Martin V

I just renewed my amateur license but don't have any idea what I can or cannot do. I got my license about 10 years ago and never put it to use. Now that I am getting into wireless cameras and airplanes I am wondering what I can and cannot do. I have a Technician class license and I also passed the Morse code test but don't know if that part expired or not.

My main questions are: What wireless video frequencies and powers can I use?. I have heard about 50MHz radios. What are their benefits?, Range?

One of my goals is to have a system with a lot of range so I can fly out of visual range and use wireless video, a GPS receiver and a system that will transmit other flight data in real time to a computer on the ground. Also looking at a programmable autopilot system to program a flight path for the plane to follow.

My brother pretty much has all the GPS and programming part of it figured out. I just need to figure out what I can and cannot do as far as transmitting frequencies and power goes.

Thanks,
Martin

rc bugman

My Feedback: (30)

With a ham ticket, you can use atv in the 420-440 mhz freg range which gives you max range for tx output. You can get a 1.5 watt ATV tx from PC-Electronics (hamtv.com) and receive the signal on a cable ready tv. This gives you rock solid video with an excellent range. A yagi receive antenna will further increase your range. PC-electronics also carries the text overlay board which overlays the gps information on the tv picture (also your call sign to make you legal). I use this setup in my univ research project with great luck and you get much better video than most of the systems in the 2.4 gig freq range.

Elson K2BUG

mr.rc-cam

You really need to review the Part 97 regs. Start here: http://www.arrl.org/FandES/field/reg...ules-regs.html

Fubar-One

My Feedback: (1)

In addition to that you can operate your plane on 50mhz. Range is the same but you will probably NEVER run into a frequency conflict at the field. Also, at least in my case so far, you get less hits from other sources. Generally, I can turn on the plane and not the tx and the servos dont twitch about like they do with 72mhz.
For video, 2.4ghz is LEGAL for Ham operators.

elevator_up

Oh boy, these regulations look exciting !

Rc Cam, I saw the article you posted on adding channels to your transmitter on "the other board". This was way cool !!

Dan, to operate on 3 meters is this just a matter of changing the crystals in tx and rx or is there more of an equipment change ?

Already got my HAM book, and started reading, I read that the shorter the frequency the longer the tx distance. So should there be a slightly better range with the 50 vs 72mhz, or is the difference to small to notice in this case ?

Fubar-One

My Feedback: (1)

If you mean 6 meters, yes there is more to it than just changing xtals. HOWEVER, in the case of my Futaba 9C, I can change the module in the back of the tx to whatever freq I want. I have a module for channel 38 on 72mhz and one for channel 1 on 50mhz. The receivers, however, must be either 72 or 50mhz receivers. Due to some issues with operating a 900mhz video system which completely overloaded the 50mhz Futaba rx that I was originally planning to use on my Kadet Senior ARF, I had to use one of my channel 38 Futaba rx's instead. So, when I fly my Kadet and my Ultra Stick on the same trip to the field, I just swap the tx module for the appropriate plane. Works great.

retnavycdr

My Feedback: (190)

A lot of good comments and information. We only have three of us at our club on the Ham frequencies, and the three of us are on separate channels! This IS the way to go.

Dr. Roger S. Stasiak
AMA 686005
KE0FI, WB6EQB

Martin V

Thanks for the info everyone.

Elson, what aproximate range are you getting with your setup?

rc bugman

My Feedback: (30)

Martin,

We are using the video signal to relay plane position and other GPS information back to a control center located in a trailer as text written on the video picture. Planes operate about a mile from the receivers (tv sets) coupled to 100" whip omidirectiona antennnas tuned to 425-439 mhz. Picture is rock solid. We make a video tape of the flight as backup for the data collected by a datalogger carried on board. Pilots are required to maintain a flight path within close tolerance of altitude and the altitude is maintained by a radio-link between the control center operator and the pilots.

Elson

kd7ost

Any of you guys try different antenna's with your RC gear? I fly with 72 and 50 mhz gear. The antenna on my 50 mhz unit, (6 meters) is actually a 1/4 wave antenna for 72 mhz. I think a move to turn the transmitter in to a AMA certified tech is in order. I think tuning the amp section to as near as the 1 watt allowed into a dummy load would be a start. Next, I plan to put a BNC coax connector on it and then connect the whole thing up to a 6 meter Yagi. The reciever on the plane would likely be best as a 5/8 wave di-pole with one element down the fuselage and the other down a wing. This would keep the null ends from facing the transmit source.
I'm wondering if any other Ham/RC pilots have tried any antenna combinations and have any results to post?

Dan/kd7ost

rc bugman

My Feedback: (30)

Dan - KD7OST

While the antenna measures at a 1/4 wave for 72 mhz, undoubtly there is a tuning coil attached to the antenna which makes it look longer to the RF signal, usually to a 1/4 wave on 6 meters. If you use a yagi, you increase the output of the antenna but the signal becomes very directional. A dipole on the rx increases sensitivity but you need to be careful about tuning to resonance because of the tuning coil on the rx which is included in the "length" of the antenna. In addition, the 5/8 wave antenna has a squashed pattern compared to the 1/4 wave so application is very important.

Elson K2BUG

elevator_up

Aside from being legally able to transmit on additional frequencies, having a Ham license allows you to use ham radio. Do you guys also have the radios and talk with other Hams ?

