solar, wind and so forth. The land owner might not appreciate another wind turbine so one idea we're thinking about is a DTMF controlled propane generator. Has anyone experimented with such? I see mention of remote control generators so figure it should be doable. The current controller is a RLC-3 but that could be changed if it would help. The other obvious answer is to have the generator automatically come on when the voltage gets too low but I wonder how well that will work. We're in central Alberta, Canada so the days in winter are quite short and we can get 20 or 25 cloudy days in a row. We either need to put in a *lot* of solar panels or some other form of auxiliary power. Also the site may be accessible only by snowmobile for a number of months in the winter.We also will have to ensure that if the temperature looks like it's going to get colder than -35 for an extended period of time we'd better have the batteries charged right up as propane won't gasify colder than that. Thanks, Tony _ Be part of history. Take part in Australia's first e-mail archive with Email Australia. http://emailaustralia.ninemsn.com.au
RE: [Repeater-Builder] DTMF controllable propane generators
Your solution may be easier than you think. By the time you get a generator, tank, controller of some sort, setup, fuel charges, and gen maintenance, not to mention going up the hill in the winter a few times to thaw the gen... $5000 one time then small monthly electric bill starts to sound cheap. Sometimes the answer isn't technical at all Rob. KS4EC Sent by Good Messaging (www.good.com) -Original Message- From: Tony VE6MVP [mailto:[EMAIL PROTECTED] Sent: Friday, May 09, 2008 12:56 AM Eastern Standard Time To: Repeater-Builder@yahoogroups.com Subject:[Repeater-Builder] DTMF controllable propane generators Folks We're moving a VHF MSR2000 repeater and two UHF GMR300 linking radso's to a site where commercial power will cost $5000 plus monthly fees. So we're looking at various options such as solar, wind and so forth. The land owner might not appreciate another wind turbine so one idea we're thinking about is a DTMF controlled propane generator. Has anyone experimented with such? I see mention of remote control generators so figure it should be doable. The current controller is a RLC-3 but that could be changed if it would help. The other obvious answer is to have the generator automatically come on when the voltage gets too low but I wonder how well that will work. We're in central Alberta, Canada so the days in winter are quite short and we can get 20 or 25 cloudy days in a row. We either need to put in a *lot* of solar panels or some other form of auxiliary power. Also the site may be accessible only by snowmobile for a number of months in the winter.We also will have to ensure that if the temperature looks like it's going to get colder than -35 for an extended period of time we'd better have the batteries charged right up as propane won't gasify colder than that. Thanks, Tony Since 1974, the award-winning Alpert JFCS has helped families of all faiths throughout most of Palm Beach County, FL, via counseling, seniors services, residences for the disabled, mentoring children, support groups and a lot more. SOLUTIONS FOR LIVING www.JFCSonline.com Please take note of our new website and E-Mail Addresses. Please update your contacts ASAP. NOTICE: This e-mail message and all attachments transmitted with it are intended solely for the use of the addressee and may contain legally privileged and confidential information. If the reader of this message is not the intended recipient, or an employee or agent responsible for delivering this message to the intended recipient, you are hereby notified that any dissemination, distribution, copying, or other use of this message or its attachments is strictly prohibited. If you have received this message in error, please notify the sender immediately by replying to this message and please delete it from your computer.
Re: [Repeater-Builder] DTMF controllable propane generators
Tony, Wonder why the commercial power would cost that much. Is it because of the wiring installation cost??? 73, ron, n9ee/r From: Tony VE6MVP [EMAIL PROTECTED] Date: 2008/05/08 Thu PM 11:55:23 CDT To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] DTMF controllable propane generators Folks We're moving a VHF MSR2000 repeater and two UHF GMR300 linking radso's toa site where commercial power will cost $5000 plus monthly fees. Sowe're looking at various options such as solar, wind and so forth. The land owner might not appreciate another wind turbine so one ideawe're thinking about is a DTMF controlled propane generator. Has anyone experimented with such? I see mention of remote controlgenerators so figure it should be doable. The current controller isa RLC-3 but that could be changed if it would help. The other obvious answer is to have the generator automatically come onwhen the voltage gets too low but I wonder how well that willwork. We're in central Alberta, Canada so the days in winter are quite shortand we can get 20 or 25 cloudy days in a row. We either need to putin a *lot* of solar panels or some other form of auxiliary power. Also the site may be accessible only by snowmobile for a number of monthsin the winter.We also will have to ensure that if thetemperature looks like it's going to get colder than -35 for an extendedperiod of time we'd better have the batteries charged right up as propanewon't gasify colder than that. Thanks, Tony Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome.
