Video Camera/transmitter on ebay

There seems to be a lot of really-short-range commercial stuff that operates on about 433.92 Mhz - car alarm remotes, wireless computer keyboards, etc. - I know that frequency is also an amateur-band frequency.

-dave w

You do not have the authority to interfere with anyone. Only authorized government workers can do that. However, you can tell the person to stop because it offends your sense of symmetry and ,if he doesn't, you will ask him to leave the launch area. Since you are the land owner's representative, you can do that.

Irrelevant if the equipment in question (transmitter and receiver) are poorly designed.

A 2.4GHZ transmitter could easily have an IF in the VHF range, some of which can make it through to the antenna--which could desense nearby receivers operating in VHF.

De-sense is a hard problem to combat in receivers. Even when there's adequate front-end filtering, significant work must be done to shield (for example) AGC lines and the AGC detector from stray RF fields, lest they sense the wrong thing, and turn down the gain on the front end.

Non-linear circuit elements in the output path of a VHF transmitter can easily generate *powerful* harmonics extending up into the GHZ. If you don't believe me, put a coupla hundred milliwatts into a step-recovery diode at 144MHZ, and look at the output on a spectrum analyzer sometime. You'd be amazed.

FCC certifications (and the matching Industry Canada certs up here) are there for a reason. Cheap RF equipment is often very poorly designed, with spurious emissions that can seriously screw up other users either in the same band, or other, unrelated bands.

The doctrine of "if it's only 100mW, it isn't regulated" is very band-specific, both in the US, and in Canada. You really can get fined, fairly heavily, even if you're only putting out 50mW. Imagine interfering with emergency services transmissions, for example.

I once got a call from a (polite but firm) Industry Canada/Department of Communications "sniffer". One of the amateur repeater transmitters I was responsible for had suddenly developed a spur (spurious transmission at something other than its nominal operating frequency) that was knocking out a commercial radio communications network used by hundreds of businesses in the Ottawa area. You can bet that I dropped what I was doing at my day job, and headed up to the site to turn the damn thing off. We weren't fined. But if it had happened repeatedly, DOC would probably have instituted an "action"...

Right you are. I think the remotes, keyboards, and such are designated as secondary users (i.e. not protected from unintentional interference from the primary user). Of course, a properly tested and certified Part 15 device can end up on almost anybody's frequency - I suspect there are exceptions related to life safety like medical devices and police/fire.

It's interesting that the manufacturers of that stuff picked an area of the 420-450 MHz band that is pretty close to the 432 MHz section used by amateurs for weak-signal work such as EME (Earth-Moon-Earth or moonbounce) and meteor-scatter.

Are we talking real, TV quality video here? Or just the typical, blocky, low-frame-rate webcam kind of junk?

I fly 200,000(+) miles a year on domestic air carriers....MANY (not all) have removed the airfones. When I inquired (and I have inquired about a half dozen times) I was consistently told that they were not getting enough use to justify the cost. They disappeared (as did plenty of other frills) within 2 months of 9/11.

Mark A Palmer TRA 08542

Bob Kaplow wrote:

9/11 showed us that cell phones work fine in aircraft. The biggest reason for the ban is that if you could use your cell phone on aircraft, you wouldn't use the $3.99 per minute airphone in the seatback that the airlines get a cut of the revenue from.

Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!

That sounds like flight-attendant-guesswork. My take is that the airfones are co-op'd by the service providers. They supply the phones and the airline supplies the headrests. The service provider manages everything and simply pays a cut to the airline. The airline is out no up-front cost, and no operating or maintenance costs.

I still see the phones on planes, just not on the newer models. The

777's I've been on had TV screens in the headrests.

Could it be you're seeing new planes? Or maybe older planes which've undergone regular maintenance/re-hab and the provider opted not to stay in the game?

Doug

They were on the 757's we flew this summer. I had a 12yo sitting next to me who was dying to use it, until I told him that I needed to see his allowance money up front first...

tah

Could Be!!!! I still would guess that there is no profit in them or else why would the provider opt out? ;-)

Mark

Doug

The FCC even has an enforcement bureau for broadcast stations now. I'm bustin' my big ol' backside trying to keep up with the latest changes. They have also upped the minimum fine on broadcast stations to $10,000.

John

Oh, yes, I agree, the profitability has gone out of them. Frankly, before cell phones proliferated, I seldom ever saw anyone use them, and now that everyone's got a cell/gsm, I never see them used.

I wonder if they ever made a profit.

These deals can propagate losses, too. The service provider can hook the equipment maker in with a promise of a cut of the action. Then the eqpt maker who loses his hinee on the deal, too.

Doug It always seems lucrative to get in "on the ground floor" of new ideas...until you find out how many of those deals only have elevators that go down.

Junky today, hi res tomorrow such is technology.

Arnold

I have a new cell phone that produce VGA quality photographs and eats up lots of transmission and band width. I bought the phone for the same price I paid for the crummy photo phone I bought last year. Seems they want me to take and use lots of bandwidth.

Soon we will have high quality real time video. If they did not want you to use it, then they would not sell it to you. After all, you will have to call another phone to transmit the video to which makes them very, very happy and me to - I own lots of phone stock.

Arnold

What capture card would be recommended for taking video from these type units and making an mpeg or other file type that could be shared?

What software would offer simple editing to chop out any unwanted video?

tim

Next time your on a flight, take a look at passangers with "cell phone hands free headsets on in the plane".

that date you mention is now why they all know they work now, and just like game boy will hide the fact they are using it while flying.

I'll let you know how the capture card that is being delivered tomorrow does got it off of e-Bay for bout $40.

[snip]

There's some truth to that. Part of it is simply tradition, I suppose. I can't deny that the original purpose of amateur radio to "advance the state of the art" has been passed by - especially when the FCC tends to prohibit novel modes of transmission until they've been investigated. It's hard to do significant research when you can't try it out for real. But then, back in the early part of the 20th century, auto racing was justified as "advancing the state of the art of the motor car." The big automakers still pour major bucks into racing, but it's now almost purely an advertising vehicle - when was the last time you heard about some innovation from NASCAR becoming part of a production vehicle?

transmissions.

In practice, you're probably right.

Again, you're probably right. However, if that 500 mW video is on a shared channel used for some critical purpose, and transmits from 10,000 feet so as to have an effective range of 50 to 100 miles, it WILL get some attention. Remember that at VHF and above, line of sight is more important than ERP.

The guys I read about on the ARRL page who lost their licenses for out of band operation were interjecting smart-ass remarks for a few seconds at a time on a police frequency with a 2 W handheld - and got caught.

WB9QLR

I pipe the output of the receiver right into my Sony digtal8 camcorder and then use firewire to connect to the computer. My new Dell system came with TWO firewire ports built in!

Regarding software, I am still using an old verion of Ulead's Video Studio ver 3! It works great, is fast and I use it more than my Adobe Premiere ver 6. It came free with my first firewire card and I think list price is like $99 or less. If you can find it on Ebay, it would be cheap!

Joe C.