RC India

RC Equipments => Radios and Receivers => Topic started by: rcforall on June 17, 2009, 09:17:43 AM



Title: Beginners Radio PITFALLS
Post by: rcforall on June 17, 2009, 09:17:43 AM
Most beginners don't seem to be aware of certain pitfalls when they choose their first radio especially relating to commercial implications relating to frequencies hence I thought it would be a good idea to post  a few points based on my observations for their benefit :

1) I have seen many beginners unwittingly buying  certain frequencies like 36 , 29 , 41 Mhz  radios  just because they get them at low prices  without realising that the problem starts the moment they  want to  add a second Model to their hanger , it is close to impossible  to get reasonably priced receivers for these frequencies , the only option to the buyer is to buy the original receiver of that particular brand  of Radio at exorbitant prices .
Eg : for frequencies such as 35 , 40 or 72 Mhz  you get a wide range of  receivers  around Rs 1000   each  but not so for the rare frequencies .
Hence when you get into your second model you have no option but to buy an original receiver from only a particular dealer  at high prices.

2) Many beginners who choose the 2.4 G route  again face a similar  pitfall  unless they go in for a module based radio eg a DX 6i or a Dx 5 e will be priced around Rs 8 till 13,000 in the first buy but  a receiver alone when you move to the second module will be around Rs 4500 -5000  which is nearly 50 %  of the radio price . You cannot  change to other 2.4G systems such as corona, assan etc and have to use only the original Spektrum/futaba  receivers with their modules .
In my opinion 2.4 G  technology is worth  going in for only in case of Module based Tx which means beyond 7 channel 6 channel 2.4 G technology is too restrictive and expensive. We have had  a couple of major crashes in Chennai with Futab 6 Exa 2.4 G hence reliability is also an issue 


So many beginners I have seem have fallen into this trap of a low priced beginners set up and then being stuck paying for it later.

I thought it important to highlight this as of late I have seen quite a few falling into this trap.

Sai


Title: Re: Beginners Radio PITFALLS
Post by: anwar on June 17, 2009, 11:40:50 AM
Totally true for the first one, and only 50% right on the second one.

I cannot agree at all with the "major crashes and reliability issue with Futaba 6EX 2.4" part.  I would strongly believe that it is user/setup error. 

Moreover, both Futaba and JR/Spektrum 2.4 are much more widely used than Assan, Corona, Airtronics/Sanwa etc, so this just doesn't sound right.

On the web, there are issues and advisories and problematic reviews about them all.  Here is one for Corona http://www.rcmodelreviews.com/coronafhssissues.shtml and one for Futaba http://www.rcmodelreviews.com/futabafasstfoobar.shtml from the same source.  Even within those, it is clear the the Futaba one is a less serious issue affecting only a specific batch of units that can easily be isolated, versus significant design/implementation issues with Corona. And all these issues may have been fixed already (I know the Futaba one is being handled via a recall of the affected units).

So it just makes sense to go with the widely used ones, assuming you have the budget.  Otherwise, they are all pretty similar, and just go with any of the others.


Title: Re: Beginners Radio PITFALLS
Post by: rcforall on June 17, 2009, 11:56:30 AM
Anwar ,
I am talking of beginners here .
I have seen beginners buy 2.4G systems without realizing to start with and then when they get to their second model the fact hits them that they have to spend around Rs 4.5 to 5K for the receiver.
At no point do I say that there are no issues with corona there possibly are , all I am saying is that I know for sure  of 2 major crashes for a beginner with his Futaba 2.4G Chan was witness to both  .

In fact I am of the opinion that for a beginner 2.4 G is not a good way to start , they can start with a reasonable good old proven conventional radio and then graduate to 2.4 as they progress.

Sai


Title: Re: Beginners Radio PITFALLS
Post by: anwar on June 17, 2009, 12:11:19 PM
Like I said, I agree with non-2.4 being a great cost-effective way for beginners to start.  I can see non-big-brand 2.4 radios also being effective for beginners. 

The only issue I have is your highlighting of Futaba 2.4 alone being problematic, which I believe is misleading for people who read this thread.  If your statement also mentioned about other radios possibly having issues, or at least highlighting that it could be due to improper usage, that would put things in the right perspective. We have many Futaba 2.4 systems on our field (from 6 to 14 channels), and I have not seen anything go down purely due to radio issues (of course things go down all the time due to others reasons).


