Quote from: cockpitbob on February 26, 2015, 08:34:39 AMAlso, my reading on EMPs also tells me that the damage won't be as bad as many of us think and that the smaller the item (LED flashlight) the more likely it is to survive.

I agree Bob... I am convinced many people have - either deliberately to promote FUD or by misunderstanding the physics - confused an EMP with ionizing radiation from nuclear bursts.  Ionizing radiation can destroy solid state devices but if you and your equipment are close enough for ionizing radiation to be a problem then loss of your equipment pales into insignificance compared to radiation sickness or the loss of your life.  However, EMP is not ionizing radiation and does not pose the same risk to life or equipment.

Testing has shown repeatedly that if most consumer electronic devices are not connected to longer wires (such as antennas, power cords, headset wires, etc) they will be unaffected by an EMP.  That's where the old standard of disconnecting everything from your radio and putting it into a Faraday cage comes from.  Tests conducted on modern automobiles have shown the worst that will happen is the engine will stall, but would restart immediately.

The consumer equipment at risk is that which is connected to external wiring, such as  the power grid, telephone lines, cable TV, and the like.  The damage there is caused by very high voltage induced on long wires, since an EMP is a radio wave (EMP = Electro Magnetic Pulse) and radio waves induce voltages on antennas.

The main risk to preppers is from damage to the grid.  Depending on the location and size of an EMP event commercial power and communications could go away for an undetermined length of time and that will be a Very Bad Thing.

Wally

QuoteThe PSDR2 can modulate signals, but it can't filter or amplify them. In short, it can't transmit by itself.

Since this seems to be an exciter, what are you guys planning to use for an output stage?

Wally

Edit - board seems to be acting up... it only posted half of my post, cutting it off in the middle.

I believe most sterilization of that nature is done by very high radiation levels.  Apparently that is how bandages and medical equipment are sterilized after packaging.

Wally

Quote from: vwflyer on November 07, 2014, 02:03:09 PMYa'll pushed me over the edge to get into CW, QRP, and kitting

Dang, I need to get my glasses checked.  There for a minute I thought you said knitting, and I thought Ray had done a good job of keeping that part under wraps.  So to speak.

Wally

Quote from: Jim Boswell on October 29, 2014, 11:29:51 AMmake a 2meter J-pole using 300 ohn twinlead and house it in 1/2 gray PVC pipe.

I did that some years ago and had a lot of trouble getting a good SWR on the antenna.  I chose gray electrical conduit because it would be harder to see against the sky than white water pipe.  Unfortunately, I failed to take into consideration that the gray color in my electrical conduit had come from carbon additives - so it detuned the antenna.  By the time I figured that out, I had finally gotten a reasonable match but it took a lot of trial and error with the antenna analyzer to get it - measure SWR, take the antenna out of the conduit, trim, reinstall in conduit, measure SWR, remove from conduit, trim, reinstall in conduit... ad nauseum.  I could have saved a lot of time and frustration if I had used white water pipe and painted it.

I don't know if all gray PVC pipe contains carbon, but I would choose something different if I did it again.  If there's enough in there to detune the antenna then there is enough to absorb some of the power.

Wally

Nice job, it looks great.

Wally

Quote from: cockpitbob on October 22, 2014, 09:03:12 AMAnyone know the shelf life of those vacuum packed bricks?

You might consider roasting your own.  I have been doing this for a few years now, and it's hard to go back to store bought coffee.  "They" used to say frozen green (unroasted) beans last forever, but now some experts are saying that isn't really true.  Some people say that degradation sets in but I don't know if it is quantifiable.  Plus, they are usually talking about high end coffee, not campfire swill like we would be grateful for in a nasty situation.

I buy fresh from Sweet Maria's at http://www.sweetmarias.com
but MREDepot has canned green beans they claim has a long shelf life:
http://www.mredepot.com/servlet/the-881/coffee-beans/Detail

My roasting (a medium roast) results in a bean weight loss of about 13%, so MRE Depot's 19 ounce can of green beans should yield about 1 pound of roasted beans unless you go to a very dark roast... so about $12 per pound of finished product, which doesn't strike me as too bad.  Although, I don't know how good their beans are.  He is currently selling a Central American bean but the case I have put away is from Brazil, I think.  But the Central/South American coffees are generally in line with my tastes.