RE: [Repeater-Builder] DTMF controllable propane generators
that 5k is still 10x what a good scrounger can do the job for To: Repeater-Builder@yahoogroups.com From: [EMAIL PROTECTED] Date: Fri, 9 May 2008 07:38:27 -0400 Subject: RE: [Repeater-Builder] DTMF controllable propane generators Your solution may be easier than you think. By the time you get a generator, tank, controller of some sort, setup, fuel charges, and gen maintenance, not to mention going up the hill in the winter a few times to thaw the gen... $5000 one time then small monthly electric bill starts to sound cheap. Sometimes the answer isn't technical at all Rob. KS4EC Sent by Good Messaging (www.good.com) -Original Message- From: Tony VE6MVP [mailto:[EMAIL PROTECTED] Sent: Friday, May 09, 2008 12:56 AM Eastern Standard Time To: Repeater-Builder@yahoogroups.com Subject:[Repeater-Builder] DTMF controllable propane generators Folks We're moving a VHF MSR2000 repeater and two UHF GMR300 linking radso's to a site where commercial power will cost $5000 plus monthly fees. So we're looking at various options such as solar, wind and so forth. The land owner might not appreciate another wind turbine so one idea we're thinking about is a DTMF controlled propane generator. Has anyone experimented with such? I see mention of remote control generators so figure it should be doable. The current controller is a RLC-3 but that could be changed if it would help. The other obvious answer is to have the generator automatically come on when the voltage gets too low but I wonder how well that will work. We're in central Alberta, Canada so the days in winter are quite short and we can get 20 or 25 cloudy days in a row. We either need to put in a *lot* of solar panels or some other form of auxiliary power. Also the site may be accessible only by snowmobile for a number of months in the winter.We also will have to ensure that if the temperature looks like it's going to get colder than -35 for an extended period of time we'd better have the batteries charged right up as propane won't gasify colder than that. Thanks, Tony Since 1974, the award-winning Alpert JFCS has helped families of all faiths throughout most of Palm Beach County, FL, via counseling, seniors services, residences for the disabled, mentoring children, support groups and a lot more. SOLUTIONS FOR LIVING (R) www.JFCSonline.com Please take note of our new website and E-Mail Addresses. Please update your contacts ASAP. NOTICE: This e-mail message and all attachments transmitted with it are intended solely for the use of the addressee and may contain legally privileged and confidential information. If the reader of this message is not the intended recipient, or an employee or agent responsible for delivering this message to the intended recipient, you are hereby notified that any dissemination, distribution, copying, or other use of this message or its attachments is strictly prohibited. If you have received this message in error, please notify the sender immediately by replying to this message and please delete it from your computer. _ Search for local singles online @ Lavalife - Click here http://a.ninemsn.com.au/b.aspx?URL=http%3A%2F%2Flavalife9%2Eninemsn%2Ecom%2Eau%2Fclickthru%2Fclickthru%2Eact%3Fid%3Dninemsn%26context%3Dan99%26locale%3Den%5FAU%26a%3D30290_t=764581033_r=email_taglines_Search_OCT07_m=EXT
RE: [Repeater-Builder] DTMF controllable propane generators
discussing this with a motor engineer who really knows about lpg/propane this was his response How far below ground level do you need to go to get away from the atmospheric temperature variation? Enough distance below ground with an insulated door will see a temperature consistently over 0C. If it's on a hill, go part way down the side of the hill and do a horizontal bore shaft and put the tank in the end of the shaft or a small carved room if in rock. The shaft only needs to be big enough to crawl into or for the diameter of the tank, whichever is larger. If the ground is unstable, large diameter concrete drain pipes can be used to form the shaft. All of the pipework including the outlet of the relief should be piped away in hose, with lagging if necessary. The idea is to make sure that cooling such as from conduction of heat away along the lines does not exceed the rate at which heat in the ground is able to transfer into the tank to maintain a consistent off temperature. Is it going to be liquid withdrawal or vapour? Small engines will be vapour, while bigger ones will be liquid. The difference is important because it affects the rate of tank cooling while the genset is running. In a vapour withdrawal system, the liquid in the tank is continually boiling off to maintain vapour pressure and the latent heat of vaporisation of that has to be compensated for by heat going into the tank from outside. Liquid withdrawal has a proportionally smaller rate of vapourisation relative to rate of fuel withdrawal as it only has to vapourise a quantity of liquid proportional to the liquid withdrawal to maintain vapour pressure. In a vapour withdrawal system, you'd virtually have to heat the tank from the waste heat (not