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Author Topic: Building Emergency Communication Station  (Read 7820 times)
WQ6M
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Posts: 7




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« on: June 20, 2011, 08:51:44 PM »

Hi:

I am a newly minted Amateur Extra, looking to set up shop.
I have a mobile Kenwood TH-D72 (only equipment so far).
My plan is to set up a portable Communication Station.

I am looking at a Buddipole Antenna system.
I have camping gear.
For the station I have looked at either the Yaesu FT-897D or the ICOM IC-7000.
I need to consider my options for power. Power will need to be a battery system with a small generator?
My truck has a 400W 120v inverter outlet which I have not yet used.
Other gear I have not considered?

Still pondering the details.
Planning to visit some clubs at Field Day this weekend.
Ideas?

Tim
WQ6M
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K1CJS
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Posts: 5981




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« Reply #1 on: June 21, 2011, 08:35:03 AM »

Station?  Or Rig?  A station may be many radios or a couple, but it would require more in the way of antennas, cabling and power needs than you may want to haul around.  In any event, google 'go kits' and 'portable ham emergency radios' to see what others are doing.  There are also a lot of references on this site and on the ARRL site for the same purpose.

If I were you, I may want a simple 2 meter FM radio and a small HF rig only.  You're probably not going to want to--or have the time to--use much else.

Oh, and BTW, if you look at the owners manual for your truck, you're likely to find that it recommends not using the AC outlet for anything too much or too long--unless you have the engine running.  Much better that you run everything off 12 VDC.  That way, you won't have the need to convert and reconvert power sources.  

A 12 volt deep cycle battery can be your operating power source, and you can make up a charging harness from 10 gauge wire so you can recharge it from your truck alternator.
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W8JX
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Posts: 5594




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« Reply #2 on: June 21, 2011, 10:18:57 AM »

I would use a combo of generator and batteries. You can buy commercial golf cart 6v deep cycle batteries and they are very rugged and not expensive. They are generally rated at sustaining a 25 amp load for close to 5 hours. 6 of them in series/parallel for 12v would provide a very good reserve and hold a 25 amp load for well over 15 hours. (as drain per battery decreases, efficiency increases) You could power a inverter too for lighting but do use modern high efficiency light blubs or LED ones and do not waste inverter/battery power on old style bulbs. The generator should be at least a few KW so that it can not only provide backup power but also rapid charge battery bank when needed.
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ONAIR
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Posts: 1738




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« Reply #3 on: August 30, 2011, 09:00:03 PM »

Hi:

I am a newly minted Amateur Extra, looking to set up shop.
I have a mobile Kenwood TH-D72 (only equipment so far).
My plan is to set up a portable Communication Station.

I am looking at a Buddipole Antenna system.
I have camping gear.
For the station I have looked at either the Yaesu FT-897D or the ICOM IC-7000.
I need to consider my options for power. Power will need to be a battery system with a small generator?
My truck has a 400W 120v inverter outlet which I have not yet used.
Other gear I have not considered?

Still pondering the details.
Planning to visit some clubs at Field Day this weekend.
Ideas?

Tim
WQ6M
    Don't forget to have an 11 meter SSB AM rig on hand.  In the event of a serious emergency, it will give you a link to the truckers and to many non hams.
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K9KJM
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Posts: 2416




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« Reply #4 on: August 31, 2011, 12:22:57 AM »

I agree that 12 volts operation is the way to go with a mobil operation.  Pretty much forget the 120 volt AC.......
The idea to add a deep cycle battery is good.   A single 12 volt marine type deep cycle battery will work well.  If you need more capacity, The idea to use several 6 volt golf cart type deep cycle batteries is a good one.
Also check out solar panels to help keep the battery charged.   The Harbor Freight Tools 45 watt panel that sells for 149 bucks with the coupon from many magazines is a pretty fair deal.
http://www.harborfreight.com/45-watt-solar-panel-kit-90599.html?hft_adv=10062&gclid=CKLN5MP_-KoCFSUEQAod4FNiGA
(The ad shows 199 dollars.  Check magazines for the 149 dollar coupon.)
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W6RMK
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Posts: 650




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« Reply #5 on: August 31, 2011, 06:41:35 AM »

Rather than golf cart/marine batteries, both of which spill easily...
Get yourself a big AGM/VRLA sealed battery (aka "gelcell", except nobody makes them gelled any more).  They are safe to have in the passenger compartment or trunk, for instance. (actually, most batteries are ok in the passenger compartment, except for the acid spill issue)

Seriously consider one of the voltage boosters (from MFJ, for instance), because if you run a 100W rig (like the IC7000) off a battery, the voltage will sag, and you lose your output power.  You can also use that to make up for voltage drop if you have to have the battery (which is heavy) some distance away from the rig (which is light), or if you're improvising your 12V power source

You need an autotuner.  Sure, you could adjust your antenna each time you use it, but an autotuner, in a emergency situation, means you can throw up pretty much any random piece of wire, and it will work.  I put the "caseless" SGC-239 tuner in an inexpensive cable TV service drop box, so I can put the tuner at the antenna, and then run 50-100 ft of coax from rig to tuner. (2 25', 1 50' length, and barrel connectors, and a roll of tape).  Tuner at antenna means no coax mismatch loss.

