2.4 Ghz JR Radio Transmitters [Archive]

mckaneorg

Dec 06, 2005, 11:25 AM

As most of you know, JR has released one of the many to come 2.4Ghz transmitters for aircraft. This will allow a specific id to associate to your plane, in allot of ways this will be the end of crashing someone else's plane with your transmitter. However, How does this affect video transmission? Will we all be forced to go back to 900 Mhz? I know that if I fly over an area with a huge concentration of wifi, I will get video blackouts in some areas.

Has there been anyone who has purchased the new JR radio? If so, what is your opinion? Secondly, does it conflict with any wireless video gear?

-j

pda4you

Dec 06, 2005, 11:30 AM

If you transmit on 2.4GHz you will likely have issues (with the video portion). I tested the system indoors with a wireless video vendor at SWAC. It caused issues on his stuff, but not the TX/RX of the Spektrum system.

Review here:
http://www.rcgroups.com/links/index.php?id=4936

Mike

clolson

Dec 06, 2005, 01:33 PM

Mckaneorg,

Do you have a link to the JR air system? I went to the JR homepage and couldn't see any mention of a 2.4ghz airborn system.

Thanks,

Curt.

mckaneorg

Dec 06, 2005, 01:47 PM

Mckaneorg,

Do you have a link to the JR air system? I went to the JR homepage and couldn't see any mention of a 2.4ghz airborn system.

Thanks,

Curt.

I saw it in one of the heli mags. Ill see if I can pull the publication out.

pda4you

Dec 06, 2005, 01:55 PM

It is not a JR system, but a Horizon Hobby brand - Spektrum.

Check here:
www.spektrumrc.com
http://www.horizonhobby.com/Shop/ByCategory/Product/Default.aspx?ProdID=SPM2460

Mike

JettPilot

Dec 06, 2005, 09:10 PM

Im willing to bet that putting a 2.4 GHZ video transmitter that close to a 2.4 GHZ RC receiver on an airplane will cause problems. The Spektrum stuff frequency hops, and will avoid the video transmitter frequency, but that only goes so far. If the video transmission is strong enough on the same band, it can overload the receiver and render it useless no matter what frequency it chooses...

Transmitters next to recievers on the same band are bad news. I be really careful testing that before I flew it.

pda4you

Dec 07, 2005, 09:32 AM

The Spektrum stuff frequency hops

Nope it does select two open channels, but does not hop after that.

Transmitters next to recievers on the same band are bad news

Yep, for sure! Just use 72MHz for these 2.4 systems.

As I indicated thankfully the 2.4 transmissions didn't affect my RC stuff, but my TX sure affected the video.

Mike

VBSuperMaxx

Dec 07, 2005, 10:16 AM

I am going to do testing for our group of flyers. Our LHS was a lotted 2 only 2 of these systems. HH is limiting LHS' to 2 per store because of pre-demand.

I am getting one and will be testing it. I am not into video like you guys here. But this system will be put through high density testing at a golf dome, and at our field.

If it works well, and I have a feeling it will, it will change the way LHS sell radios. It will cause 72mhz to be phased out ....may take years , but it wil happen. No longer when a newbie shows up , will you have to worry about shoot-downs. the benefits are obvious, but it will take time to warm up to the curmudgeons in this hobby.

the real test will be, if HH allows the receiver technology to be copied by aftermarket companies, so they can create a price war. If no one else can produce related and compatible equipment, it will stay just another brand specific one-off. And then it will go nowhere. A lot like the Polk Seeker , one-off, and it took years for the "big guys" to embrace the technology.

Just my opinion, I hope it goes well. It remains to be seen how it performs. I got a feeling I will be whacking a trainer or two finding out it's "real" range.

typicalaimster

Dec 07, 2005, 10:39 AM

I've reserved one of the Spektrum radios last month. Like Mike (PDA) said the Spektrum picks two channels that are free of interference. So far these are for park flyers only. I plan on testing the range in one of my planes as soon as I get the radio. If any of you have wireless networks in your house then you already know the cause and effect. The BWAV system was so powerful, it was knocking my laptop offline. This was until I switched what channel my BWAV system and wireless network was using.