Why, no, I'm not a coffee snob... why do you ask?

Wally

Gil, I thought this might be of interest to you because of where the hosting service for this forum is located.  A week or so ago there was an article on Brian Krebs' blog about inconsistencies in court documents filed in the Silk Road drug bazaar case.  The FBI claimed it identified the server location because of a Captcha screen leaking the true IP of the server, bypassing the Tor hidden services the main site used.  Lawyers for the Silk Road defendant, as well as some security experts, threw the BS flag on that claim.  Krebs explained the background in this post:
http://krebsonsecurity.com/2014/10/silk-road-lawyers-poke-holes-in-fbis-story/

Today the Naked Security blog from Sophos had information on the government's response to the legal challenge.  Among other things, they said:

QuoteThe server was located offshore in a data center in Reykjavik, Iceland. Once the FBI figured out its location, it was Reykjavik police who accessed and secretly copied the data on it.

There is a lot more, but the bottom line is the Feds are claiming 4th Amendment protections don't apply for several reasons - including the server being located in Iceland, so the lack of a search warrant didn't matter.

Here's the full article:
https://nakedsecurity.sophos.com/2014/10/10/fbis-warrantless-hack-of-silk-road-was-legal-prosecutors-claim/

Of course, the Silk Road was an extremely high value target for prosecution, but I thought the logic behind the FBI's thinking might be of interest to people interested in security topics.

Wally

It's a convenient way to send simple data like weather data.  If you have the proper sensors and data interface it can be used for monitoring things like voltages, temperatures and, of course, position.  Our ACS group uses it to monitor river levels in an area subject to flooding.  Other people have used APRS to track progress in bike races or marathons (how soon will they get to a checkpoint?), track SAR dogs, etc.

The format of the data stream is predictable and is easy to parse to extract the data.  Free software is available to receive the data and it isn't hard to write scripts to upload results to a web server.  Or, the data can be pulled from sources like aprs.fi using their interface.  You don't have to include GPS information; it can be set up with static coordinates that you enter.

I think it is worthwhile getting familiar with it just to understand what it is and how it works.  You can take a look at http://aprs.fi to see what's out there.  Search on your zip code and you'll see what people in your area are beaconing.

Wally

Ranger, you might consider what bands and modes you plan on using on the radio.  I don't have and have never used an 817, but I have heard that one of the reasons they are commonly available used is because people buy them for the reasons you stated and then find out 5 watts SSB doesn't work all that well.  If you plan on working CW (Morse Code) then there is no problem working the world with 5 watts, but SSB isn't nearly as effective reaching out to someone.  Many less experienced users find it difficult to make contacts using low power SSB.

Before buying any rig, evaluate how well it fits the specific way you plan to use it - CW, SSB and 2m FM all have very different characteristics.

Wally

The reason for considering alternatives is to think through the process rather than making assumptions.  Solar is not a viable option for me (and many other people) because of climate and shading from many trees - but I have access to lots of wood.  Showing lights at night is not much of a concern for me since I can't normally see my neighbor's lights anyway (nor can they see mine) - I don't live in suburbia.  My well pump wants 240 volt power and it would be handy to be able to use it.  I have a large water storage tank that would allow me to go several days between fill cycles.  If I have renewable power to charge batteries maybe I can cut a deal with a neighbor to get eggs in return for charging their batteries - that is more likely to be the scenario in my neighborhood than hordes of zombies looting and pillaging.  I am not physically able to farm, but I may be able to do other things in exchange for what other people produce.  My old blacksmith tools might come in handy in that situation.  Isn't that the way life worked before the Industrial Age?

