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201. Re: [TenTec] New Omni VII (score: 1)
Author: "Gary Hoffman" <ghoffman@spacetech.com>
Date: Sun, 4 Mar 2007 20:07:52 -0500
Carl, How about the Ethernet connection ? Functional ? Powerful ? Useful for remote operation and stuff ? Can I listen in the house on my pc, while the radio runs up in the shack ? 73 de Gary, AA2IZ
/archives//html/TenTec/2007-03/msg00056.html (9,938 bytes)

202. Re: [TenTec] emergency back up power (score: 1)
Author: "Gary Hoffman" <ghoffman@spacetech.com>
Date: Mon, 5 Mar 2007 00:20:42 -0500
Paul, My array of batteries can provide about 1500 amp hours, provided that the discharge rate is kept reasonable. No discount sources that I know of. That's because most batteries that have seen use
/archives//html/TenTec/2007-03/msg00060.html (10,553 bytes)

203. Re: [TenTec] emergency back up power (score: 1)
Author: "Gary Hoffman" <ghoffman@spacetech.com>
Date: Mon, 5 Mar 2007 17:19:43 -0500
You will find "good" used batteries sometimes, in some places. If you do, they can save money. If they turn out not to be so good, they will be a total waste of money. Your mileage will vary. I belie
/archives//html/TenTec/2007-03/msg00074.html (14,724 bytes)

204. Re: [TenTec] emergency back up power (score: 1)
Author: "Gary Hoffman" <ghoffman@spacetech.com>
Date: Mon, 5 Mar 2007 17:21:51 -0500
I'll bet that the battery voltage, as delivered to the actual radio, is a little low. Going to a sine converter and 115 VAC power fixes this issue totally. Gary will even Paragon to voltage the optio
/archives//html/TenTec/2007-03/msg00075.html (16,276 bytes)

205. Re: [TenTec] emergency back up power (score: 1)
Author: "Gary Hoffman" <ghoffman@spacetech.com>
Date: Mon, 5 Mar 2007 22:24:04 -0500
Modern sine wave inverters of the sort sold for solar power systems are far above 90% efficient. I don't know about the linear power supply specifically used by Ten Tec, but I have never seen any pro
/archives//html/TenTec/2007-03/msg00090.html (11,350 bytes)

206. Re: [TenTec] 12 Volt boost ckts (score: 1)
Author: "Gary Hoffman" <ghoffman@spacetech.com>
Date: Mon, 5 Mar 2007 22:28:24 -0500
That's fine, as long as all you want is 12 volts. As I explained in my first post, my goal was to power all kinds of stuff, lights and things, from my emergency supply. A 12 volt DC booster does not
/archives//html/TenTec/2007-03/msg00091.html (8,820 bytes)

207. Re: [TenTec] emergency back up power (score: 1)
Author: "Gary Hoffman" <ghoffman@spacetech.com>
Date: Mon, 5 Mar 2007 22:34:26 -0500
Well you've been lucky on the batteries. Congrats ! :) Stepped sine inverters are to be avoided at all costs, but in the renewable energy world they have all but become obsolete. You have to go out o
/archives//html/TenTec/2007-03/msg00092.html (19,274 bytes)

208. Re: [TenTec] emergency back up power (score: 1)
Author: "Gary Hoffman" <ghoffman@spacetech.com>
Date: Mon, 5 Mar 2007 22:42:26 -0500
The alternative to big wires is to operate at high voltage DC. Hook the batteries up in series/parallel. The you can use small wire. If you use photocell panels, wire them for high voltage too. If yo
/archives//html/TenTec/2007-03/msg00095.html (10,782 bytes)

209. Re: [TenTec] 12 Volt boost ckts (score: 1)
Author: "Gary Hoffman" <ghoffman@spacetech.com>
Date: Tue, 6 Mar 2007 00:34:23 -0500
An excellent point Ken. I'll address it with the Editor. Not that I have influence or anything, but I write to the poor editor all the time :) Gary been on
/archives//html/TenTec/2007-03/msg00100.html (9,121 bytes)

210. Re: [TenTec] Is there a beefier 2N5301? (score: 1)
Author: "Gary Hoffman" <ghoffman@spacetech.com>
Date: Tue, 6 Mar 2007 18:59:02 -0500
Active cooling might well be an answer. Not just a fan, but how about a TEC device ? If there were wide enough interest I could perhaps offer a design as this sort of thing is what I do (thermodynami
/archives//html/TenTec/2007-03/msg00128.html (9,607 bytes)