exhaust) of the genset. With liquid withdrawal, the majority of the latent heat of vapourisation is handled in the convertor at the engine. An engine oil cooler under the tank would be an effective form of heating, but might need a pair of bypass thermostats, one to stop excessively cold flow and another to stop excessive heating of the tank... hope that helps To: Repeater-Builder@yahoogroups.com From: [EMAIL PROTECTED] Date: Fri, 9 May 2008 07:34:05 -0500 Subject: Re: [Repeater-Builder] DTMF controllable propane generators Tony, Wonder why the commercial power would cost that much. Is it because of the wiring installation cost??? 73, ron, n9ee/r From: Tony VE6MVP [EMAIL PROTECTED] Date: 2008/05/08 Thu PM 11:55:23 CDT To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] DTMF controllable propane generators Folks We're moving a VHF MSR2000 repeater and two UHF GMR300 linking radso's toa site where commercial power will cost $5000 plus monthly fees. Sowe're looking at various options such as solar, wind and so forth. The land owner might not appreciate another wind turbine so one ideawe're thinking about is a DTMF controlled propane generator. Has anyone experimented with such? I see mention of remote controlgenerators so figure it should be doable. The current controller isa RLC-3 but that could be changed if it would help. The other obvious answer is to have the generator automatically come onwhen the voltage gets too low but I wonder how well that willwork. We're in central Alberta, Canada so the days in winter are quite shortand we can get 20 or 25 cloudy days in a row. We either need to putin a *lot* of solar panels or some other form of auxiliary power. Also the site may be accessible only by snowmobile for a number of monthsin the winter.We also will have to ensure that if thetemperature looks like it's going to get colder than -35 for an extendedperiod of time we'd better have the batteries charged right up as propanewon't gasify colder than that. Thanks, Tony Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome. _ Be part of history. Take part in Australia's first e-mail archive with Email Australia. http://emailaustralia.ninemsn.com.au
Re: [Repeater-Builder] DTMF controllable propane generators
At 21:55 5/8/2008, Tony VE6MVP wrote: We're in central Alberta, Canada so the days in winter are quite short and we can get 20 or 25 cloudy days in a row. We either need to put in a *lot* of solar panels or some other form of auxiliary power. Also the site may be accessible only by snowmobile for a number of months in the winter. Gee, sounds like a slam dunk for nuc to me -- Dave Gomberg, San Francisco NE5EE gomberg1 at wcf dot com All addresses, phones, etc. at http://www.wcf.com/ham/info.html -
RE: [Repeater-Builder] DTMF controllable propane generators
At 07:38 AM 2008-05-09 -0400, Robert Pease wrote: Your solution may be easier than you think. By the time you get a generator, tank, controller of some sort, setup, fuel charges, and gen maintenance, not to mention going up the hill in the winter a few times to thaw the gen... $5000 one time then small monthly electric bill starts to sound cheap. Sometimes the answer isn't technical at all $30 to $50 a month electricity bill is a significant chunk of the clubs annual revenues. We do have money in the bank though. But these are all the kinds of numbers we are running through right now to figure out the best options. Tony
Re: [Repeater-Builder] DTMF controllable propane generators
Be happy having a club to help spread the cost out. I pay $45 a month for electric to sustain two repeaters at one of my sites. In order to keep the site, I had to purchase a chunk of the land and build a building, so now there's real property taxes and maintenance to pay as well. And all the equipment is at my expense. And there are others I know doing pretty much the same thing. No club -- it's all out of pocket. Like I said, be happy you've got cost sharing. Chuck WB2EDV - Original Message - $30 to $50 a month electricity bill is a significant chunk of the clubs annual revenues. We do have money in the bank though. But these are all the kinds of numbers we are running through right now to figure out the best options. Tony
RE: [Repeater-Builder] DTMF controllable propane generators
depending on gas prices, you could get close to that in gas From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Chuck Kelsey Sent: Friday, May 09, 2008 2:54 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] DTMF controllable propane generators Be happy having a club to help spread the cost out. I pay $45 a month for electric to sustain two repeaters at one of my sites. In order to keep the site, I had to purchase a chunk of the land and build a building, so now there's real property taxes and maintenance to pay as well. And all the equipment is at my expense. And there are others I know doing pretty much the same thing. No club -- it's all out of pocket. Like I said, be happy you've got cost sharing. Chuck WB2EDV - Original Message - $30 to $50 a month electricity bill is a significant chunk of the clubs annual revenues. We do have money in the bank