RF design Mag article

IIRC, it was in RFD in early-mid 1989. I know two hams who followed the article and it all went very well.

I know I have that magazine, but all the RFDs are filed away in big boxes at the back of the barn. If nobody else can find a handier copy, I can provide it, but it may be a couple of days away.

Barry Lennox

March 1989, Pacholok, "A Microwave Oven to Amateur TV Transmitter Conversion," pp48-55.

I've got a photocopy I could scan -- what format, and where do you want it?

Best, James Arthur

So, how do you get a Ham-legal signal out of a MOT maggie? I'd assume an exceedingly clean DC supply, filament regulator, and tuned output, but isn't the frequency determined by the cavities? In the USAF, I worked on jamming transmitters, and they had tunable magnetrons - there were actual metal pins that they shoved in and out of the cavities to change the transmit freq. of the maggie.

Can you pull it, a la crystal, by changing the plate voltage, or the magnetic field, or something?

Thanks, Rich

Most countries allocate the "13cm" band (actually 2.3 to 2.45 GHz) for shared ham/ISM operation. So an MO maggie works. You can tweak them a tiny amount, maybe 5-10 MHz, by load mismatch and voltage. IIRC, a "Reike Diagram" a variation on a Smith Chart, shows how much they can be pulled.

There are also tunable maggies, as you note, usually by metal slugs that can be moved in and out of the cavities, but there's also voltage-tunable maggies.

However, all those are infinitely more costly than an ex-MO one!

Barry Lennox

James, any chance you could post a pdf to abse?

Regards,

Mike Monett Antiviral Antibacterial Silver Solution:

Dunno. I scanned it @ 600 DPI, in Wang-viewer compatible LZW-compressed .TIFF (the viewer, Start->Accessories->Imaging, comes standard with Win98). It's kind of large -- isn't 3.5MB a little inconsiderate, even on a.b.s.e.?

I could certainly e-mail it to anyone interested, and am open to posting ideas.

Best, James

Downloading from abse is by user choice, so it's not like sending spam to everyone's mailbox. As far as bandwidth concerns, 3.5 MB is insignificant. The p*rn groups post thousands of files per day.

Here is another service I haven't tried but looks easy. I think it was recommended by someone in s.e.d.

Regards,

Mike Monett

Antiviral Antibacterial Silver Solution:

But that's really the issue. There is a relative handful who'd actually want the article, yet to post it to a newsgroup means the file has to be shifted around to all the newsservers, and takes up space on all those newsservers, regardless of whether anyone using those newsservers is actually interested.

The fact that the p*rn and illegal files are already cluttering things up is irrelevant, because it is the notion that "a little bit can't hurt" that's gotten things to the current situation. "Let someone else's resources take care of things, I don't care." If someone had said years ago "a 3.5meg file is a bit inconsiderate, I better use a different method" and it stuck, then we wouldn't have the drain of resources (and the notion that Usenet is full of illegal files and p*rn).

That burden of binary files via newsgroups is some of the reason ISPs are turning off the newsgroups. "It uses up resources, but few are using it...". Text traffic may be significant enough, but it's dwarfed by the binary traffic. Yet for that load on the resources, few are going to take advantage of each specific file.

Binary newsgroups may have made sense in the early eighties, when Usenet was still transported over phone lines and it was aimed at those who didn't have an arpanet connection. Plus, at least back then the files were relatively small and related to the discussion newsgroups. Now, virtually anyone who has newsgroup access also has access to ftp and the web and even email. There is little reason to make use of binary newsgroups, except it's more "anonymous" and someone doesn't have to pay their ISP if there is a lot of demand for the file from their website.

People don't grasp this, and then turn around and complain that "google doesn't carry binaries" and that the binary newsgroups are flakey, because they get "parts 1 and 2, and 4 and 5, but the rest are missing, can you repost it...". But if the proper method was used in the first place, the problems wouldn't be there.

Remember, google isn't the only place that doesn't carry binary newsgroups. They are a resource hog, so many ISPs, those who aren't turning off the newsgroups, choose to not carry them (which is why binary newsgroups are in separate hierarchies, making it easy for an ISP to cut them out). So there isn't much use posting to a binary newsgroup "for wide distribution" if people can't get those newsgroups.

I would say the proper way to do things is to stick it at an ftp or website, because then it is more available but traffic is only limited to those who are interested, yet as I keep telling people who send me unsolicited 10meg files via email, the receiver can choose when to download it, instead of trying to check their email and having to wait while a large file is downloaded.

