Why FM radios (72Mhz etc) are not a good idea any more ?

Started by anwar, August 04, 2009, 05:20:18 PM

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atul_pg

wow you guys are good  ;D I wish i had tat kind of skill while arguing with my wife  ;D   ;D

am not sure if i will make sense but here goes..

as a beginner i would prefer to go in for a mhz tx since the rx cost is less and besides a person like me who doesnt get to fly except on sundays would rather invest less or invest where its required as of now..besides i dont want to get hurt if i lost a rx worth 5000/-rs over a plane worth 4k or 5k as per a beginners plane..

2.4ghz is no doubt the future & no arguments abt tat, i have used it personally and it's superb...but mr.sai is rite why waste a lot of money when u can get some hack modules & transform your older tx to a 2.4ghz plus the rx cost would be less to original 2.4 available tx..

this is just my view.. cheers..

anwar

Again, misconceptions.  Cost for 2.4 is not really that big an issue with Assan, Corona etc. Even the simple coax helis (like Lamas) are beginning to ship with 2.4 these days.  Just look at HobbiCity for cheap 2.4 stuff.

But the issue is different.  The reason I started this thread is because people are nit-picking remote possibilities of problems with 2.4, while conveniently ignoring (or being silent about) similar and much more serious issues in the Mhz bands.  The biggest problem is that they get passionate about 2.4 issues that are far fetched (and rare), while ignoring "every day" issues in the Mhz side.  How unfair ? ;)

So let us continue nitpicking Mhz stuff for more fun....
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rcforall

#27
Tally ho !!!!!
Anwar go ahead and consolidate your list again I will love it .

But  the simple fact is that it makes sense to buy a Mhz radio and convert it to 2.4 .
Even in the case of a Module based Tx  buy a Mhz radio and also buy a Assan or Corona module and switch modules and enjoy the best of both worlds ;D ;D

BTW the Mhz Radios are cheaper  now a days as well that is the icing on the cake

sai
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sahilkit

1.frequency conflicts can be avoided by having a frequency scanner in the TX like the multiplex has  
2.transmit the data on two different frequencies/ two receivers  
3.frequency monitor system in the receiver itself with fail safe features
4.GPS unit along with receiver with home option auto pilot landing  8-)

these should solve most of your problems and make HF/VHF bands more safe or equal to 2.4GHZ

to make it short one can implement the 2.4GHZ features on HF/VHF bands

sahil
Today might be a great and wonderful day. It depends on you.

sahilkit

opp sorry did not see the heading,I'm suppose to bang the 72mhz etc bands. I personally prefer HF/VHF bands but u guys have to remember that first all the RC bands are not legal in India or rather used for some other purpose hence we see lots of interference on the bands. I think once we organize and set standards then we will be able to reduce number of problems.

sahil
Today might be a great and wonderful day. It depends on you.

Pikle6

just ten minutes earlier i went to taxi my e-starter in the parking lot after plugging in battery the motor went at 3/4 throttle and rudder deflected to the left. i think it caught up a very very very strong interference indeed though i taxied my e-starter many time with 2.4 as its batt was down i took my 72 mhz.

i taxied as flying was not allowed i think govt ban policy has something to do with this


subbu

(i was nearly scared to death as the plane was facing me and behind me was a sparkling car)
E.V.Subramanian
Yak55|EasyFly Glider 1.9m|Skyfun|Easystar II|Quad Talon V2|Mini Saturn

rcforall

The Spare Assan Module I mentioned about earlier has been booked by Saurabh.

So two 72/2.4 G transmitters on the way .
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rcforall

#32
Since Anwar is not doing it here are the limitations of Mhz Radio's :

1. Anyone can cause your model to crash by turning on their radio on the same channel, either by mistake or intentionally.  That is a truly uneasy feeling, which one has to suffer through every time you go flying, especially in places where many people fly together.

2. Forgetting to extend the antenna before take off results in loss of control.

3 PPM communication is susceptible to static build-ups, especially in the case of electric helis with rotating belts

4 72Mhz etc communication is susceptible to ignition noise on gas engines  ???

5 PCM, which is the more widely used one, is known to mask interferences/glitches up to a certain level, causing small problems to go un-noticed initially.  Finally, after crossing a threshold, the glitches surface in its full force, causing loss of control/communication ("PCM lockouts") for possibly up to many seconds.

6 Interference from non RC transmissions on the same band .

Sai

PS> Anwar add some more if I have missed out any no problem ( feel  :( to see you so quite on this thread started by you to bash Mhz Radio's ) but think of the future you will also be bashing " FUTABA " as the most popular  these radio's is the  6exa futaba
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izmile

Quote from: rcforall on August 05, 2009, 11:06:55 AM
4 72Mhz etc communication is susceptible to ignition noise on gas engines  ???

