A useful primer for long-range satellite communication in a pandemic with minimal equipment.
Ah, doggone it, BG. Now I’m going to have to buy a dual-band hand-held rig, too…
Dennis and BG — Ive been trying to research an affordable ham radio rig that we could use for local communications, and maybe pull in info from beyond the region (new England). Would appreciate your advice on gear, etc. or point me to another thread where this has already been laid out. Many thanks. Over n out.
Dinkers,
I do not have extensive experience with a wide variety of ham radio gear and I do not currently subscribe to any amateur radio journals. My own rig is an ICOM 706 Mk II, capable of running a modest 100 watts on all HF bands (those generally used for long distance communication) and 20–50 watts on the VHF and UHF bands (those generally used for shorter distance communications). It operates on 12 volts. A full listing of the features may be found HERE. I purchased it, used, five years ago and had it mounted in my Suburban for several years, using it while traveling.
Others here (there are many licensed amateurs here) may have more options for you to consider. One suggestion is to go to a large bookstore and get the latest issue of the “QST” magazine and peruse the advertisements and reviews.
DIC, BG, and others
Need some help here, if you can. Due to the terrain around my house (50 acres in the mountains), I am relocating my VHF antenna and Dish Network dish to a location away from the house that will be completely free of obstructions (trees and ridges) and hopefully will provide the best reception possible. I have surveyed the location, and essentially will be building an antenna farm. My plan is to have a Ham antenna, CB antenna, VHF antenna, Dish Network Sat Dish, and Direct TV Sat Dish located on the site. May even relocate my wireless internet antenna there. The conduit is being put in place now. It is 2″ gray standard issue electrical pvc. The site is about 800′ from the house (through a draw, over a creek, and up a hill).
Quick and dirty, what type of cables will I need to cover that distance for each system? Can I “share” cables between systems (i.e., use one cable for ham and C.B. to be either manually switched or shared via diplexers)? If I run the cables in the same conduit, will there be interference between the systems? Any tips? Thanx.
Surfer – at 06:50
The short answer is that 800 feet is a very long run for any antenna feed line.
The long answer is that the actual loss will depend greatly on the operating frequency and the type of feed line used. Run “ham radio antenna coax db loss” through your favorite search engine and check the charts that are available.
If you prefer a calculator rather than a chart, then see
http://www.timesmicrowave.com/cgi-bin/calculate.pl
Surfer, I was looking at a place where antennas would be a long way from the house. For my satellite internet and cable, I was looking at actually converting the data and video using a computer located at the distant antenna farm onto a gig ethernet data line, and using repeaters or special long haul ethernet drivers (or wireless network with repeaters) to network the local computer to the house network. This approach is getting cheaper as new products hit the market, but is still not simple (and I didn’t do it, gratefully, so I can’t tell you much). But for the different types of signals, coax and wire does have significant limitations so doing everything local to the antennas means you get one cable across. The antenna farm computer can be used with computer digitally tuned ham equipment and “remote-desktop” controlled from your house. Use x10-like software to run the infrared remote control signals over the network to operate your cable boxes, and on and on. So, you need a powered small shed at the antenna farm (you would spend some time there), possible repeater or 2 in the middle of your cable run, overall expensive and not real practical (I only did feature looks - experts in each area of video and ham) would have to tell you if these things actually work), but suitably crazy if you have plenty of money and time on your hands. A company that does smart houses probably would be good to talk to or home automation web info.
Thanx DIC and FD. I’ll check it out.
My suggestion is that you consider constructing a small radio shack at the antenna farm location and run power to it. You will likely get much better performance at lower cost than trying to run large coax that distance. Even the largest coax I am familiar with loses over 1 db per 100′ and an 8 db loss for 800′ is not tolerable. Well made twin lead might do better but that is still a long way to go. A small CMU blockhouse should be relatively cheap……
Many thanks for the recommendation on the ICOM unit. I am thinking ham radio might be a very good way to pull in information near and far in the event of a pandemic smack down. Does anyone know of any group of ham operators who are up to speed on pandemic preps and setting up networks to relay messages, share local observations, etc.??