211. Re: [TenTec] TenTec Digest, Vol 51, Issue 8 (score: 1)
Author: "Gary Hoffman" <ghoffman@spacetech.com>
Date: Tue, 6 Mar 2007 19:01:49 -0500
Agreed, you could run everything on 12 volts. That would work for many common situations. It would not work for my setup with scanners and commercial radios and computers, and....well you get the ide
/archives//html/TenTec/2007-03/msg00129.html (10,685 bytes)

212. Re: [TenTec] emergency back up power (score: 1)
Author: "Gary Hoffman" <ghoffman@spacetech.com>
Date: Tue, 6 Mar 2007 19:03:23 -0500
I like to use copper bus bar stock. Cut to length and drilled to fit battery terminals I have installed. You can often get this surplus for pennies on the dollar at surplus shops. copper that
/archives//html/TenTec/2007-03/msg00130.html (9,963 bytes)

213. Re: [TenTec] Is there a beefier 2N5301? (score: 1)
Author: "Gary Hoffman" <ghoffman@spacetech.com>
Date: Tue, 6 Mar 2007 19:07:06 -0500
a That is where a TEC design would come into play. You can keep that heatsink just as cold as you want. 73 de Gary, AA2IZ
/archives//html/TenTec/2007-03/msg00131.html (10,016 bytes)

214. Re: [TenTec] Is there a beefier 2N5301? (score: 1)
Author: "Gary Hoffman" <ghoffman@spacetech.com>
Date: Tue, 6 Mar 2007 19:50:20 -0500
It is interesting that most of us don't know how important the heat sink goop is, and how much of the heat transfer takes place through it. The two metal surfaces (heat sink and transistor) even if m
/archives//html/TenTec/2007-03/msg00134.html (12,211 bytes)

215. Re: [TenTec] Is there a beefier 2N5301? (score: 1)
Author: "Gary Hoffman" <ghoffman@spacetech.com>
Date: Tue, 6 Mar 2007 22:47:19 -0500
I'm sorry Ralph....I speak in techno-babble all too often ! A TEC is a thermoelectric cooler. As you probably know, if you apply low voltage DC to one of these babies, it pumps heat - making one side
/archives//html/TenTec/2007-03/msg00148.html (10,627 bytes)

216. Re: [TenTec] Is there a beefier 2N5301? (score: 1)
Author: "Gary Hoffman" <ghoffman@spacetech.com>
Date: Tue, 6 Mar 2007 23:35:39 -0500
Hi Jerry, Nope...a properly designed TEC cooler is very efficient. My designs usually operate at a COP of between 3 and 7. Its a common myth that TEC coolers operate at a COP of near unity or less. (
/archives//html/TenTec/2007-03/msg00149.html (11,510 bytes)

217. Re: [TenTec] TenTec Digest, Vol 51, Issue 8 (score: 1)
Author: "Gary Hoffman" <ghoffman@spacetech.com>
Date: Tue, 6 Mar 2007 23:38:17 -0500
Yes....a single inverter properly sized and thus with a reasonable load is most efficient.
/archives//html/TenTec/2007-03/msg00150.html (9,696 bytes)

218. Re: [TenTec] Is there a beefier 2N5301? (score: 1)
Author: "Gary Hoffman" <ghoffman@spacetech.com>
Date: Tue, 6 Mar 2007 23:43:34 -0500
That's right Jerry....and common practice. But better practice is to seal against moisture, which is what I do. Its not as though there is very much moisture, nor is there any water pressure. points.
/archives//html/TenTec/2007-03/msg00151.html (12,579 bytes)

219. Re: [TenTec] Is there a beefier 2N5301? (score: 1)
Author: "Gary Hoffman" <ghoffman@spacetech.com>
Date: Tue, 6 Mar 2007 23:45:42 -0500
A further comment is that many TEC coolers are used in fact as dehumidifiers. As such, they are available from the factory sealed against water. You must take further steps of course. But it is not s
/archives//html/TenTec/2007-03/msg00152.html (12,835 bytes)

220. Re: [TenTec] Is there a beefier 2N5301? (score: 1)
Author: "Gary Hoffman" <ghoffman@spacetech.com>
Date: Wed, 7 Mar 2007 14:38:38 -0500
Bill, Only use mica or the various pads if you require electrical insulation. They do not conduct heat anywhere near as effectively as the thermal grease by itself. If you do require electrical insul
/archives//html/TenTec/2007-03/msg00166.html (10,973 bytes)

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