though. But these are all the kinds of numbers we are running through right now to figure out the best options. Tony Since 1974, the award-winning Alpert JFCS has helped families of all faiths throughout most of Palm Beach County, FL, via counseling, seniors services, residences for the disabled, mentoring children, support groups and a lot more. SOLUTIONS FOR LIVING www.JFCSonline.com Please take note of our new website and E-Mail Addresses. Please update your contacts ASAP. NOTICE: This e-mail message and all attachments transmitted with it are intended solely for the use of the addressee and may contain legally privileged and confidential information. If the reader of this message is not the intended recipient, or an employee or agent responsible for delivering this message to the intended recipient, you are hereby notified that any dissemination, distribution, copying, or other use of this message or its attachments is strictly prohibited. If you have received this message in error, please notify the sender immediately by replying to this message and please delete it from your computer.
Re: [Repeater-Builder] DTMF controllable propane generators
Tony, Why DTMF controlled? If the batteries run down because no one starts the generator, you'll be unable to start it remotely, and have to go to the site. Use a repeater controller which has enough smarts to monitor the system, start and stop the generator automatically, page someone when there's a problem, and provide a DTMF override of the automatic functions if needed. How secure is your site? A generator and fuel supply could be attractive resale opportunities for meth addicts. Then again, so might solar panels or a wind turbine. You haven't mentioned how your site is laid out, or how much space you have, but wind may be a good alternative. If you determine a realistic power budget, you might be surprised at how small a wind turbine would keep the site up. With enough reserve battery capacity and a repeater controller programmed to load-shed by reducing power when things get tight, much can be done. A few months ago, I looked into small turbines, and found one designed for portable use by motor home owners. It had blades about 1.3m in diameter, and IIRC would be capable of 200+ watts continuous in a 15 mph wind. A hybrid system with wind and solar can reduce the needed turbine size even more. Although, if you get below about 600 watts, wind turbines start looking more and more like toys. I'm guessing a wind generator made for occasional use on a sailboat mast wouldn't last the winter in Alberta. The MSR2000 may not be the best candidate for alternative power, since its idle current draw will be significant, and reducing transmitter power will not produce a proportionate drop in current consumption. I'd guess the GMR300s also have relatively high idle current. I once ran a UHF repeater using Repco RFID data boards. The 2-watt transmitter drew 750 mA at 13.8 VDC when transmitting; the receiver drew 24 mA at idle. The S-Com 7K's 100 mA drain turned out to be the biggest item in my power budget, even after I added a Motrac helical preselector to the receiver. I used a single, 42-watt (@ 14V) solar panel and a 100 AH marine deep cycle battery, which would have allowed continuous key-down operation for over four days with no sun. At 200', it was a very useful repeater for downtown public service events, and even rag-chewing among suburbs. I built a crude solar regulator with a relay which latched to take the panel offline when the system voltage reached 14.4V for the first time each day. Since the relay coil was powered by the panel, it automatically dropped and reset at sunset. A logic input on the 7K sensed the latching of the relay, and would send a DTMF burst decoded remotely to track what time each day the system reached full charge. (Usually mid-morning.) The macro fired by that logic input also altered the courtesy beep and lengthened the repeater's tail, so I could determine the regulator's relay status even if I missed the daily status page. At sunset, the dropping relay sent another DTMF page, and the courtesy tones and tail time reverted to their night mode. A logic output from the 7K was connected to momentarily unlatch the relay, in case I wanted to remotely start a second daily charge cycle in the afternoon. With 4+ days of battery backup, I never needed to do so, but it was nice to know I could always top off the battery the afternoon before a hurricane was coming, etc. But, alas, FM land mobile users don't like weak signal work, and I eventually bit the bullet and went to a GE Mastr II and AC power. You may also find, as others are suggesting, that commercial AC mains with battery backup is the most cost-effective option in a practical system. Paul, AE4KR - Original Message - From: Tony VE6MVP To: Repeater-Builder@yahoogroups.com Sent: Thursday, May 08, 2008 10:55 PM Subject: [Repeater-Builder] DTMF controllable propane generators Folks We're moving a VHF MSR2000 repeater and two UHF GMR300 linking radso's to a site where commercial power will cost $5000 plus monthly fees. So we're looking at various options