Dinkers -
I wish I was more knowledgeable about all of this, but I do know that ARES and RACES operate during emergencies. Here is a quote from the link below (from ARRL web page): “ARES is activated before, during and after an emergency. Generally, ARES handles all emergency messages, including those between government emergency management officials. RACES, on the other hand, almost never starts before an emergency and is active only during the emergency and during the immediate aftermath if government emergency management offices need communications support. RACES is normally shut down shortly after the emergency has cleared.”
For an ARRL club search in your area, you can use the following link to find out: http://tinyurl.com/asl92
You can either call ARRL (# will be on their web site) or your local club for information. They will both probably be quite helpful.
LMW and Others
I has told by a DirecTv technician(on-site visit a few weeks ago)that an RG11 cable could easily handle an 800′ distance from the house to a Directv satellite dish. Is he blowing smoke?
Surfer – at 21:00
I’m not trying to be cute … but it depends on what he meant by “easily” and “handle.”
I have no personal experience with RG-11 coax. I have only used RG-8 and RG-58. The first chart I checked showed that regular RG-11 has a loss of 1.35 db per 100 feet (at 27 Mhz). 1.35 x 8 = 10.8 db loss. That means you end up with ~1/10th of the signal at the other end. Will it handle the signal? Yes. If you run 100 watts into the feedline at your house and get 10 watts delivered to the antenna, will you be satisfied with that? I don’t know. If the DirecTV tech made a flat statement that RG-11 would easily handle an 800-foot run, without asking on the frequency being used, the power level you intend to operate at, or any other elements of the equation, is he blowing smoke? Yeah, I think so.
Surfer - I second DIC’s statements, the guy was blowing smoke, and that’s probably because “Larry the Cable Guy” (sorry) doesn’t really understand what happens in cables over distance. As Dennis has been teaching, the longer a run of coax you have, the more signal you lose. But, the signal is NEVER completely gone, so, in one sense, the cable guy is right, RG-8 “can handle” the distance. On the other hand, can the equipment in your living room “handle” the signal that finally crawls along to the cable and reaches it.
Dennis introduced the term dB (decibel). For this discussion, 1 dB represents the ratio of power coming out of a piece of cable versus the power that went in. With a 1 dB loss per foot, that means that you will get about 78% of the power out of a 1 foot run the cable that you put in. dB work in exponential math, so that adding dB means that you multiply the 78 percents. Thus, a 2dB loss represents that you get 78 percent of 78 percent of the power. Thus, while with a 1 dB loss you get 78% of the power out, with 3 dB you only get 1/2 of the power, and with 6 dB you get 1/4 and with 9 dB you get 1/8. A 10 dB loss means you have lost 90% of the power.
Now lets look at the example being discussed above again. Let us assume you are using RG-58 coax, like one can get a Radio Shack. Since we are linking a TV signal back from the DISH, let’s assume we are using channel 3, as things get worse the higher in frequency one goes. The loss of RG-58 at TV channel 3 will be 3.3 dB per 100 feet. Thus, an 800 foot run would incur a loss of 26 dB. Now, since every 10 dB loses us 90%, and we have 20 dB, that is a loss of 99%, multipled by the 6 dB loss which costs us another 75%. Thus, you get 1/4 of 1% of the signal out of the cable that went in.
So, if the DISH put out a signal 400 times stronger than your TV needs, it would work fine after 800 feet. Of course, at close range that would fry the tuner in the TV, so I can guarantee that it doesn’t work that way. So, the cable guy is just blowing smoke. Because he’s never actually tried to run a signal over coax that long.
Now then, there are better coax choices than RG-58. If we used RG-8X instead, its loss is only 2.2 dB per hundred feet at that frequency. In that case, the total loss would be about 18 dB. Following through the calculations, that leaves us with a signal which is about 1–1/4 percent of the original or about 1/75. That’s getting better, as that means we only need to make up 75 times the original power, not the 400 of the RG-58 case.
Continuing up through the realm of Coax cables, as we get to larger, more sophisticated and more expensive cables, we can find better loss numbers. Cable type CNT-240, which is getting to be a thick, heavy expensive piece of cable shows a loss of 1.7 dB per 100 feet at channel 3. This gets us down to a loss of about 13 dB, which would mean that we are now getting 1/20th of our original signal, which is much, much better than RG-58, but still not the best. This coax costs about $0.75 per foot.