I am bit skeptical on that. If you have an AM radio - no matter what freq - you will have intereference due to spark produced by the spark plug. The arc created by the spark plug intereferes with the amplitude of the signal that you transmit. It does NOT corrupt the frequency. Having said that, if you have a FM radio you will not have interefernce from the spark plug, unless your receiver is way too close to the spark plug.

As an experiment try this... take a pocket radio or desktop radio and turn it ON in your car... Note that the antenna of the radio should be close to the dashboard... better open the boot of your car and try it closer to the engine. Tune the radio to an MW or SW station (thatz AM)... now when you run your car (just idle it no need to drive) you can hear a rythmnic noise that is synchronized to your accelerator pedal... more acceleration more denser the nose rythmn. Thatz due to the increase in sparking freq as you accelerate... Now, tune to an FM channel.. do the same steps before.. you would notice the noise is considerably lesser.. And at about 1 or 2 feet distance from the engine you would never hear a glitch!.

-Ismail
"Anything can fly" - SPADs just prove that!

rcdhamaka

All leading radio brands like Airtronics/JR/Futaba/Hitec will be discontinue FM radios very shortly most of their models are discontinued. Hence the service and support for this will also go. This another very big reason FM radios are not a good idea anymore.
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rcforall

Quote from: rcdhamaka on August 05, 2009, 12:38:21 PM
All leading radio brands like Airtronics/JR/Futaba/Hitec will be discontinue FM radios very shortly most of their models are discontinued. Hence the service and support for this will also go. This another very big reason FM radios are not a good idea anymore.

Do we get service in India for most of these brands in any case 2.4G or FM  ???

Are you offering warranty as part of the support and service ? If yes  {:)}

Don't see it mentioned  in the item.

Sai

www.zuppa.io : vehicle telematics, ADAS, IoT , Drones

anwar

If there is a serious enough problem (I remember the wire chaffing issue on JR XP9303s), you always have the option of sending it to the US, Taiwan, Japan etc, if there is warranty support. 

Even that option goes away if the entire product line is discontinued (which, I don't see happening any time soon).  But the manufacturers have sort of stopped developing new products in the Mhz range, which is a sign of things to come (whenever that is). 

Would you buy an Ambassador car now ? :P   <=== I congratulated myself 3 times for coming up with this.  This sure will make Sai mad ;D ;D
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rcdhamaka

Dear Mr. Sai,

I do not know if you are aware that for any futaba warranty or service you need to send it to Singapore.

Yes warranty is applicable on manufacturing defects the customers needs to bear shipping costs. All are radios come in from the manufacturer and carry the warranty as per manufacturer. You need to send it to manufacturers authorised service centre.

But when they stop production or discontinue a product then after a year from them discontinuing that product they are not liable to give you support or service on the same.

We are not against any technology but when a particular product is discontinued then it will not make any sense in buying it. Also we are not here to argue for the sake of arguing or adding more number of posts. But facts are facts. Every technology has a life span, even 2.4ghz will be overshadowed by newer technology in the future. But for now 2.4Ghz is the future.

All advanced aspects like software, triple rates,etc will now only come out in 2.4Ghz
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rcforall

Strictly my opinion .

I don't see the Mhz range disappear altogether mainly because it is widely used in FPV and UAV applications where using a 2.4 G radio is not possible as all these systems are designed on either 2.4 G or 1.3G or 900 Mhz  ( long range )
Like this http://www.rangevideo.com/index.php?main_page=index&cPath=35_22

This is becoming quite popular in the west hence if this trend gets stronger then this niche market will be good money for any manufacturer who also manufacturers Mhz radios.

Sai
www.zuppa.io : vehicle telematics, ADAS, IoT , Drones

rcdhamaka

#39
Also people who do not know:

Here are some links:
http://www.jrradios.com/Products/Radios-Air.aspx
Here in the air & helis section you'll can clearly see that there are no FM radios in their line up

Spektrum:
Only sells 2.4Ghz radios

Futaba someone has already posted the discontinued list earlier and you can see from their present line up FM radios they have hardly a couple of them in FM.

http://www.airtronics.net/
Here you will see that they have discontinued their Classic range that is the FM radios.

Hitec will shortly update their site on it once they have launched their 2.4Ghz radios.

Authorised Distributors in India for: JR - Japan, Multiplex Germany,  ALIGN, Xoar USA, Extreme Flight RC, 3DHS, Krill Model Aircraft, Desert Aircraft, Secraft, Sebart, KingTech, GoldWing, EG Aircrafts, ASP, Sanwa Japan, Phoenix Models, Great Power Engines, Saito Japan, EMAX, YINYAN, Flightline, and many more
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rcforall

#40
Quote from: anwar on August 05, 2009, 01:04:07 PM

Would you buy an Ambassador car now ? :P   <=== I congratulated myself 3 times for coming up with this.  This sure will make Sai mad ;D ;D

Sure  would if I can convert into a Ferrari at half the price  ;D ;D ;D and continue to operate it  at the cost of an Ambassador  and not a ferrari :P ;D ;D <=========  time to rake your brains for a better come back
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sandeepm

Quote from: rcforall on August 05, 2009, 10:59:20 AM
The Spare Assan Module I mentioned about earlier has been booked by Saurabh.