Title: Re: Beginners Radio PITFALLS
Post by: rcforall on June 17, 2009, 12:23:02 PM
any way issues of malfunction apart ,
the Idea of this post was to make newbies aware that there are significant cost factors in terms of receivers when you consider rare frequencies or 2.4 G .
In my business I see so many who have the  :o :o look when they get to the point of the second receiver  not only 2.4 g  but also in the case of rare frequencies like 29 , 36 and 41 mhz .
eg . I had a student who came to me with his 7CAP in 36 mhz which he got from Singapore at a throw away price and was very thrilled with it till he wanted to get into his second Model , then he could not find the receiver any where in India and when he got back to Singapore asking for the receiver he was  given a price which nearly cost him an arm and a leg he nearly gave up aero modeling due to that .
Another relates to 29 Mhz where  a person took 6-8 months to be able to lay his hand on  a second receiver with a matched crystal this was also  available only at Singapore.

It  better to be informed about the costs at the begining rather than be  :o ??? later , I am sure there will be many who take the decision despite knowing and rightly so which is OK.
sai


Title: Re: Beginners Radio PITFALLS
Post by: anwar on June 17, 2009, 12:29:40 PM
Yes, receiver cost is something to be seriously considered during selection of radios, especially for beginners on a budget. Point well made.


Title: Re: Beginners Radio PITFALLS
Post by: chanvivek on June 17, 2009, 01:05:24 PM
Hi there,

I agree that I was witness to both the tragedies of a Futaba 6EX 2.4Ghz system.  But the following points are to be noted,

1. The temperature was very high both the times.
2. Both planes were trainers and the Rx had no ventilation / cooling.  Unlike FM receivers, 2.4 Rx are very prone to heating!! So if it heats up a lot, then it would drop range / functionality!! So it is adviced to mount a 2.4 Rx on its side and not on its base to have more surface exposed to air for better cooling!!  Moreover, the Rx was wrapped in foam both times and so no place for heat dissipation.  These 2.4 Rxs are not at all sensitive to vibrations unlike FM Rxs.  They dont need foam padding.  just a double side tape would protect it!! Courtesy : 2.4gigahertz.com FAQs!!
3. The Rx voltage is very critical while going for 2.4 systems.  I generally do not trust my 2.4s with a Ni-Cd.  I always use Lipos with BECs.  So both crashes might also be becuase of a low voltage reset which is quite common because 2.4s draw a lot of voltage!!
4. Both times, the crash was on the 2nd sortie.  The first sortie being atleast 20 mins.  Again a question of low Rx power.  The first sortie might have drained it out.
5. The same Rx was used during both crashes.  Might be because of a faulty Rx.
6. Finally, for beginners, 2.4 is quite tough, taking into consideration the cost (primarily) and the responsibility!! If someone can handle both, then 2.4 is the way to go!! I have been flying 2.4 for almost a year!! Dad had his 2.4 Futaba 6EX for almost 2 years!! Never a problem, never a glitch on both the Spektrum Dx6i or the Futaba 6EX!!

But also, if a beginner chooses a regular radio (say Futaba Skysport 4 channel FM), then lets say in about 3 months, he might need a programmable radio.. Then change to a 6 channel computerized!! After another 5 to 6 months, might need more programming options.. again upgrade!! 10 channels!! So finally, the cost is the same! The time frame is different thats all!! So I would always advice people to buy the best radio they can afford always because it would definitely not be a waste of money.. They are going to use it sometime or the other!! My personal experience!!  My radio lineups!!

1. Hitec SS Neon FM - 3 channels
2. Hobbico FM - 3 channels
3. Futaba Skysport FM - 4 channel
4. Turborix FM - 6 channels
5. Futaba 6EX 2.4 - 6 channels computerized
6. Spektrum DX6i 2.4 - 6 channels computerized
7. Futaba 10CHG 2.4 - 10 channels computerized

If I had bought the 10 Channel earlier, I would have definitely saved a lot of money invested on the first 6 radios!!  Now I fly only 2.4 and dont have a single FM Rx that I would trust on a plane!!

There are people who swear by 2.4 and there are people who swear by FM!! I am of the former category!!

Specially in a field dominated by 72 Mhz, I think I would have a much much more free mind set flying rather than worrying about interferences.  Even when there is a crash, we tend to blame people who are on the same frequency though it would have been a pilot error!! Now with 2.4, all this confusion can be avoided...

The only drawback about 2.4 systems is the PRICE!! I still cry to pay 5k for a regular 7 channel Rx!! My model would be a scratch built foamy for about 200 Rs!! But the Rx on it would be a 5k Rx!!  A module based Tx might just be the solution.. FM for cheaper planes and 2.4 for bigger ones!! I deliberately did not want the module based 10C mainly because of the ergonomics!! The ugly 2.4 antenna sticking behind the handle is a real ugly sight!!  And moreover, I dont have 72 Rxs to use though I have some 2.4 Rxs now!!