At this point, it becomes possible to stick an appropriate amplifier at about the 400 foot point to insure adequate signal reaching the receiver. Such amplifiers are made in in-line cylindrical forms which can be fed power directly through the same coax that it is sending the signal over.
Now, if we get to the realm of specialty microwave cables, one can use Time Microwaves type LMR-400 cable ( at a couple of bucks per foot) and get a loss of about 0.9 dB per 100 feet. This would give us a loss of about 7.2 dB for the run, which means about 1/5 of the original signal makes it through.
Unfortunately, this kind of coax is large enough so that you would only get 3 or 4 runs of it in a single conduit. Also, realize that every connector that is placed into the run will add 1/4 to 1/2 dB of additional loss.
So remoting antennas is a task that requires more than just running longer and longer wires to reach the distant site. An aditional concernt that I have is that such a long run of coax will make you very susceptible to static spike damage from nearby lightning. 800 feet of coax braid makes a dandy antenna for such stuff.
I ap[ologize for not having jumped in earlier, but I haven’t been on FW much for the past few weks due to work issues. But if you would like, we can explore the best ways to get a signal from a remote site to your home. (And if you are seeking to transmit, then it gets more complex. The Radio shack that the guys have recommended becomes more and more necessary).
Eccles, nice to have you back on the wiki! Did not know you are knowledgable in radio, etc., so will ask advice for gear that would make a good base ham radio setup to listen, and to communicate with others in a pandemic. I’m thinking ham operators will be up and running in many places, and can network to spread critical information around. I am hoping to establish a connection with one or more operators in the Bay Area of CA; my daughter is out there, and 3000 miles is a weight on my heart. I am just beginning to work toward a license, but should not have trouble as I have a ham operator friend to push me along. See other comments above. Thanks!
Eccles Thanx for the info. Per above posted advice from Fiddler, DIC, BG, and yourself, I will continue in my efforts to construct an antenna farm.
My objective in the energy / communication aspect of H5N1 crisis is to (1) be energy self-sufficient (combination of grid, hydro, wind, generator) and (2) be able to figger out what is happening “outside” via com systems when all this stuff happens. It will.
Number one is damn near done. Coupla tweaks, and I am set. Number two is still puzzling, however, much of it has been accomplished.
My plan is this - Have: 1. Have regular telephone service, 2. cell phones via different service providers (Cingular and Verizon) in case one or the other goes down at any given time, 3. a sat phone (last resort backup telephone communication source), 4. Ham radio, 5. C.B. radio, 6. T.V. reception via VHF, 7. T.V. reception via both Dish Network and DirectTV, 8. Hand held Scanners that will pick up transmissions from numerous sources, 9. AM/FM radios, 10. internet access via regular telephone line (no dsl or cable access up here), 11. internet access via wireless transmission towers, 12. internet access via satellite. Did I miss anything…besides the ship to shore radio?
My problem is I still have an 800′ run to the antenna farm (over the hill and through the woods), where most of the hard wired items will be located. Yes, I can build a cinder block shack. Yes, I can run 120V power to it. But by building that, how do I get the signals down to the huose - 800′ away?All previous suggestions have been good, but I’m just a Marine. I need a xplenation
Forget the 800 ft coax runs.
It’s unworkable unless you use hardline, and even then it’s not worth the effort or expense.
Look into remote bases for the HF and VHF ham gear. Control them wirelessly.
I run remote bases (including a Uniden digital scanner) on a hilltop at 1800ft above MSL using a version of echolink and a wireless private LAN for the ham gear, and Butel software for the scanner (remote control and audio).
As for internet, you can always run wireless down from the hill to your house using a patch antenna and an amplifier, and a couple of wireless bridges.
I don’t think the Sat TV will do well with that long of a run either, unless you use one heck of a preamp along the way. I haven’t played with sat tv that much.
Better, and cheaper, to build a radio blockhouse on your hill, and go visit it for the heavy duty monitoring.
For emergency communications I suggest the following:
The ICOM rig mentioned a good PACTOR modem Laptop w/ car charger VX7r portable (dual band) w/ software outband mod Dual band Yaesu or Icom mobile w/ outband mod Digital capable remote control public safety scanner Antennas as appropriate for your area.