Michael

Send it to me and I'll put it on one of my websites for a few weeks for you. (Or longer, until I need the space.)

Thanks Michael, that's a very generous offer.

After reviewing the options, I think I prefer to e-mail the file to those interested. That way I won't crowd other traffic off the a.b.s.e. servers, and I can respect the copyright-owner's rights too. (e-mailing a few copies to interested parties is certainly "fair use," and allowed under copyright law. The effect of posting the thing, however, isn't as clear to me. I prefer to err on the conservative side.)

The file's 3.5MB, which uuencodes to a 5MB e-mail attachment. It's viewable with the standard WinXP "Windows Picture and Fax Viewer," or the "Imaging" accessory that comes standard with Win98.

Thanks again for the offer, and best regards, James Arthur

snipped-for-privacy@yahoo.com wrote: > After reviewing the options, I think I prefer to e-mail the file > to those interested. That way I won't crowd other traffic off the > a.b.s.e. servers, and I can respect the copyright-owner's rights > too.

Hi James,

Thanks for your kindness. To avoid publishing my email address so spammers can harvest it, could you email a copy to the address on my contact page?

Mike Monett

Antiviral Antibacterial Silver Solution:

See if it gets any smaller reduced to grey-scale and converted to jpg. If it's less than 1 meg it's OK.

- YD.

It's already in 1-bit-per-pixel format, and compressed about 6:1. Only 6 pages, the file's big because of the scanning resolution, which was needed to capture tiny characters used in some equations.

I've not found any benefit to using grayscale for .JPGs of documents

-- the files are often actually larger, and not as clear. Also, we need a multipage format.

I can send you the PaperPort .MAX file if you'd like -- 1.6MB -- or a

Best, James Arthur

Done. Apologies in advance for the HTML -- it was my first go with Outhouse Express.

James

I've just used a mangled email addy here for the last year or so, and I only get about 3 spams a week, none relating to electronics

martin

Okay all, I've re-scanned at 300dpi, and can offer: 1) 600dpi scan, .TIF, 3.5MB ==> 5MB e-mail attachment. Quality = good. 2) 300dpi scan, .TIF, 1.2MB ==> 2MB(?) e-mail attachment. Quality = fair. 3) .ZIP file containing .PNGs of each page, 934KB total, ==> ~1.3MB e-mail. Quality=fair.

James Arthur

I'd say, that's not a problem, it's what the binary groups were designed for. I've read that an ISP's newsgroup bandwidth is burdened more by folks downloading p*rn, movies, music, etc, rather than by the newsgroup feed itself. We know an ISP sets very short retention times and file MB limits for most of the binary groups, and saves on hard-drive resources that way.

Yes, if available, which isn't always the case. abse is handy, one can carry on conversations, etc., intermingled with files.

Hi James,

Thanks - got it. Unfortunately it's a little too big for my Base64 decoder, so I will have to write my own so I can retrieve it. There are plenty of decoders on the web, but they can take up a megabyte or more, and I don't feel like wasting that amount of space for a routine that only takes 654 bytes in assembly, plus 8 bytes of stack:)

If you just started with Outhouse, you might be interested in another alternative rather than accept the constant risk of some hacker figuring out a way to install a rootkit. Geminisoft has an excellent email client called Pimmy that allows unlimited email addresses with arbitrary servers. The free version is available at

I get a bunch of disposable email addresses from

The nice thing about Pimmy is it has no native decoders, which means nobody can send you an email with an embedded virus and have it activate as soon as you open the file. So it is impossible to get infected with an unsolicited email.

The email address on my contact page is encoded to hex. This completely foils email harvesters since there are too many different ways to encode addresses, and they don't want to waste the time. There are plenty of other victims to get without any hassle. So I never get any spam from the contact page, except unwanted junk from vendors.

The warning notes on my contact page are mainly for vendors and job hunters. They like to send 10 megabyte product brochures or 5 megabyte resumes in pdf and doc format. And html should simply be banned anyway for email since it is so easy to embed javascript or Visual Basic commands that effectively can do anything with your computer. Except if you are using Pimmy, which won't decode or execute anything, including html:)

Anyway, thanks for the article. I'll get busy converting my Base64 routine to replace the one I downloaded that can't handle large files. Should be trivial to do. Regards,

Mike Monett

Antiviral Antibacterial Silver Solution:

I used to get a lot more spam by posting an address on the newsgroup. But I get zero per year using a hex-encoded web address. Regards,

Mike Monett

Antiviral Antibacterial Silver Solution: