xmit power of phone hotspot

Is this part of your request for an RF jammer?

A Raspberry Pi 3B requires 5V at about 0.5A = 2.5 watts. If you add a cell phone transmitter of some sorts, the power and associated range will be controlled by the cell site so that it uses the least amount of power needed to maintain a minimal BER (bit error rate). My guess would be 5V at 0.7A = 3.5 watts for the typical wi-fi cellular hotspot. So, you'll need a continuous 6 watts of power for your bomb server err... very hot spot.

There are plenty of portable charging devices with 5V USB ports. For all day (24 hrs), you'll need: 6 watts * 24 hrs = 144 watt-hrs Assuming you run from 12V batteries, that's a: 144 / 12 = 12 amp-hr battery. There are conversion and charge inefficiencies involved, so I would increase this to 16 amp-hr. Since the battery will probably not be used after the IED jam session, you don't need to worry about depth of discharge. However, if you plan to use it again after the initial failure, you should not discharge the battery past about 50% SoC (state of charge) or 32 amp-hrs. Look for something with either a

12V 32 amp-hr gel cell battery or the equivalent in LiIon.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

No, I'm not that whacko. I want to run a portable website from my phone where there is no wifi but the parents of the students I'm teaching all have smartphones/tablets and nothing to do.

I just did a bit of a test and the phone I'm using (Sony Xperia C2004) almost has about 1/4 of the range and I'd like, and after four hours it said it had 35% battery left.

I'd like to be able to run this off one device; external battery if required but I'd rather just have the phone do it all.

Another requirement is that the phone be rootable so the webserver will use port 80 - unrooted it's stuck with 8080.

So:

good hotspot xmit power/range good battery rootable cheap (but you probably knew that already)

There are plenty of portable hot spots on the market. The problem is that they require activation by the cellular vendor who usually wants a 1 or 2 year contract. You can buy them outright, but there's expensive. For example: $200 to buy (or $50 with 2 year contract). 22 hr battery life. It has a USB 3.0 hard disk connector, so I would guess(tm) is can do NAS server and might have a built in web server. I can't tell from the useless specs.

More of the same:

Give me a break. 1/4th of what distance in feet, meters, cubits, or whatever? I can dig out the wi-fi transmit power of any portable hot spot from the FCC ID data. Without looking, my guess(tm) is 20 mw or less. Such devices generally are used in an automobile, bus, or office, where wi-fi range is not as important as battery life. Some boxes have external antenna connectors, which might be worth using.

Check with your unspecified cellular service provider for what they charge for tethering.

I can probably find something for the first 3, but not cheap. I suggest you look into portable hot spots. The 3G portable hot spots are on their way out to be replaced by 4G. I have a box full (somewhere). They're not very fast, and don't work on newer 4G only cell sites, but they are cheap.

You might get a better answer on Howard Forums:

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

This might help: "How far does a mobile phone WiFi hotspot reach?"

-- Jeff Liebermann snipped-for-privacy@cruzio.com

150 Felker St #D Santa Cruz CA 95060 Skype: JeffLiebermann AE6KS 831-336-2558

[big snip]

I think you don't understand.

I don't want to provide internet.

I want to provide a single website that is on my phone they can get to.

What I have works NOW, except that I would like longer range.

We have built and installed WiFi hotspots in an Asian country that provide clear reception of WiFi signals for a radius of 2 kilomters in urban areas.

Wouldn't a Mifi up on a pole do pretty much what you want out of the box

- you just need a bigger battery to keep it going.

--
Regards, 
Martin Brown