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ZL3AI > APRDIG 15.12.06 22:30l 219 Lines 9077 Bytes #999 (0) @ WW
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Subj: [APRSSIG] Vol 30 #12, 1/1
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From: ZL3AI@ZL2BAU.#79.NZL.OC
To : APRDIG@WW
Today's Topics:
1. Re: Wiki pollution (Tom Russo)
2. RE: Wiki pollution (Scott Miller)
3. RE: backup pwr systems (Alex Carver)
4. RE: backup pwr systems (Robert Kirk)
5. TGR2SHP TIGER/Line translator is now Freeware (Ian Millett)
----------------------------------------------------------------------
Message: 1
Date: Tue, 12 Dec 2006 11:13:36 -0700
From: Tom Russo <russo_at_bogodyn.org>
Subject: Re: [aprssig] Wiki pollution
[This is a response to a really old posting, because it's once again
becoming a problem]
I just referred a bunch of local folks to the wiki at info.aprs.net as a
one-stop-shop for information and links to information about APRS. At the
moment it's in a bit of a sad state.
On Fri, Jun 23, 2006 at 04:12:59PM -0700, we recorded a bogon-computron
collision of the <scott_at_opentrac.org> flavor, containing:
>I just killed several hundred comments. I started with a couple dozen spam
>keywords, and finally just deleted anything with http: in it. I'm going to
>set up a script to do cleanup periodically (at least daily) and see if I can
>lock it down more.
Once again, the info.aprs.net Wiki's comment section has been filling up
with spam. Some of it is pretty nasty. A quick scan of the
"RecentlyCommented" page shows no legitimate comments in two months, and a
couple of pages of spam in that time.
Also, it seems that some folks are using the comment form to correct or add
information to Wiki pages instead of just editing the page. The whole
value of a wiki is if the community keeps it correct and honest by editing
pages directly, and anonymous comments aren't nearly as useful as page
corrections --- especially when the comments are almost completely obscured
by a steady influx of links to gambling sites and other sites of
questionable value.
Perhaps the comment feature serves no real purpose --- if it were
unavailable, it couldn't be spammed, and legitimate contributors could be
encouraged to use the actual wiki-editing features instead.
>>-----Original Message-----
>>From: aprssig-bounces_at_lists.tapr.org
>>[mailto:aprssig-bounces_at_lists.tapr.org] On Behalf Of
>>scott_at_opentrac.org
>>Sent: Friday, June 23, 2006 3:45 PM
>>To: russo_at_bogodyn.org; 'TAPR APRS Mailing List'
>>Subject: RE: [aprssig] Wiki pollution
>>
>>>Does the software runing the wiki allow for commentary to be restricted to
>>>registered users? Is there anyone who can clean out the dozens of pages
>>>of junk to make it more usable for the intended audience?
>>
>>Not that I can figure out. If anyone knows more about the software, let me
>>know. I've cleaned out a bunch of spam, but I haven't checked in a while.
>>If it's all coming from specific IP addresses, I can block them.
>>
>>Scott
>>N1VG
--
Tom Russo KM5VY SAR502 DM64ux http://www.swcp.com/~russo/
Tijeras, NM QRPL#1592 K2#398 SOC#236 AHTB#1 http://kevan.org/brain.cgi?DDTNM
"And, isn't sanity really just a one-trick pony anyway? I mean all you get is
one trick, rational thinking, but when you're good and crazy, oooh, oooh,
oooh, the sky is the limit!" --- The Tick
------------------------------
Message: 2
Date: Tue, 12 Dec 2006 11:22:49 -0800
From: "Scott Miller" <scott_at_opentrac.org>
Subject: RE: [aprssig] Wiki pollution
Agreed. I just set the comments to hidden by default - we'll see what this
does.
Scott
N1VG
------------------------------
Message: 3
Date: Tue, 12 Dec 2006 13:04:16 -0800 (PST)
From: Alex Carver <agcme2002_at_yahoo.com>
Subject: RE: [aprssig] backup pwr systems
>No, you didnt read my post correctly. I said a
>synchronous inverter which means it cannot generate
>power on its own with out the presence of the 60 Hz
>grid in the first place.
>It is inherently safe by design.
>
>Bob
I did read the original post. A lamp dimmer does not inject power back
into the grid. It controls power to the load. The harmonics from a lamp
dimmer are horrendous but they show up at the lamp, not the meter. It
doesn't matter which way power is flowing. Harmonics will flow as well.