Fubar-One

My Feedback: (1)

My dad and I talk (well, when my truck was running) on 220 quite often. Also, we are playing with the idea of aiming a high gain yagi antenna at the field from his house to pick up our wireless video signals.
Talking 900mhz here, not 1.2 ghz so nobody freak out.

rc bugman

My Feedback: (30)

Actually, 1240 mhz to 1300 mhz is also legal to hams for video images. There has been a few comments that 1.2 gig is not legal

Elson K2BUG

mr.rc-cam

The issue has been that a sampling of the low cost imported "1.2Ghz" video systems has revealed that they are operating in the 1.1Ghz band. That is reserved for aviation navigation use and is off limits to us mortals, including hams.

elevator_up

... can we have a major rewind here !!!

I thought for the past eternity we've been lectured that 1.2ghz equipment is illegal. Now we are being told that it is not illegal, what gives ???[sm=confused.gif]

rc bugman

My Feedback: (30)

The FCC allocated frequencies for amateur use for video imaging are as follows:

50.1-54.0 mhz (6 meters)

144.1-148.0 mhz (2 meters)

222.0 - 225.0 mhz (1.25 meters)

420.0-450 mhz (70 centimeters)

902.0 - 928 mhz (33 centimeters) One of the forum's recommended vendors sells 900 mhz equipment which operates on 910, 980, 1010, 1040mhz. Only one channel is legal. Buyer beware.

1.240-1.300 ghz (23 centimeters, 1.2 ghz)

2.300 - 2310 ghz and 2390 - 2450 ghz (2.4 ghz) One of the forum's recommended vendors sells sells 2.4 ghz equipment which 2 of the 4 channels transmit on frequencies outside the legal frequency band. Buyer beware.

For those of you who feel that getting a ham ticket is too much trouble, perhaps you should operate on those illegal frequencies. That way, the legal hams who police the ham frequencies for illegal use and report that use to the FCC (as per agreement with the FCC) will not know that you are operating in the area without a license. Most license holding hams are very careful to adhere to the FCC allocated bands.

Elson K2BUG

yardflyr

To Rc Bugman. According to the FCC allocated frequencies the Spylinker 800mw system is legal to use with a ham licence since it operates in the 1.2 gig frequency. Yeah, I know I'm beating a dead horse but I just want to make sure since the system they have is a lot of bang for the buck.

yardflyr

To RcBugman or whoever has an opinion. Would value some insight on the subject. Thanks.

mr.rc-cam

I have not tested the 800mW system, but Spylinker's other "1.2GHz" systems seem to operate around 1.16Ghz. That is reserved for Aviation Navigation. Definitely not legal in the USA, even for a ham.

Hams may use 1.24Ghz to 1.30Ghz. So, if the Spylinker 800mW system is in that range then a amateur radio license would apply. Be sure to test each Tx, since they are not xtal controlled (They use a simple VCO design). The actual Tx operating freq may vary due to mfg tolerances.

RC-CAM

elevator_up

... Very interesting, I thought previous posts condemned all 1.2 units. I must of missed this fine point in one of the many previous posts, but just for clarity what you're saying is that ... Even though the manufacturer of the spylinker units say they operate within the legal limit, there could be some mfg variance that just takes it out side of legal limits ?

Well now that I know that according to the manufacturer, that they are legal for use, I'll open the box again and dust it off. I'm working on the ham license, hopefully by year end I'll then be legal.

If I try to validate the manufacturers claimed frequency, I'm not sure I'd even know where to go to get it tested to be sure it's within the allowable range ?? If it's not would it be that difficult to make the minor adjustment to the VCO design making it perfectly legal ?

mr.rc-cam

I would be interested in seeing where he says that his equipment is legal in the USA. Do you have a link?

When I wrote to Spylinker to report that his equipment was not operating in a legal North American RF band he responded that it was legal in his country only. Also, he was not concerned that it was a federal offense in the USA to use non-conforming RF gear and was not interested in making any changes to the design.

I suggest that you use a frequency counter and measure the RF to be sure it is operating in an approved RF band. I suspect you will find the same bad news that other purchasers of the low-end imported systems have found.

RC-CAM

Razorback58

My Feedback: (8)

OK, here's a dumb question. How do you go about getting a Ham license? I'd like to get one, but I don't even know where to start? Can anybody give me any ideas?

mr.rc-cam

Everything you need to know about getting a ham license is available at www.arrl.org. This organization is the "AMA" of ham radio.

Basically, you will need the technician class license for our application. The test is offered by many local ham clubs. The questions cover technical, operational, and safety issues. Cost is almost nothing (I paid $10) and the license is good for ten years.

Although you can just memorize the answers to the questions, like many folks do, I suggest that you attempt to understand what they mean. If you learn a bit while you study you will be better prepared for the real world issues that will be experienced when you attempt wireless video. Despite the advertised claims, getting good performance from them is not always plug-n-play.

I have said this before: Little old grandmothers have earned their ham ticket. There is no reason for an R/C'er {that is using license-required equipment} to not follow suit. Ignoring the legal issues, this is the respectful thing to do. Hams have serious investments in their hobby, just like R/C'ers, and they deserve to have others follow the RF spectrum rules.

kd7ost

http://www.qrz.com/ham/

Here is a site you can take the test at. It's a practice test site. Go to technician class to start with. You can take these tests over and over till you see the whole question pool and can pass the tests with greater than 70 percent all the time. I would recommend being able to get 95 plus routinely.

You can go to the arrl.org site mentioned above and do a search for your local club test administrator. Or, check your local electronic supply stores. (Not likely Radio Shack) They should know someone in your area in to Ham. They usually support the clubs very well and vise versa.

Then there is a token fee you'll have to give to your Volunteer examiner. (VE) It's about 10 bucks or so. The funds will most assuredly go into the local club. You won't have trouble getting help once you find your local Hams. Let them help you get squared away.
Many clubs teach classes for free to help newcomers pass the test.

Dan