Services:
Salvation Army’s SATERN HF network for health and welfare traffic
PACTOR (email and BBS over HF)
http://www.airmail2000.com/pprimer.htm
http://www.scs-ptc.com/wm/wm.html
Near Vertical Instance Skywave HF for regional comms of around 100 miles
B.G.
thanx,I guess I almost get it. But, I don’t want to sit in a blockhouse on the hill in order to monitor transmissions. I want all of the stuff delivered to my house.
Where can I get patch antennas and repeaters?
Cisco bridges if you have the $$$
I get a lot of my wireless stuff here: http://www.hyperlinktech.com
We run a mesh network out here in the semi-boonies, with a feed from the “big city” over a long-haul wireless link.
Looks something like this high speed 6 gig down, 1 gig up, DSL line in city….. up to mountain top via 5.8ghz link to one guy’s house…. down to coast on the other side of the mountain with a 5.8gig link to my house, to a 2.4 gig mesh network in the neighborhood.
Also allows us to run our own private IP range on the LAN for stuff like remote cameras, alarm monitoring, sharing huge files, and controlling remote radios and the scanner too.
One of the bored engineers who hit it in the dot com era designed and runs the system. We all contribute $$$ as a coop to keep it running and replace equipment as technology changes. He owns the house on the hill.
Man, that’s a hot setup, Bird! And I bet your dot com friend has excellant power generation ability for backup. At least you will be able to communicate with each other when TSHTF!
B.G. Just now got your last 2 posts. I will add your links to my collection. Thanx. Any idea where I can find someone to design and install a system? Power supply is NOT a problem. I’ve got grid power. If that goes down, I’ve got a 15 kw diesel gen with a 1,000 gal. fully stocked fuel tank, solar array (it’s a biggin - about 2600 watts), and hydro to power my battery bank. I just wan’t to access com. I want a steady source of information when this happens. When it happens, I don’t want to be treated like a mushroom - you know, kept in the dark and fed - uh - bird guano (no offense). Suggestions, any of you knowledgeable folks out there?
Wow. Wasn’t thinking about remote operation but it is allowed by the regs. Cost for remote operation is going to be high, but it can be done. That is way outside my experience and budget, however. <grin> I thought I was being daring by suggesting a remote ham shack!
Thanks, that’s only the partial setup, but the backbone of it.
There are several other outlets in case something goes down. It’s bidirectional.
Backup includes Satellite Internet at obviously reduced speed, and he even runs a VOip pbx with Inmarsat as an automatic failover backup.
So if TSHTF I can still make a phone call, but at $10 a minute.. ouch.
I dare say our outbuilding of a volunteer fire station is probably better equipped for outside ocmmunication in a disaster than the county Ops center.
LOL
LMWatBullRun – at 08:18
Wow. Wasn’t thinking about remote operation but it is allowed by the regs. Cost for remote operation is going to be high, but it can be done. That is way outside my experience and budget, however. <grin> I thought I was being daring by suggesting a remote ham shack!
Actually it doesn’t have to be high at all.
Minimal computer equipment for remote control, and some $50 RoIP interfaces for the audio part are all you need.
Let me dig up some links for my equipment and software and post them in a couple of hours.
Internet Radio Linking Project. Can also be used on a private LAN. Single board Linux computers are cheap.
Scanner over IP information
This is the $50 thingy I use for remote audio , but it looks like they no longer manufacture it.
http://www.ultimatefrs.com/dingotel.html
I use a couple of these along with computer remote control for tuning, etc.
Butel has a single feed license for $50 to remote a Uniden scanner.
B.G. at 12:33
System looks good. It’s affordable, and I will get it. I don’t know nothin about ham/sat com, so I’m goin back to my earlier kwestion: Any ideas where can I find someone that can install all this stuff? Your gouge has been good, but I need someone to install my entire “com system”. I don’t have the time, but I will spend the bucks.
Commercial two way radio shops in your area.
Home automation installers.
Those are my two suggestions.
I have no idea what resources you have in your area.
I would stay away from “Larry the cable guy” however.
You can’t afford my hourly $$ rate or airfare… LOL