such as solar, wind and so forth. The land owner might not appreciate another wind turbine so one idea we're thinking about is a DTMF controlled propane generator. Has anyone experimented with such? I see mention of remote control generators so figure it should be doable. The current controller is a RLC-3 but that could be changed if it would help. The other obvious answer is to have the generator automatically come on when the voltage gets too low but I wonder how well that will work. We're in central Alberta, Canada so the days in winter are quite short and we can get 20 or 25 cloudy days in a row. We either need to put in a *lot* of solar panels or some other form of auxiliary power. Also the site may be accessible only by snowmobile for a number of months in the winter.We also will have to ensure that if the temperature looks like it's going to get colder than -35
Re: [Repeater-Builder] DTMF controllable propane generators
At 01:55 PM 2008-05-09 -0600, Paul Plack wrote: Why DTMF controlled? If the batteries run down because no one starts the generator, you'll be unable to start it remotely, and have to go to the site. Use a repeater controller which has enough smarts to monitor the system, start and stop the generator automatically, page someone when there's a problem, and provide a DTMF override of the automatic functions if needed. I'm not at all sure if that's a good enough solution. Which is why I'm asking. Also if we see the batteries are getting down a bit but that the forecast is for five days of sunshine then there is no need to run the generator. So I'm not sure I want an automatic solution. I also realize that the more you use the batteries and the lower you drain them the shorter the battery life. That is draining a battery right down once shortens a battery life much more than draining a battery 1% 100 times. How secure is your site? A generator and fuel supply could be attractive resale opportunities for meth addicts. Then again, so might solar panels or a wind turbine. It's reasonably remote.At least an hours drive from the nearest city. Ten minutes from the nearest town. Lots of gravel roads which won't deter such but this hasn't been a problem out in rural Alberta. You haven't mentioned how your site is laid out, or how much space you have, but wind may be a good alternative. If you determine a realistic power budget, you might be surprised at how small a wind turbine would keep the site up. With enough reserve battery capacity and a repeater controller programmed to load-shed by reducing power when things get tight, much can be done. A few months ago, I looked into small turbines, and found one designed for portable use by motor home owners. It had blades about 1.3m in diameter, and IIRC would be capable of 200+ watts continuous in a 15 mph wind. My initial posting mentions that the owner of the tower felt that the land owner wouldn't like another wind turbine on the site. The MSR2000 may not be the best candidate for alternative power, since its idle current draw will be significant, and reducing transmitter power will not produce a proportionate drop in current consumption. I'd guess the GMR300s also have relatively high idle current. Yes, we're looking at that as well. One suggestion was to look at Daniels MT-2 Series repeaters. Not sure what would be suitable alternatives for the UHF linking radios but we'll consider all suggestions. smile Interesting ideas snipped. But, alas, FM land mobile users don't like weak signal work, and I eventually bit the bullet and went to a GE Mastr II and AC power. You may also find, as others are suggesting, that commercial AC mains with battery backup is the most cost-effective option in a practical system. This will be the only repeater covering a fair bit of the terrain with some overlap at the edges. I'm not quite sure just how much difference 5 watts output vs 100 watts will make. I'll let the other guy who understands the modelling a lot better than I do generate the coverage maps. And about half the activity is due to mobile users such as truckers as this repeater covers a chunk of a major highway. Tony
Re: [Repeater-Builder] DTMF controllable propane generators
Tony VE6MVP wrote: This will be the only repeater covering a fair bit of the terrain with some overlap at the edges. I'm not quite sure just how much difference 5 watts output vs 100 watts will make. Why not do the math? :-) C'mon. It's not a secret. Nothing hard about it. Start at the transmitter... power level. You got that part. Now work your way to the other end of the RF system, the mobile user... Find out these items: Feedline loss at the site from the transmitter to the isolator. Loss through the isolator, duplexer and any necessary filters. Loss through the feedline from the filter system to the antenna, including any accessories like lightning protection and/or connectors. Antenna gain in dBd or dBi. Antenna height above average terrain, and a bit of knowledge about what terrain features block your signal to various places you want to cover, or otherwise know you can't cover. Free-space path loss at your chosen frequency of operation. Typical