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HomeAircraftHelicopterMain Discussion › Horizon to discontinue selling JR radio systems on 72 MHz ????
03-09-2008 04:27 AM  10 years agoPost 41
RESQMAN911

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Canton, GA

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Can you tell me exactly what problems you have seen with 2.4, I can honestly say I have only see one true problem that was attributed to a 2.4 system.

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03-09-2008 04:09 PM  10 years agoPost 42
JuanRodriguez

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The Villages, Florida

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This is straying from the topic a little but yet, related to the discussion.......
In response to this......
Can you tell me exactly what problems you have seen with 2.4, I can honestly say I have only see one true problem that was attributed to a 2.4 system.
Here is a quote from a friend who has his finger on the pulse of the RC industry and whose opinion I trust......(different person than the LHS owner)

"Here is where the problem will be. The Futaba engineers and Airtronics engineers know that as they have more systems in the field, the JR process will struggle in that it will have trouble finding 2 open frequencies with other radios doing their frequency hopping every 3-5 milliseconds. AT that rate it doesn't take long to cover the band and the Spektrum radio will take longer to find their open channels."

What that means is that if members at your field have two or more Futaba systems on at the same time, your JR Spectrum system might have trouble finding available frequencies to lock onto.....my understanding is that Spectrum needs at least 2 or more available frequencies in order to bind ???

I have almost always been a JR man but I'm starting to re-think that position.....

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03-09-2008 04:44 PM  10 years agoPost 43
pH7

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Sterling Heights, MI - USA

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The person you are quoting may be very experienced, but doesn't understand the DSM and DSM2 technology. The frequency hopping systems may use the channels, but they cannot "occupy" a channel, since that is unique to the DSM method. The limit will be 40 Spektrum transmitters active in the same locale. The frequency hopping systems will not limit the DSM transmitters. See this FAQ from the Spektrum web site: Can 2.4GHz Frequency Hopping Systems interfere with Spektrum equipment?

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03-09-2008 05:48 PM  10 years agoPost 44
Dr.Ben

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Richmond, VA, USA

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Can we have a show of hands of how many people think there could be 40 or more Spectrum owners that would like to use their radio at the same time- in the pits, flying, or otherwise, at IRCHA this year?

I'd like clarification of this question: When a Spectrum system looks for an unoccupied channel, lets say one or more (dozens in reality at an event such as IRCHA) FAAST systems is/are hopping across that same channel. If the hop occurs when the Sprectrum system looks at that channel, does ANY delay AT ALL occur in the time the hop is seen and when the Spectrum system will occupy that channel? At what point does a HIGH FASST load in the same locale as Spectrum begin to slow the rate at which the system can recognize the channel as being uncluttered? How many closely spaced hops by multiple FAAST systems does it take before a channel is viewed as occupied by a Spektrum system?(edited 3/10/08

Ben Minor

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03-09-2008 07:46 PM  10 years agoPost 45
Ace Dude

rrProfessor

USA

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No, merely a statement noting the factual information posted by the Horizon rep, that only CRYSTAL based radios are affected . . . which quite obviously does NOT include synth sets . . . read the notice!
JR was the last to the table with a synth module/radio. Heck, even HiTec beat them to the marketplace. I think it's a pretty safe assumption that 95% of JR radios out there are non-synth radios.

  

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03-10-2008 01:31 AM  10 years agoPost 46
pH7

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Sterling Heights, MI - USA

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When a Spectrum system looks for an unoccupied channel, lets say one or more (dozens in reality at an event such as IRCHA) FAAST systems is/are hopping across that same channel. If the hop occurs when the Sprectrum system looks at that channel, does ANY delay AT ALL occur in the time the hop is seen and when the Spectrum system will occupy that channel?
I believe no delay, because the Spektrum is only looking to see if some other Spektrum is using the channel. FAAST are basically ignored. Even if it has an effect, the FAAST systems are only on one channel for a very small number of mili-seconds. The situation you are talking about only happens once in a session, when the Tx is switched on, so such a tiny delay would not be noticeable even if there is one.

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03-10-2008 01:39 AM  10 years agoPost 47
tadawson

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Lewisville, TX

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JR was the last to the table with a synth module/radio. Heck, even HiTec beat them to the marketplace. I think it's a pretty safe assumption that 95% of JR radios out there are non-synth radios.
And your point is what, exactly? This has nothing to do with what they do or do not continue to sell - 72MHz Synth gear is fully compatible with 72MHz crystal gear, so if the synth modules and RX's are still available, this is a total non issue . . . . .

? ? ? ?

- Tim

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03-10-2008 02:30 AM  10 years agoPost 48
Ace Dude

rrProfessor

USA

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And your point is what, exactly? This has nothing to do with what they do or do not continue to sell - 72MHz Synth gear is fully compatible with 72MHz crystal gear, so if the synth modules and RX's are still available, this is a total non issue . . . . .
My point is that if JR discontinues all their crystal gear they won't have much left....