So two 72/2.4 G transmitters on the way .

Mr. Sai,
What is the cost of this assan set?
Fly high if you have good set of batteries.....!

rcforall

Quote from: sandeepm on August 05, 2009, 01:27:40 PM
Quote from: rcforall on August 05, 2009, 10:59:20 AM
The Spare Assan Module I mentioned about earlier has been booked by Saurabh.

So two 72/2.4 G transmitters on the way .

Mr. Sai,
What is the cost of this assan set?

Will PM you tomorrow.

sai
www.zuppa.io : vehicle telematics, ADAS, IoT , Drones

anwar

Quote from: rcforall on August 05, 2009, 01:17:25 PM
Sure  would if I can convert into a Ferrari at half the price  ;D ;D ;D and continue to operate it  at the cost of an Ambassador  and not a ferrari :P ;D ;D <=========  time to rake your brains for a better come back

But why, when you can buy the Ferrari itself (a Suzuki Swift would be a better/realistic analogy) !  No matter how much you convert and mess with it (which by the way, costs half the price of a Ferrari and the skills required to do it) you end up with something that everyone jokes about, and with no spares ;D
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anwar

Quote from: rcforall on August 05, 2009, 01:13:24 PM
Strictly my opinion .

I don't see the Mhz range disappear altogether mainly because it is widely used in FPV and UAV applications...

This is becoming quite popular in the west hence if this trend gets stronger then this niche market...

Sai

Good to see you finally admitting that Mhz is becoming a niche application thing ;D 
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anwar

Quote from: izmile on August 05, 2009, 12:07:02 PM
I am bit skeptical on that. If you have an AM radio - no matter what freq - you will have intereference due to spark produced by the spark plug. The arc created by the spark plug intereferes with the amplitude of the signal that you transmit. It does NOT corrupt the frequency. Having said that, if you have a FM radio you will not have interefernce from the spark plug, unless your receiver is way too close to the spark plug.
-Ismail

That is an AM versus FM comparison.  My understanding is that the Ghz range is more resilient to ignition noise as compared to the Mhz range.  Would love to hear your comments on this.

PS: I left the circuits world a long time ago, and that too even before getting into it too seriously.  I currently live in the world that makes things like these forums possible.
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rcforall

Quote from: anwar on August 05, 2009, 01:38:57 PM
you end up with something that everyone jokes about ;D

Frankly never been bothered by what others say ever . I have the confidence to execute new concepts
I go where others fear to tread and create a path for others to follow.
 

Come on Anwar I expected better come back's from you  :P  ;D ( no hard feelings )

sai
www.zuppa.io : vehicle telematics, ADAS, IoT , Drones

rcforall

Quote from: anwar on August 05, 2009, 01:42:20 PM
Good to see you finally admitting that Mhz is becoming a niche application thing ;D  


Never had an issue with that in fact  from my experience in marketing Niche markets are great places to operate in .

I would love to be the only seller of Mhz Radio's  in India. Can you imagine it from a business point of view .
But not all can be niche marketeers that requires creativity

sai
www.zuppa.io : vehicle telematics, ADAS, IoT , Drones

anwar

Quote from: rcforall on August 05, 2009, 02:03:42 PM
I would love to be the only seller of Mhz Radio's  in India.
sai

You are again admitting that Mhz is becoming non-mainstream (i.e. niche only) ;D 

Come on...  you can do it. Just say it aloud...  "Mhz is dying, everyone who is getting a new radio better go for 2.4Ghz"... ;D ;D

Just take a deep breath and repeat after me..  it is not as tough as you think it is .... :P :P

PS: My father is wondering why I am sitting in front of the computer and laughing hysterically ;D
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rcforall

I repeat it  as below :

"  Start
BUY  A MHZ RADIO ITS CHEAPER BUY A 2.4 G MODULE LIKE ASSAN OR CORONA  CONVERT THE MHZ RADIO TO 2.4 G USING THESE MODULES  AND ENJOY THE BEST OF BOTH MHZ AND 2.4 G RADIOS AT HALF THE PRICE ""
{:)}

why get stuck with an original 2.4 g radio and keep paying high receiver prices when you can get it cheaper .

I have said it before and say it again I am not against 2.4 G but I will adopt it the way that appeals to me best .
And if I know of something good I will share it with guys here


Kindle the creative side of you.

Don't follow the beaten path.

Sai

PS Anwar  once again {:)} {:)} {:)} {:)}  this sort of fun could not be possible at the neighbour  without all of us getting banned
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