Your incoming power is free of harmonics but your inverter (if poorly
designed) would be generating harmonics which then DO flow out of the house
(verified this with an actual power engineer, this is a constant problem
with industrial loads). The harmonics are also attenuated because the
dimmer does not generate any energy through an outside source, it just
takes energy and modifies it. The power grid is a low frequency RF
transmission line system as much as it is a power system. The DC or AC
resistive load of the system has nothing to do with the RF harmonics
generated, just the RF impedance of the system. Think about it that way
because the power engineers do (they are constantly worried about the
impedance of the grid, not the DC or AC resistive load). Harmonics
generated by an amplifier in one of our radios will show up everywhere down
stream. Same thing happens on the grid if a poor quality inverter is tied
directly to it. An inverter generates energy from the battery to the
output terminals. At 400 watts, your harmonics are not exactly low energy
any longer.
Grid-tie inverters are expensive because they use inverter designs that
produce very minimal harmonics that would get injected into the grid. The
K-Mart blue light special inverter that most of us can afford easily for
our computers is called a Modified Sinewave inverter. It's made of a stack
of two or three square waves and has tons of harmonics. But, the harmonics
are on the OUTPUT of the inverter which is only plugged into the load.
But, for your design, the grid is the load therefore the harmonics wind up
in the grid.
Your "synchronous inverter" is exactly a grid-tie inverter. We're not
calling it a grid-tie just for fun, that's actually the name for it. It
synchronizes itself constantly with the grid to ensure that there are no
phase imbalances. If you have a phase imbalance, you run the risk of
floating the neutral or ground wires which would also be a major safety
concern. Turning this into a plug-in device instead of having a qualified
person install it will do more harm than good. That's why they're designed
to be installed instead of plugged in.
Your $100 inverter solution really boils down to a standard UPS with all
the devices wired into it with a handful of extension cords. You won't get
what you want (a plug-in grid-tie) for cheap and not cause problems
somewhere. You can't have this one both ways. It's either cheap and
you'll have to rewire stuff, or it's expensive but done properly such that
you don't disturb the grid.
....Or you just drop off the grid completely. A bit extreme but that's
your third option.
KF4LVZ
------------------------------
Message: 4
Date: Tue, 12 Dec 2006 22:19:48 -0500
From: Robert Kirk <isobar_at_bcpl.net>
Subject: RE: [aprssig] backup pwr systems
At 04:04 PM 12/12/2006, Alex Carver wrote:
>[...]
>...Or you just drop off the grid completely. A bit
>extreme but that's your third option.
That's a pretty good solution. All you have to do is spend $34,000 and
reduce your average house load to 1 amp.
See an article in the new Popular Mechanics which shows how yo do it.
http://www.popularmechanics.com/technology/energy_digital/4204459.html
Bob Kirk
N3OZB
------------------------------
Message: 5
Date: Tue, 12 Dec 2006 23:47:12 -0500
From: "Ian Millett" <n3cva_at_verizon.net>
Subject: [aprssig] TGR2SHP TIGER/Line translator is now Freeware
>From the GIS Tools website www.gistools.com
GIS Tools Software is Now Freeware
GIS Tools, providers of software such as TGR2SHP, TGR2MIF, and Census
Summary File translators will now make their software available as
freeware. Dr. Bruce Ralston, the author of these programs, states that
making these programs available for free is part of his service on the
Association of American Geographers Census Committee. In addition to making
the executables available, the source code for TGR2SHP is also available
along with a technical whitepaper describing the logic and structure of
TGR2SHP. States Ralston, "In working with students, and in my own
self-education, I have found some of the ideas used in TGR2SHP,
particularly efficient extracting of the topology in TIGER and the strategy
for quickly assembling area features (polygons to us older folks), to be
quite instructive. Students who have been exposed to these ideas seem to
have a better understanding of how programs can be structured to exploit
topological relationships." The programs, user manuals, whitepaper, and
source code can be found at http://tnatlas.geog.utk.edu/downloadfree.htm. A
whitepaper and source code for the summary file extractors will be released
before the end of this calendar year.
note: Thanks to Dr. Ralston for releasing his software and source code to
freeware.
Ian, N3CVA
Geographer
------------------------------
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