By the way, I was talking to the Castle folks at a recent trade show regarding 50MHz Berg receiver availability. Lets just say it's a safe bet it's never going to happen. The told me that 72MHz sales are down 80%.

You can hold on to your boat anchor technology all you want, but the handwriting is on the wall.

  

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03-10-2008 02:40 AM  10 years agoPost 49
Ace Dude

rrProfessor

USA

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I have almost always been a JR man but I'm starting to re-think that position.....
The grass isn't always greener on the other side.

  

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03-10-2008 03:16 AM  10 years agoPost 50
NZ_Neil

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Auckland, New Zealand

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I was at an Indoor Heli Funfly on Saturday Night here in NZ and a lot of guys had small foamy helis and planes in the $100 - $200USD pricing bracket and these models all came with transmitters on 2.4ghz.

2.4 is now clearly taking over the low end "Toy market" very fast I was very surprised.

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03-10-2008 03:33 AM  10 years agoPost 51
Juggernaut

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Canada, Great White North

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I work in the radio field, 900Mhz, 2.4GHz 5.1,5.3 & 5.8 GHz bands

I myself have a 72MHz radio, for a number of reasons.
1) it's a licensed band, reserved for RC aviation hobbiest
2) As frequencies go up, the transmitted power does down, over distance
3) Lower frequency, better RF penetration

Now the 2.4GHz band
1) unlicensed band
2) any one and everyone can use this band, main reason this band is unlicensed, interference due to microwave ovens, yes microwave ovens operate at this frequency (check for yourself)
3) On thing not noted, not only are the spectrum radios using this band, also BlueTooth(cellphones have this capability), as more people shop up at the heli field with Bluetooth enabled uses a part of the frequency spectrum. Other devices not on the heli fields, but around the house, cordless phones, wireless mouse & keyboard, WiFi. Now don't forget your neighbor's, are also using these frequencies.
3) Higher frequency, requires line of sight
4) Multi path interference, ( same signal one delayed due to reflection, remember the old days of TV antennas, and you saw a ghost image)
5) Very small antenna, why do you think they have two antenna systems, placed 90 degrees apart, ( signal polarization ).

I'm not saying one is better than the other, but describing the Pro's and con's

To better understand what is happening in the airwaves, a spectrum analyzer, at a heli field, would provide a tremendous amount of information.
For some who do not know, his device scans the airwaves and provides a visual graph of frequency verses radio frequency power, over a given range.



Finally learned to fly inverted, Helps if you stand on your head

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03-10-2008 07:55 AM  10 years agoPost 52
tadawson

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Lewisville, TX

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My point is that if JR discontinues all their crystal gear they won't have much left....

By the way, I was talking to the Castle folks at a recent trade show regarding 50MHz Berg receiver availability. Lets just say it's a safe bet it's never going to happen. The told me that 72MHz sales are down 80%.
Well, let's see . . . anything that can take a module is compatible with the synth module, so that leaves:

Transmitters:
7207
9303
10X
upcoming 12X

looks like the only one that might be on the fence is the 6102 . . .

Receivers (all synthesized):
R2100 10 chan single conversion
R770 7 channel
RS300 3 channel
RS310 3 channel (this is actually on 27, but still synth . . .)
R2000 10 channel dual conversion
R720UL 8 channel lightweight

So, it looks like the 610, 649, 955 and 945 may go away, but the 945/955 are directly replaced by the 2000/2100, and the 610 by the 720, more or less. The only thing that will be lacking is a 9 channel.

So, once again, I missed something . . . it looks like very little will be unavailable, in terms of capabilities. The only thing still "on the fence" that concerns me is 50MHz stuff . . . it's crystal, but not 72, so I am not sure what their position is on that . . .

Oh, and there is a thead out there that you can convert just about any Berg to 50 by changing one part and the crystal, so despite Castle's apparent decision to whelch on a promise, it looks like Bergs on 50 will still be possible whether they directly build them or not . . .

And as Juggernaut so appropriately stated . . . 72MHz (as well as 50MHz) are licensed bands, which are not subject to every sleazy doohickey that comes floating out of China (or wherever) . . . Myself, I have been flying helis on 50MHz for 6 years now, and never had a hiccup or glitch . . . so basically, I don't fix problems that don't exist! 2.4 would gain me absolutely nothing at this point, other than an expense, and a new set of headaches . . .

- Tim

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03-10-2008 07:08 PM  10 years agoPost 53
JKos

rrProfessor

Redondo Beach, CA

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BTW, there is false information in the Spektrum FAQ item that pH7 gave a link to. Despite what that FAQ says, there is not a requirement for collision avoidance. Frequency Hopping systems do not have to check a channel before transmitting on it.

All of this could be solved mathematically if we knew certain system parameters for all the systems. Unfortunately, I seriously doubt we will ever be given such details.

- John

RR rules!