Get yourself a half dozen or so 2.4" diameter 31 mix ferrite cores.  They're really handy for suppressing RFI, for choking feedlines, power cables, etc.

Then, it's all a matter of operating...
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N3YZ
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Posts: 49


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« Reply #6 on: September 09, 2011, 07:58:22 AM »

Good idea, Tim.

You certainly have options. Several have and will be presented. However may I add some comments, since you noted the FT-897D.

An FT-817 or other QRP rig, coupled with a 7-12AH AGM/gel cell (Battery Warehouse) and a good high HF dipole will certainly meet any minimum emergency comm needs. The FT-817 draws .4A on RX. I recently used that combination during our 5 day Irene power outages. Investigate PowerPoles for your 12V connections. Went well. For effectiveness, I even worked QRP DX into A6 on 20M SSB.

An FT-897D with batteries is ok. Frankly, I haven't added batteries to mine, since the two 4AH batts limit you to 20W. They drain fast. The FT-897 draws about 1A on RX. For battery ops, connect to that aforementioned gel cell.

Also, you might investigate solar generation. The CT Solar site, http://www.ctsolar.com/solarpowerforamateurradiofaq.aspx, might be useful.

73! John, Annapolis, MD
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KF4UVG
Member

Posts: 28




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« Reply #7 on: September 24, 2011, 07:18:35 AM »

I have the ft897D and the buddipole system and enjoy using them camping. If you are driving all your gear in and not backpacking 897 and deep cycle battery works great. One suggestion on the buddipole, I just bought the versatee and then the two long wire adapters and coax connection. it is a very fast dipole system to set up. I throw the versa tee on a 16' pole and the wire legs unwind to 20, 40 or 80m. There is a 1500' peak that I set up on with a steep drop off and this systems seems to be ideal for those situations. The only change I would make if I had to buy it all over again is that I bought the z11 tuner and it works great but I would get the one that LDG makes to mount to the 897 just so it would attach to the rig,but you can get the buddipole close without a tuner and add that later. I have not used the 7000 so I couldn't give you feedback on that one. (also if you have an ipad,ipod,iphone several apps for radio that makes camping/radio easier)

Good Luck
K4HSI
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AA4PB
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Posts: 12770




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« Reply #8 on: September 24, 2011, 10:21:15 AM »

You may want to look into a Honda Eu1000i or Eu2000i generator/inverter unit. They'll power a 100W transceiver and a few accessories, lights, etc.

The first question you need to decide is how "portable" does the station need to be and how long does it need to be on the air? If you are going to "backpack" it to the site then you probably need to consider QRP (5W), small batteries, and perhaps a solar based charger. If you are going to be able to drive to the site then a 100W radio and generator is probably a better solution.

The BuddiPole is a good antenna, but full sized wire dipoles are much more efficient, especially on the lower bands, if your site has trees or something you can use for supports. If your station is primarily for HF emergency use then 75M is probably where you will be operating and a BuddiPole is pretty inefficient on that band. On the other hand, if your primary goal is working distant stations and having fun then 15M or 20M will likely be the best bands and the BuddiPole does pretty well on those bands.

The inverter in your truck is probably not a good solution. The loss in the inverter plus the loss in the AC power supply needed to get 12VDC for the radio is inefficient as compared to just powering the radio directly from a battery. In addition, an automotive type battery is not intended to provide continuous power and be deeply discharged and recharged numerous times. A SLA or glassmat type will survive that type of usage much better.
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AA4HA
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Posts: 1386




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« Reply #9 on: September 26, 2011, 06:39:11 AM »

I would try to keep everything as DC as possible. If you start with a battery then you can always consider things like charger circuits for alternative energy sources (solar, hand crank generator, wind, etc...). You want to provide yourself with some form of lighting (LED lighting works great). Otherwise you are back in the days that when the sun goes down you do one of two things... sleep.. or well, something that can lead to sleep for at least one partner <j/k>.

It also depends upon what type of emergency are you planning for. How long will you be without the ability to charge a battery from a vehicle? How long of time before you can see commercial AC power. Do you expect this equipment to endure any extremes of performance (cold weather, waterproof, back-packable, EMP?).

I use a Yaesu multi-band HT for VHF/UHF and a PRC-174 for HT. In a spot I can always drag out the old Yaesu FT-100d for higher power vHF/UHF or SSB/CW ops in HF/VHF/UHF.

I had to come up with a less than conventional charger circuit for the PRC-174 as it wants to see 24-28 VDC and to charge it with a 12 volt supply required a simple switch arrangement so I could charge one half of the battery at a time.

The downside of things like the PRC is that they are heavier than portables or even mobile radios.
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Ms. Tisha Hayes, AA4HA
Lookout Mountain, Alabama
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