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Apptech | 1 Apr 01:07
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Re: [EE]:: Super-Safe, Small & Simple Nuclear Reactor

>> In a cloudy area, mirrors can be used (carefully) to 
>> increase the
>> concentration of sunlight while not exceeding the ratings 
>> on the panels.

> I'm under the impression the limiting factor is 
> temperature rather than
> anything else, IE you could put 4x the sunlight onto your 
> cells with
> mirrors if you water cool them back below around 60C. 
> (which wont use
> that much energy really)

"Concentrator" cells are commonly run at many suns. Cooling 
is a major issue. A coating that stands the energy flux also 
helps.

Standard panel output drops quite noticeably with 
temperature. I found that I could get 10% plus more output 
from a real world panel by running a thin film of cooling 
water over the top surface while operating. Properly 
designed I decided the flow rate could be quite acceptable 
if water was not scarce. Also by "washing a panel to cool it 
down and then watching the output you clearly see the 
change. And it's in all good spec sheets but not noticed by 
many people. Note that performance specs are given at 25C or 
20C and never at 50C :-).

Substantial rear fin / air cooling of a panel may help 
substantially.
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John Gardner | 1 Apr 01:38
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[OT] : ancient astronomy text deciphered

http://www.bris.ac.uk/news/2008/212017945233.html

http://www.bristol.ac.uk/aerospace/research/dynamicsandsystems/kofels/kofelsimpactbook.html

I imagine we'll hear more of this if it's on the up & up.

Jack
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Sean Breheny | 1 Apr 02:28
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Re: [EE] Aviation comms question

No problem with the questions :)

No, I have the blocked version, unfortunately. I paid about $520 USD for it.

Yes, I would recommend it, although I haven't done enough of a
comparison to say it is better than everything in its price range.

It is great for electronics debugging (looking for EMI sources,
checking the frequency of an oscillator and whether it is running,
etc.).

It is also better than any other handheld receiver I've worked with at
rejecting the FM broadcast band in the rest of VHF.

It is even decent in the HF bands. I would say that it is probably the
best handheld wideband receiver out there.

General specs: 150kHz to 3.3GHz coverage (except for cellular if blocked)
True simultaneous dual receive
CW,LSB,USB,AM,FM,WFM modes
Internal loopstick antenna for AM broadcast band (switchable between
this and external antenna)
Bandscope
Nice large display
Something like 1000 memories
Includes Li-Ion battery
CTCSS and other coded squelch decoders (but not trunking)
Built-in 2 hour digital sound recorder
USB computer interface (requires proprietary software)
Decent internal speaker + headphone jack
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Carl Denk | 1 Apr 03:17
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Re: [EE] Aviation comms question

Note that there is simplex communications where the facility, usually 
flight service station (flight plans, weather conditions, and other info 
for safe  flight) transmit on the voice associated with a navigation 
frequency (typically a VOR (VHF omnirange station)) say 113.6 and the 
pilot transmits on a different frequency say 122.1 that has a receiver 
at that ground station.

Vitaliy wrote:
> Sean Breheny wrote:
>   
>> An Icom IC-R20. It can do simultaneous receive of two frequencies. I
>> initially noticed the apparent "duplex" by switching back and forth
>> between the two freqs but then confirmed it using the simultaneous
>> receive.
>>     
>
> Do you have the unblocked version? How much did you pay for it? Would you 
> recommend it? :-)
>
> Sorry for asking so many questions.
>
> Vitaliy 
>
>   
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Cedric Chang | 1 Apr 03:34

Re: [EE] Language choice

How old are you Rich ?   Fru-Fru haas always been a favourite of mine.
Great comment, Doctor S.
cc

