cobrajocky

I know that I am not the last 72'er left and I doubt that my reasons for staying with 72MHz radios is unique; but two of the major reasons are - 1) I have too many great 72MHz Rx'es to just toss, and 2) Spectrum Receivers are too damn expensive. I do have and love processor based radios, I have several 72 Hitec's and Airtronics, my last new one a RD8000. But 72MHz receivers from major and reliable brands are dirt cheap (just bought 4 Ultra-ultra light weight 4ch Auto-Switching Corona's for Depron and EPP EP 3D and combat planes, for $14 BUCKS New!! 6ch were only $19!

Now I've seen a few references to supposedly "compatible" spectrum receivers on primarily Hong Kong sites (one I'm sure you know who I'm refering to) but frankly didn't bother investigating considering the source.

Are there any 100% compatible "after market" 2.4 spectrum receivers out there? Who are they compatible with? What do they cost comparatively and has anyone had experiences with them? In other words - WHO WHAT WHERE!!??

I'm particularly partial to my Airtronics RB8000 72, and if there are any compatible 2.4 RXes available for the RDS8000, that's where I'd like to go.

Or, is this not likely to ever happen (after market cheap compatible RXes like we have for 72MHz)? And why? (If that's the case, I'll never switch ..... but then again, thank you to all those that switch, I like having the 72 band all to myself.)

My wallet is ready .... if.

BarracudaHockey

My Feedback: (11)

Not currently, the protocols in use are proprietary and no doubt patented so I doubt you'll see knock offs in the states.

e-sailpilot86

I would say it is highly unlikely you will find an aftermarket product for any spread spectrum radio system. Engineers communicated between each other a lot on those radios that were made and probably designed in China to have cross compatibility. Or both receivers use a common part. The fact is, spread spectrum is much more heavily engineered, there is no standard and probably will not be a standard established (aside from FHSS and DSSS methods) like the 72 MHz band had. 72 MHz modulation was/is fairly easy to follow the standard. 1 to 2 ms pulse width (may be off but close enough) modulation, and a series of pulses making up all the channels, then it resets back to channel 1.

Spread Spectrum works similarly with our wireless routers, in that they have to follow FHSS or DSSS, but they have a suggested IEEE standard to follow so other brands can usually communicate with each other okay. Because there is no prime standard for sending out a low bit-rate r/c signal, there may not be an incentive to establish a strong standard.

cobrajocky

e-sailpilot86,

I suspect that the big reason it appears all the companies (Futaba, Airtronics, JR, Spektrum etc.) have all taken different design or technology routes and likely proprietary ones, is a simple one. They probably have been fed up for years with companies like Hitec, Castle, BlueBird, GWS, Corona, etc. taking away their business of selling extra receivers; it's the Inkjet Printer replacement cartridge thing of RC radios. Pretty sneaky, I'd say.

And if a few "compatibles" do come along eventually though, I can only see Futaba of all of the companies, being able to afford a "Bigger Gorilla" law firm, like HP and Canon has, to sue the "copy cats". So maybe there is some hope in the future.

Till then though, I'm not loosening my grip exclusively on my cheaper to use and buy more RXes 72Meg radios. Besides, with all the fad buying of the spread spectrum radios in my area, I'm finding I have more private use of the whole 72 band 8^ ))

On a side note - I'm hearing from a few of my fellow glider flyers that have switched to 2.4 of various brands, that they are complaining of shorter range with certain 2.4 radios than they got with their 72's. Airtronincs, JR and Spektrum in particular have been named as poor distance performers.

Have you heard or experienced this?

onewasp

websterphreaky

"Have you heard or experienced this?"

A resounding NO!!!

Out of sight range on Spektrum/JR-DSM2.

IF you like to fly in torrential rains then it is a possibility.
It sounds as if the "rumor" may have been created by some 72/50 MHz recalcitrants. [X(]

BarracudaHockey

My Feedback: (11)

I've gotten a 2.6m sail plane as high as I could see it with a glitch counter on it, aimed the antenna straight at it, and didn't loose signal.

jcccc

I'm with you Websterphreaky. I'm staying with 72Mhz and the ability to use any other manufacturer's 72Mhz RX with my TX. I like that about 72Mhz and that's why I haven't switched to 2.4Ghz. The only exception to that is the BnF/E-flight/JR/Spektrum compatiblity.