I am not assuming we will go from everyday normal to TEOTWAWKI overnight - I am assuming there are a multitude of scenarios that can range from power outages of a few minutes to a year or so and then on up to forever.  In my opinion, each situation calls for a different solution, or range of solutions, and I don't see any point in taking cards off the table without at least looking at them.

I believe Options Are A Good Thing (tm) but that requires exploring options, even if ultimately they sink farther down the priority list or drop completely off the list.

I'm familiar with life in Florida without air conditioning - Florida is my home state and I'm old enough that very few homes were air conditioned when I was young.  I was in my third year of college when I moved into an air conditioned apartment in Gainesville and decided that was an improvement over living without it.

Wally

I looked at the possibility of steam power a few years ago and sort of backed away from it.  I didn't look at efficiency, but the main disadvantage of steam is that it involves high pressures and high temperatures.  The penalty for a mechanical failure can be severe - as in serious injury.  Of course, people do it all the time and utube is filled with home made systems, but I started thinking that a commercial system might be preferable to homebrew stuff.  But then you get into some serious money; a 5 hp steam boiler and matching steam engine coupled to a generator will set you back a fair amount of cash.  Most of the hobby steam systems are propane fired because propane is easy to regulate - wood isn't so easy.  You could convert a gasoline genset to propane and store an awful lot of propane for what you would have in the steam system.

There are no good answers; all of these alternative systems have major drawbacks of one sort or another.  A lot depends on what your goals are and what level of mechanized living would be required if the grid went away.  I realize many people live off the grid today, but most seem to do it where there is abundant solar energy.

Edit to add:  Luigi, when I was looking into steam it appears that most commercial stuff available today is hobby oriented.  There are small steam boilers and engines available for small steam launches, which appear to be popular in the Puget Sound area.  Coupling a generator head to a steam engine would probably end up being a home project even if you used a small commercial boiler and engine.  Here's a guy who builds steam stuff, but it isn't cheap:

http://www.ebay.com/itm/Steam-Speeder-Locomotive-Railroad-Engine-Boiler-with-Pump-whistle-gauge-oiler-/261496830131?pt=LH_DefaultDomain_0&hash=item3ce26cf8b3

Wally

There are some good links in a thread just below this one, "Brand new to radio":
http://radiopreppers.com/index.php/topic,813.0.html

Reading through that thread may refresh your memory on some things.

Welcome to the forum.
Wally

Quote from: mdmc on June 20, 2014, 10:51:17 PMWhen summer is over, I plan to start on a wood gasifier.  Can cook with the flame or run a generator with one. We loose power for extended amounts of time here, generally in the winter.

I thought about doing that for backup power because we have plenty of wood but not enough sunlight for practical solar.  Several year ago I bought a book titled "Convert Wood Into Charcoal and Electricity" by Richard M. Buxton, published by Lindsay Publications.  Lindsay retired and is no longer in business, but copies of the book are still available from "Your Old Time Bookstore", who appear to have bought Lindsay's remaining stock.
http://www.youroldtimebookstore.com/product-p/22873.htm

He gives detailed descriptions of his experiments in making producer gas and using it to power a Briggs & Stratton engine driving a car alternator, including how to modify the engine.  The biggest problem he ran into is the gunk that's present in the gas - he ran his gas through three cleaning stages and still has to pull the head off the engine to clean the tar off valve stems after every run.  Otherwise the tar solidifies and the valve stems seize in the guides.  He says there are some nasty by-products coming out of the kiln that bear some thinking about.  I would suggest picking up a copy of the book; it's fairly cheap ($9.95 plus shipping) and has some some good details.

Wally

Quote from: RadioRay on June 17, 2014, 01:23:21 PMThe BEST, that I recommend is my favorite becuase it's designed for just-in-case and so it strong of WHY things work: Emergency Navigation.

http://www.amazon.com/Emergency-Navigation-Improvised-No-Instrument-Methods/dp/0071481842/ref=sr_1_1?ie=UTF8&qid=1403025653&sr=8-1&keywords=Emergency+Navigation

I have that book... maybe I should take it off the shelf and actually read it.  I think I bought it when I bought the 50 year almanac.

Wally