user's antenna gain and feedline losses. Once you have all of that... you can tell a lot of things. One of the FIRST things you learn by documenting all of that stuff is what power levels you SHOULD be seeing at each test point, even so far as hooking a wattmeter right below your antenna and reading it there... if the numbers don't match, check your assumptions, or something is broken. (In other words, how can you KNOW your system is working if you don't have the above numbers committed to an RF engineering book for each repeater? Do it right. Write it all down. Keep a copy of the engineering book on-site, too.) I'll let the other guy who understands the modelling a lot better than I do generate the coverage maps. Models are only as smart as the person who wrote them and the guy driving the modeling software. :-) And about half the activity is due to mobile users such as truckers as this repeater covers a chunk of a major highway. Not sure what this has to do with the RF performance, other than you're saying that you at least know what kind of rigs and antennas they typically use, and their usual routes within the repeater's coverage area (highways and truck stops). So you know a little about what your users will be like and what they want. That's good. :-) But not related to getting the maximum possible performance out of your system within any design limitations (like power utilization). Now... if you DO all of that homework, you'll often find for mountaintop sites that altitude trumps power, and antenna gain trumps all... it's just basic RF physics. We have a site at 11,440' MSL that's about 5500' HAAT, and if we lose a PA, it generally loses some coverage, but the repeater is still copyable by mobile users 80+ miles out... it's just not as strong as it usually is. In closer, there will be users who are using outside antennas (not rubber ducks) who didn't notice the repeater dropped from 12W out the antenna to less than a watt. Mobile users will notice because when they're in areas where the repeater was weak before, it may drop out completely... which will just make the repeater sound fluttery as they move. And if the mobile users are out where they're away from obstructions and things that cause the weak spots, the repeater that was full-scale on their receivers, will now be a couple of S-Units less. They'll only notice that the S-Meter went down and maybe some slight additional white noise... since FM receivers aren't very linear about how they receive weak signals. This all assumes you have at least some decent level of antenna gain. Without antenna gain, you need power to make up for the inefficiency in the antenna's ability to get a signal to your users. In the end it comes to these priorities... - Best antenna possible. - Altitude, altitude, altitude. - Best receiver possible at the repeater (sensitivity and selectivity) - Low loss feedline, best filtering system possible (low loss but filters what's needed to be filtered) And then.. oh yeah, throw some power at it with a PA after all that above works, and balance the system for whatever users you are shooting for... mobiles, HT's with rubber ducks, whatever... S many beginning repeater folks buy decent repeater gear, but... They don't buy good filters, don't buy pre-amps or anything to assist the receiver, don't buy good feedline, and don't protect their investment with lightning protection, etc... The poor repeater antenna is often a complete afterthought. Which is strange. The same guy who decided to put up a repeater might have an entire FARM of antennas for his HF part of the hobby, but it doesn't dawn on him that the antenna will make or break his repeater... And if you talk to him while he's building his first repeater, he's usually worried about power output before all else. Money spent getting the repeater higher (sounds like you guys have already done that part) with the
[Repeater-Builder] DTMF controllable propane generators
Folks We're moving a VHF MSR2000 repeater and two UHF GMR300 linking radso's to a site where commercial power will cost $5000 plus monthly fees. So we're looking at various options such as solar, wind and so forth. The land owner might not appreciate another wind turbine so one idea we're thinking about is a DTMF controlled propane generator. Has anyone experimented with such? I see mention of remote control generators so figure it should be doable. The current controller is a RLC-3 but that could be changed if it would help. The other obvious answer is to have the generator automatically come on when the voltage gets too low but I wonder how well that will work. We're in central Alberta, Canada so the days in winter are quite short and we can get 20 or 25 cloudy days in a row. We either need to put in a *lot* of solar panels or some other form of auxiliary power. Also the site may be accessible only by snowmobile for a number of months in the winter.We also will have to ensure that if the temperature looks like it's going to get colder than -35 for an extended period of time we'd better have the batteries charged right up as propane won't gasify colder than that. Thanks, Tony