The idea would be to turn on your 2.4 ghz equipment first. The very last thing to turn on would be the 2.4 ghz Rx and Tx for your plane. Why? The Spektrum folks state that the RX and TX will find 2 unoccupied channels and use those. If you turn on the other 2.4 ghz equipment first, the Spektrum radio will seek out something clear.

Range on these things have been tested by someone up to 0.7 miles. There is a big debate in the Electric's forum and on RCU about how far these things will really go. I think the best answer was no brand name states how far their radios will go. Once again I'll be placing this thing into one of my planes and testing it out. If I get 2kft out of it, then I'm happy!

VBSuperMaxx

Dec 07, 2005, 11:00 AM

I will try it by flying a foamy in a large farm field ...and flying it until I lose it.

If it gets the 2k range you ask for , it should be good enough for a glow trainer. The connections/pc traces might not handle the current of standard servos but that is easily rectified.

Where this thing could really shine is in the Dome indoor environs. I will play with it, and it will probably exceed expectations. I am going to go do some reading.

pda4you

Dec 07, 2005, 11:14 AM

There is a big debate in the Electric's forum and on RCU

Link please - I am curious and didn't find it when I searched.

Mike

typicalaimster

Dec 07, 2005, 12:24 PM

There is this one...

http://www.rcgroups.com/forums/showthread.php?t=431185

http://www.rcuniverse.com/forum/m_3474250/tm.htm

typicalaimster

Dec 07, 2005, 12:33 PM

If it gets the 2k range you ask for , it should be good enough for a glow trainer. The connections/pc traces might not handle the current of standard servos but that is easily rectified.

I'm able to GPS track my plane while I fly it. It's simple for me to control say the camera on the plane via the Spektrum system, while flying the 72mhz system. I can fly out on the 72mhz system until I lose control of the Spektrum.

Most of the people out at our field fly within a 1000' point of perspective. You figure some of us were already flying GWS receivers with a suggested 500' range.

JettPilot

Dec 09, 2005, 04:46 PM

The Spektrum folks state that the RX and TX will find 2 unoccupied channels and use those. If you turn on the other 2.4 ghz equipment first, the Spektrum radio will seek out something clear.

The problem with having a 2.4 GHz transmitter on the same band as the 2.4 spektrum reciever is that it will overload the reciever and cause it desensitize. So even though the Spektrum may choose two clear channels, its sensitivity might be so bad with a 2.4 GHZ video transmitter running in such close proximity to the Spektrum reciever that the range might be horribly short or even unflyable.

This is just a guess on my part, but an educated one as I have been playing with radio for more years than I care to admit to :o

I am anxious to see everyones results on this.

JettPilot

pda4you

Dec 09, 2005, 06:08 PM

This is just a guess on my part, but an educated one as I have been playing with radio for more years than I care to admit to

The video was a mess when the DX6 system was on. It reaked havock with the video transmission.

The really good news is it did not affect control of the DX6 system at all.....at least in my tests (for a few minutes) did not.....

So no question it will not be an option to equip a plane with the 2.4GHz spektrum system and 2.4GHz video systems....bad idea.

Mike

mckaneorg

Dec 14, 2005, 08:10 PM

The video was a mess when the DX6 system was on. It reaked havock with the video transmission.

The really good news is it did not affect control of the DX6 system at all.....at least in my tests (for a few minutes) did not.....

So no question it will not be an option to equip a plane with the 2.4GHz spektrum system and 2.4GHz video systems....bad idea.

Mike

I thought that might be an issue. :)

typicalaimster

Dec 14, 2005, 10:44 PM

Did you try moving the receiving antenna on the video end away from the Spektrum? I had a problem with my laptop's wireless card walking all over the video. The solution was to move the laptop or turn off the wireless card all together.

typicalaimster

Dec 15, 2005, 11:29 AM

I just picked one of from the LHS. The rest of my equipment is in transit from Az to DC. I won't be able to test for a few more days. However I'll be able to mount the radio equipment in my plane. I won't have a ESC, Motor or Camera until Friday at best. It's starting to snow here so I'm not in a big hurry.

mckaneorg

Dec 15, 2005, 11:40 AM

I think its a great toy for the hobby folks. But for industrial use, its not useful from the emails I have been getting from others using it. I think being able to communicate to a UAV thru a MAXSTREAM modem might be a good solution since each node is controlled by a 3 digit alphanumeric code over 900Mhz. Now they have a unit that will range out to 40 miles!