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03-10-2008 07:21 PM  10 years agoPost 54
Dr.Ben

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Richmond, VA, USA

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I believe no delay, because the Spektrum is only looking to see if some other Spektrum is using the channel. FAAST are basically ignored.
Are you saying unequivocally that ANY other occupation of a channel by a system other than another Spektrum is simply "noise"? If these SS radios are all using the same channel groups, then they must occupy them at one point or another. If FAAST is using those channels, then it must occupy them, if for only a brief interval as hopping occurs. I understand that FAAST only hops for a brief second, but, again, what is the background threshold of MULTIPLE FAAST radios hopping before a Sprektrum sees the channel as occupied?

Ben Minor

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03-10-2008 07:52 PM  10 years agoPost 55
Ron_Osinski

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Russellton, PA

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Maybe I mis-read what you are saying Dr. Ben, but I think you are overlooking bandwidth. Narrowband - FASST 2.4GHz usage vs. the wideband Spektrum 2.4GHz usage. They are not operating the same such as two 72MHz system both on ch. 18.

I don't see a problem with either system conflicting or the traffic that maybe occurring since the GUID each system operates on as well as the "frequency range” within the 2.4 GHz bandwidth keeps each system from responding or even seeing each other. The term NOISE is sometimes mis-used.

Does this make sense? Not trying to make light of it or get into a war.

Spektrum uses 2 unchallenged channels each time you fly. Basically it owns the channels it selects per the ON time of the TX each time you fly once it locks/links and the system connects. This is not to be confused with BINDING. It is a connection between the TX and RX per use/flight. The interesting thing will be if many FASST systems are on at the same time since they hop per their design and will be monitoring the traffic via collision avoidance to not hop on the same channel as another FASST system if the traffic each produces will in fact cause some latency within their own usage. Anyone ever see 20 plus FASST systems on at the same time?

Horizon/JR is NOT getting out of 72MHz systems. The new 12X will be available with 72 RF link. No need to think aggressive radio deals that are being offered are anything hinting that 72 MHz is going away.

Hope this helps. And I look forward to seeing you guys at Toledo in a few weeks too!

____________
Best Regards,

Ron Osinski
aka - GMRO

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03-10-2008 07:52 PM  10 years agoPost 56
Juggernaut

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Canada, Great White North

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any signal from any source other than from the intended transmitter, is considered interference or noise.
The closer or stronger the signal, the more detrimental it becomes, and the more it will interfere or reduce the signal to noise ratio



Finally learned to fly inverted, Helps if you stand on your head

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03-10-2008 07:56 PM  10 years agoPost 57
JKos

rrProfessor

Redondo Beach, CA

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> Narrowband - FASST 2.4GHz usage vs. the wideband Spektrum 2.4GHz
> usage.

FASST actually has a wider bandwidth at 1.6 MHz than Spektrum at 1 MHz.

> Spektrum uses 2 unchallenged channels each time you fly. Basically
> it owns the channels it selects per the ON time of the TX each time
> you fly once it locks/links and the system connects.

The Spektrum system does not "own" the two channels. Other systems are free to operate on the channels at any time.

> The interesting thing will be if many FASST systems are on at the
> same time since they hop per their design and will be monitoring
> the traffic via collision avoidance to not hop on the same channel
> as another FASST system

This is simply not true. They do not employ collision avoidance. None of our RC 2.4 GHz systems employ collision avoidance. FASST tx A has no knowledge of FASST tx B. Airtronics FHSS tx A has no knowledge of Airtronics FHSS tx B.

- John

RR rules!

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03-10-2008 07:57 PM  10 years agoPost 58
DS 8717

rrProfessor

Here wishing i was somewhere else

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And so the answer to the question still remains....... Is Horizon going to discontinue selling systems on 72 ??
No horizon is not going to discontinue 72Mhz,they will be selling the 12X which will be available as both 2.4 and 72mhz.

YOU ONLY LIVE ONCE..IF YOU LIVE IT RIGHT THATS ALL YOU NEED

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03-10-2008 08:52 PM  10 years agoPost 59
Ron_Osinski

rrApprentice

Russellton, PA

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Guess I mis-understood when it was explained to me when I asked very similar questions when I began to fly Spektrum a while back.

"OWN" is a strong term. I likely chose the wrong word. In Spektrum speak my understanding is that once a Spektrum TX is turned on it acquires 2 of the 80 channels in the spread spectrum band to broadcast on. Other Spektrum TX's will not use those same 2 as they acquire 2 different ones...so it owns those per a given on time...my words. That's why only 40 pilots can have TX's on in the Spektrum brand at once.

Thanks Jkos for YOUR clarification on this.

_____________
Best Regards,

Ron Osinski
aka - GMRO

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03-10-2008 09:17 PM  10 years agoPost 60
Four Stroker

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Atlanta

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John's commentary is correct. Many false statements were made when 2.4 GHz first hit the scene (and it's still on the website). Unfortunately, there are many more from diverse sources. For example, the FCC does not allow you to average power over periods when you are not transmitting and there aren't any isotropic antennas.

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HomeAircraftHelicopterMain Discussion › Horizon to discontinue selling JR radio systems on 72 MHz ????
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