JC

onewasp

ONLY if you are non PCM as well as 72MHz.
That's sort of a long way back for many of us. But to each his own.

carrellh

What I have seen on the 'Hong Kong' sites are transmitter module/receiver combinations. The modules fit into Futaba, JR, Hitec, and other transmitters.

The Assan (to name one, no reason to be secretive) transmitter module will not communicate with receivers from anyone other than Assan. Assan receivers do not communicate with transmitter modules that are not Assan.

Once a person chooses a 2.4 path, he is stuck with it unless he is willing to start at square one again.

Eventually FCC will sell the 72 mhz band and we will be forced to change. Hopefully that is quite a few years away. I have three or four NIB Hitec receivers and a few used ones that currently do not have planes.

jcccc

How generous of you. Thank you.

Jc

dirtybird

My Feedback: (5)

I wonder if those company's ever had any qualms about the way they ripped off the initial designers of the PPM system?

carrellh

Probably not.

cobrajocky

I know two guys who have experienced it (less range) first hand. One flies a 2m Vista with a new Airtronics RDS8000 and noticed the plane "wandering" seemingly losing full control when it's a "speck" (he estimates 1.25 miles up); he went back to his RD8000 (7.2 version) and the problem disappeared. Also know a guy out in Palm Springs that lost control and literally "lost" his 3.5M motor sailplane - he was using a Spektrum 6ch (don't know the model).

So there! First had reports.

cobrajocky

If you did some research, you'd know that PPM was a technology that was DoD developed years before and "open domain" and anyone could use. Oops, got foot in mouth syndrome, huh?

cobrajocky

I know for a fact that JR makes radios for other companies to brand, so I suspect that the "BnF/E-flight/JR/Spektrum compatibility" is answered by the theory that JR is making all of them. JR is considerably bigger than Spektrum and E-Filght. A guy I've talked to at Global told be that when he visited the JR factory a while back, he saw an other brands radios being made on the same assembly line, just with cosmetically different "enclosures".

BarracudaHockey

My Feedback: (11)

LOL thats 6600 feet. I'll call bull dinkies on that

cobrajocky

Odd, Airtronics is claiming 2+ mile range on the new 10 channel Spread Spectrum radio. Would you prefer Catsup on your "bull dinkies", or rather have them on your Corn Flakes for breakfast???

Ps. the guy that flys the 2m Vista is a propulsion engineer on the Global Hawk UAV, I think he has a good handle on estimating distances ..... better than yours as a Heli toy flyer.

carrellh

Why would a propulsion engineer be any better at estimating distance than a toy heli flyer?

BarracudaHockey

My Feedback: (11)

I'm actually debating the fact that he can see a 2m sailplane at over 6000 feet. Maybe his calibrated eyeballs work better than mine though.

carrellh

I agree. Most 2 meter sailplanes have 620 to 680 square inches of wing area. My trainer has 888 square inches and my Uproar has 975. I've never tried to look at them from over a mile away but I'm pretty sure I would not be able to see them.

jcccc

Yes, I have no doubt that that is true. In some form or another it's called licensing. I merely included the 'compatibility' phrase in my post to be more accurate about the touchy subject of 2.4Ghz compatiblity and the lack there of.

jc

Hemikiller

My Feedback: (125)

Yeah, it's rough when you have competition for people's hobby dollars. I used to "enjoy" paying $70 for a R127DF receiver before Hitec came on the scene in full force. Hitec really stomped on some major toes when they started selling their RXs at reasonable prices, like $50 for their Supreme RX.


You can bet on that. I'd be more than surprised if the various technologies they have used/created are not fully patent protected.



I'm with you on using the 72mhz stuff. The fewer tags on the frequency board, the better it is for me. 72mhz stuff is at bargain basement prices now and I've bought what I need for the foreseeable future.

dirtybird

My Feedback: (5)

Right.
But the application and the servo that made it possible for our radio control was developed by Doug Spreng and Frank Hoover.
Unfortunately they never bothered to patent it. Possibly because when Futaba came out with its first stuff it was absolute junk.