I haven't started developing in this yet although I have had some discussions with Walt at GPSFLIGHT regarding the idea. It could be a new way to control the VERY EXPENSIVE systems you have flying in the air. If you are in for thousands upon thousands of dollars in just the airframe alone, it might not be a bad idea.

If you have a slowstick... Well. 72Mhz it is! :)

-j

typicalaimster

Dec 15, 2005, 11:53 AM

It's actually rather simple to send the data up the maxtreams to the plane. They even have $30 servo controllers out there you can buy. I just haven't bugged my friend about putting together software for it. I wish I knew more VB or C+ so I could write something.

mckaneorg

Dec 15, 2005, 12:43 PM

typicalaimster

Dec 15, 2005, 10:04 PM

I sent you a PM

Fieldruts

Dec 19, 2005, 12:13 AM

hmmss... I will run a 900 and a 2.4 fhss system and not worry about confusion and cross flood.. but then again.. seemed simple a solution... oh.. did I tell you about the WIMax stuff... ;-)

maybe we just all need bridges...;-)

lvspark

Dec 19, 2005, 02:22 AM

Who says the maxstreams are not for a slow stick??? :D
http://www.rsnw.com/sss.wmv
This was a windy test flight with a SS from the junk pile, a laptop and game joystick..
I should have the futaba trainer port (non pc) version done within a month or so...

mckaneorg

Dec 19, 2005, 11:31 AM

Which servo controller are you using?

typicalaimster

Dec 19, 2005, 09:43 PM

I just had positive results with the BWAV system and the Spektrum. You have to first power on the BWAV system then REBIND the Spektrum. Just don't place the antenna on top of each other. I'll post a video when it's finished.

typicalaimster

Dec 19, 2005, 10:18 PM

Here is the video (http://www.zwei.net/video/Misc/SpektrumAndBWAV-HPB.wmv)... As you can see you almost have to place the antenna of the Spektrum on top of the BWAV receiver.

Mr.RC-CAM

Dec 20, 2005, 12:41 AM

You have to first power on the BWAV system then REBIND the Spektrum.It is conceivable that other folks will be flying Spektrum-like R/C systems at the same time. Some may even power up after you are airborne, so there will be no chance for wide area binding. What are the expected interference issues in that situation?

There is one local schoolyard that I cannot use my 2.4Ghz video system at due to interference from nearby household wireless networks. So, I am concerned about the Spektrum type R/C systems just causing more headaches.

typicalaimster

Dec 20, 2005, 01:03 AM

There is one local schoolyard that I cannot use my 2.4Ghz video system at due to interference from nearby household wireless networks. So, I am concerned about the Spektrum type R/C systems just causing more headaches.

Good point, Good point. I thought of that right after I made the post with the video. There are a few places around here where I have a very short range with the BWAV system due to the 2.4 ghz routers in the area. I have this feeling that I'll be rebinding as part of my range check in those areas.

mckaneorg

Dec 22, 2005, 10:21 AM

That is very interesting. This poses another question.

What if there is a glitch in the electrical system. For instance, If the heat shrink tubing was exposed and the battery started to short. Of course there would be more problems than just getting a radio reciver but in this case it would go off and then on. Once it does that, does the radio not look to a transmitter to marry to? Lets say perhaps you have 1 other person with this radio in the field. Is there a possiblity of getting married to the wrong transmitter? (No divorce jokes please! :) )

I dont have a unit to test yet otherwise i would short out a battery just to test the theory.

Also is it possible for other 2.4Ghz systems to blank out the receiver in such event? On the ground its no big deal but I think its possible it could happen in air.