My 2 cents!!

I also totally agree with the Rx cost!! But for me, even though I crib about the price, I buy 2.4 Rxs because I get my peace of mind!!


- Chan


Title: Re: Beginners Radio PITFALLS
Post by: anwar on June 17, 2009, 01:31:41 PM
Yes, it is also important to consider why 2.4 technology was invented.  If you fly in a field with many others (especially people coming and going) on non 2.4Ghz, there are significant possibilies of getting your craft shot down when someone else turns on their radio at the same time on the same channel.

Not having to worry about this is something I personally preferred over any percieved reliability issues of 2.4.  In fact, other than the flyer "dumb-thumbing", I have seen more aircrafts smooch the ground due to two people getting on the same frequency (and after that, taking off with the wrong model selected in the radio is the most common reason).  This is exactly why 2.4 came in to existance, and is becoming so widely accepted that it is on the way to totally eliminating non-2.4 (except for rare situations like pylon racers with full carbon fibre fuselages, which have issues with signal attenuation on 2.4Ghz).


Title: Re: Beginners Radio PITFALLS
Post by: rcforall on June 17, 2009, 02:12:14 PM
Hi Guys let us discuss the merits and demerits of 2,4 G etc on another thread . >:(
As much as you guys are 2.4 g fans I am a 2.4 g Skeptic  in fact in 5 years of flying I have seen a freq. clash shooting down a plane just once and heard of another.
The intention of this thread is Info for beginners  Its not a thread on 2.4G.
It is thread on beginners radios issue
observed by me as a seller


Title: Re: Beginners Radio PITFALLS
Post by: anwar on June 17, 2009, 02:17:09 PM
Sure !  Except that your initial mention of "reliability" is part of "merits and demerits". 

The only reason I pitched in is because I felt people (especially beginners) would be misled about "reliability of one brand" of 2.4 with your initial post, and that is not fair.  If it was a cost only discussion, I would keep quiet  ;D

Plus, any discussion which dwells on the positives is good discussion !!! :)


Title: Re: Beginners Radio PITFALLS
Post by: chanvivek on June 17, 2009, 02:21:43 PM
sorry!!  ;D ;D just coudnt resist defending one of my favourite technology in aeromodelling ;D  ;D  ;)!!

- Chan


Title: Re: Beginners Radio PITFALLS
Post by: anwar on June 17, 2009, 04:11:16 PM
 8-)  8-)  8-) Chan  ;D

Even if we look at Sai's experience, he has seen two cases of frequency conflict crashes (which can be confirmed to some degree) and two cases of 2.4 crashes (which are tougher to establish, based on Chan's comments). If that is the only information I had on the subject, I would still lean towards for 2.4 (and not live under the constant fear of getting shot down by someone else on the same frequency, not to mention having to ask everyone/newcomers around before taking off).


Title: Re: Beginners Radio PITFALLS
Post by: rcforall on June 17, 2009, 04:18:26 PM
2 of shot down by freq in 5 years and  2 by 2.4 in 3 months that is the diff ;D ;D ;D
so by law of averages yearly crash ratio is 2/5 per year for good old faithful and 8 per year for 2.4 g . I believe in maths .
So Good old freq  {:)} {:)} {:)} {:)}

BTW Guys I am a Janta class Modeler  not a High fly deep pocket Modeler , My planes all cost not more than  a few hundred bucks average  not couple of Thousand Dollars  so as Chan himself says I don't have to put  a 5 K receiver on a Rs 200 plane . So this post is not for the rich kids on the block :D ;)

sai


Title: Re: Beginners Radio PITFALLS
Post by: anwar on June 17, 2009, 04:22:46 PM
You win  ;D ;D ;D

Wait ! Let me do the same math !  Two pylon racers crashed possibly due to 2.4 in the past one year.  About 9 crashes due to frequency clashes in the past two years.  Hmmmmmmm.............. ;D

If you want to get the real tally of frequency conflicts, we need others also to comment who fly in a crowded field  ;)

And I thought you were selling affordable 2.4 systems, and your initial post was about them ;D

Can everyone who has already not done so vote in the transmitter polls ?