> On Mar 31, 2008, at 2:15 PM, Rich wrote:
> What a great write up, Skip.  It is well said and entirely valid,  
> IMHO.  The
> only thing that threw me was "fru-fru."  I don't recall ever  
> hearing that
> term but from the context (hood ornament), which was an excellent  
> analogy, I
> got it.
> TNX
>
> ----- Original Message -----
> From: "Dr Skip" <drskip <at> gmail.com>
> To: "Microcontroller discussion list - Public." <piclist <at> mit.edu>
> Sent: Monday, March 31, 2008 1:42 PM
> Subject: Re: [EE] Language choice
>
>
>> As many an older engineer will testify, form is often an  
>> overlooked part
>> of
>> function. It's a myopic view of the system requirements that  
>> separates the
>> two.
>>
>> If the goal is to have happy customers, or happy users, or sell the
>> maximum
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Cedric Chang | 1 Apr 03:39

Re: [EE]: Quick semi-professional-looking web site generation

NVU is fast to learn, Word is fast, so is Open Office.
Joomla has a definite learning curve.
cc

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Cedric Chang | 1 Apr 03:47

Re: [EE]: Energy guzzlers was:solar hydrogen farm on 10 / 100 square miles

>
>
> Definitely refrigerators - Although this is'nt written in stone
> anywhere. The difference between state of the art & general
> practice in domestic refrigeration is impressive, & energy
> intensive.
>
> Jack

why is that ?
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Richard Seriani, Sr. | 1 Apr 03:53
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[PIC] 16f88; unable to program more than one time

Using external programmer, PIC 16f88 programs without problem the first 
time. After that, programming errors crop up and the device seems to not be 
able to be reprogrammed.

I noticed the user had !MCLR set as I/O and was using the internal 
oscillator. I vaguely recall something reading somewhere about this causing 
the problem. I got a few google hits searching on MCLR and 16f88, but 
looking for more explanation. I haven't been able to find anything on the 
Microchip site.

Thanks for your time.

Richard
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James Newton | 1 Apr 04:03

RE: [EE]Electronic component inventory spreadsheet

Does "snappystuff" allow you to add new attributes to describe your stuff?
For example: If I want to list my socks, and there are currently fields to
put in the size, color, and texture of the socks, but NOT one to put in the
type of material they are made from, could I add that field? Could I tell
snappystuff that socks should also have a field for material?

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James.

-----Original Message-----
From: piclist-bounces <at> mit.edu [mailto:piclist-bounces <at> mit.edu] On Behalf Of
Morgan Allen
Sent: Saturday, March 29, 2008 12:29
To: Microcontroller discussion list - Public.
Subject: Re: [EE]Electronic component inventory spreadsheet

John, hope this is not too shameless a plug, but the website I work for does
almost all of what you are asking. http://www.snappystuff.com acts as
personal inventory management with all sorts of categories, and you can make
your own locations. It is free too.

On Sat, Mar 29, 2008 at 1:05 PM, Carl Denk <cdenk <at> alltel.net> wrote:

> If the issue is importing the text data from the web page or E-mail
> order info, I use a SNAGIT, a screen grabber that can take most anything
> from the screen or clipboard (text or image) and export it to clipboard,
> a file or other output. I use it to copy/paste sort of thing to get text
> (alphanumeric) to the Excel spreadsheet including financial data.
>
> Philip Pemberton wrote:
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James Newton | 1 Apr 04:09

RE: [EE]Electronic component inventory spreadsheet

Nate Duehr Sent: Sunday, March 30, 2008 02:52

>These small proprietary relational databases like Bento seem useful,  
>right up until you have to beat on them to get your data into them in  
>some way that makes sense to you.  Then you just want the simplicity  
>of a spreadsheet or text file again... heh.  I dunno what's the best.   
>I lean heavily back to boring old ASCII text and a reasonably sane  
>directory tree system, most of the time -- but that's my Unix  
>background and profession showing... I can manipulate text... boy can  
>I do that... that's what Unix does best!  But sometimes I yearn for a  
>modern user interface... and then find them annoying... back and  
>forth...

The file system is really a database manager, just like SQL, but optimized
for storing a specific type of data: Files. If you break up files in logical
ways so that they don't get too huge and so that you don't have too many
files in one directory, they work pretty darn well.

Why not put a nice front end on the text files and directories?

Any scripting language or C / C++ can manage that. It just takes some work
to polish it up. 

Or you can use SQL instead and have something that more people will be
interested in helping you with.

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James.

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Gmane