http://www.rcindia.org/radios-and-receivers/the-radio-transmitter-polls/


Title: Re: Beginners Radio PITFALLS
Post by: chanvivek on June 17, 2009, 04:39:34 PM
I don't have to put  a 5 K receiver on a Rs 200 plane . So this post is not for the rich kids on the block :D ;)

sai

100% true!! Thats infact pathetic that we have to put a 5k Rx on a 200 Rs plane!! But what choice do I have??? And the worst thing is, I dont want to be blamed for any frequency clashes on the field!! Chennai flyers would know how it is here!! So I went 2.4!!And I dont even carry a FM radio there!! Once, more than a month back, there was a crash and I was questioned whether I had any FM radio with me though everyone knows that I fly only on 2.4!! They wanted to know whether I was carrying any old radio with me!! And believe me, there are instances when people claim that 2.4 systems interfere with each other and again I was questioned!!  If you dont believe me, check my post on this thread,

http://www.indiarc.com/forum/index.php?topic=2450.15

Moreover, I generally keep one Rx for foamies, and I switch that Rx between them.. I dont have more than 3 Rxs though I have numerous planes!!  And I never take more than 2 models to the field.. So no probs!!

And finally... I am going to be shot here by Mr. Sai for repeatedly hijacking this thread!! Anwar... high time we start trolling someone else's thread  ;D  ;D  ;D!!

- Chan


Title: Re: Beginners Radio PITFALLS
Post by: izmile on June 17, 2009, 04:58:26 PM
Specially in a field dominated by 72 Mhz, I think I would have a much much more free mind set flying rather than worrying about interferences.  Even when there is a crash, we tend to blame people who are on the same frequency though it would have been a pilot error!! Now with 2.4, all this confusion can be avoided...

Yea.. blame it on the technology!.. :D


Title: Re: Beginners Radio PITFALLS
Post by: chanvivek on June 17, 2009, 05:00:52 PM
 ;D  ;D  ;D


Title: Re: Beginners Radio PITFALLS
Post by: Pikle6 on June 18, 2009, 06:05:28 AM
he guys  am sending all of you a coool glass of lemonade drink that take  a deep breath and relax.

i have 72 mhz system which i have never used in a crowded area and now one thing what i want is a good radio with a lot of programming available and possibly around 15k and good quality. and i love new technology.


airtronics rds 8000

airtronics - quality assured
rds8000- all programming available.
cost 13 k with 4 servo's rx rx bat tx bat tx switch harness, wall charger.

still if anyone can give me a better system or same in 72 mhz with the same price i am in i will buy it.

also the v22 will be exhibited in crowded area i dont want to have the audience to be put off due to the reasons which i dont need to mention.

sorry chan bhaiya let me copy your line.

my three cents (as i dont want to use two you might kick me out of here)

subbu






Title: Re: Beginners Radio PITFALLS
Post by: rcforall on June 18, 2009, 08:34:37 AM
The purpose of this thread was precisely this that a new buyer be aware of the costs involved in going either way. It has at least got Subu thinking on the cost benefit of either option before deciding hence the desicion will be more suited to him.

For me the 2.4 G route will be too expensive as I largely do scratch building and experiment with planes hence I have around 6-8 receivers which I use , I don't normally keep switching receivers between models each of my work horse models has its own receiver hence I found the conventional 72 mhz type system to be more cost effective .Hence if you are going to be this type of modeler then the FM radio route may be more economical.


Sai


Title: Re: Beginners Radio PITFALLS
Post by: FlyJoe on July 11, 2009, 01:38:30 PM
My 2 cents - considering that this is about radio pit falls for beginners -
I think the biggest pit fall for beginners is the lack of education coupled with lack of common sense ;)
When i was going to get a radio I did some reading and some math. I had a choice of picking up a 6 channel FM with a couple of RXs and spare crystals and also the 2.4 with 2 Rxs.
When I worked the math the 2.4 was more costly but I realized with the right education on the uses and common sense regarding the fine tuning and possible glitches. I can enjoy the 2.4 technology and also avoid an upgrade in the future.
At the same time my friend next door went in for the FM and he too read and learnt about the boundaries and Uses... He's happy too. He has a High winger and a low winger, flies 4 times a year only! (something like summer, winter, autumn and spring) ;D
So its not so much the rich boy and the poor boy (couldn't help that ;D) coz at the end of the day it's not the money coz i know at least 3 people on this forum who carefully collected money to buy their radios. which would be the case whether it was FM or SPREAD.
The pit fall is the Hurry syndrome. if a person takes time to see what the difference is and what his need is and what his budget is and ultimately the difference between Hobby or Fever.
Hobby is terminal :D but fever has a pill called 'interest drain'
This is the biggest killer, coz if its not a passion then all goes to waste FM or 2.4 = 0.0


Title: Re: Beginners Radio PITFALLS
Post by: tg on July 12, 2009, 10:40:26 AM
Nice analysis, fever (draining interest) = resale at a lower price  ;)