Beginner questions about radios

[paul devereux]

On 22/02/2023 at 05:25, Graham Bowers said:

“Best” is a very subjective word, depending on expectations.

 

What, from a user experience perspective, do you think you want? Or put another way, what problem, present or anticipated, do you wish to solve by changing your Tx?

 

If you don't know that, then in my opinion there's a distinct possibility the replacement may be better, or may be worse.

 

I used   a Multiplex MC4000  for some years then changed to open source radios (Taranis and Radiomaster)  as OpenTx seems to pretty much copy the functionality of the MC4000 firmware, where you have pretty much complete freedom. I only changed to the Taranis for it's telemetry  functionality. If you want to know what the capability of OpenTx is and what it does, here's a good place to start http://rcdiy.ca/opentx-guide/

 

I recently bought a Multiplex Cockpit SX 9 and just can't get off with it so it will be sold. It's a beautiful thing, well made, and I've tried so hard to love it. However it's a shadow of the MC4000 and it's functionality is limited to what the firmware menus allow. A clincher is the countdown timer. If you want to have a countdown timer, you are forced to accept one minute reminders for the last 5 mins of your flight. And it doesn't sit well in my hands.

 

Other than that, I concur with @GrumpyGnome. And you have to hold these things in your hands or take a risk.

I think I got a bit over-excited at learning how to use a computer radio! I've got it now: separate model memories, count down timer, dual rates and expo, end-points, assigning switches. Now I just have to learn to fly!

Edited February 27, 2023 by paul devereux

[leccyflyer]

As regards which switch to use for which rates, the older Spektrum DX7, which I still use for a few models with DSM receivers, have the switches explicitly named, elevator rates on top left, aileron rates on top right. So on my DX9 I've followed the same convention and ported the same over to my venerable FF9, since it seemed sensible to keep the same basic configuration on my three transmitters in use. The same for my retract switch, first long switch on the front left hand side of the transmitter.

 

[paul devereux]

43 minutes ago, leccyflyer said:

As regards which switch to use for which rates, the older Spektrum DX7, which I still use for a few models with DSM receivers, have the switches explicitly named, elevator rates on top left, aileron rates on top right. So on my DX9 I've followed the same convention and ported the same over to my venerable FF9, since it seemed sensible to keep the same basic configuration on my three transmitters in use. The same for my retract switch, first long switch on the front left hand side of the transmitter.

 

Thanks, yes it is all starting to make sense. My father had a RC plane, one channel (I think he called it bang bang but I might be mistaken). Then he had an Acoms two channel radio (two sticks, elevator left, rudder right, both proportional, which was the bee's knees 60 years ago). Then he gave up RC. My Futaba has default aileron right, elevator left D/Rs. 

My father would never have dreamed of the way modern radios work.

Edited February 27, 2023 by paul devereux

[kc]

Earlier in this discussion someone mentioned that Spektrum has Model Match ( meaning that particular model memory is bound to a certain Rx )  but not all makes have that facility.    The last time I asked about this it seemed that Futaba does not have any 'model match' function.   That means that my  Futaba FAAST 6EX 2.4 can be set on the wrong model memory which might have reversed servos or different movements etc.    So not checking the model memory is right for the model could be a disaster!   Obviously important thing to check every flight.  

 

I dont know if Futaba have installed any form of model match in their newer systems.  Also nobody mentioned whether any of the other new makes like Radiomaster, FRSky have any form of model match.   Perhaps someone could clarify which systems have a model match facility and which do not?

 

[Capt Kremen]

Radiomaster Rx can be assigned a number, as can Multiplex Rx too which is then associated with the specific model that Rx is installed in.

If you remove and install that Rx in a.n.other model the association/link continues unless otherwise re-numbered and of course any model specific changes are made.

[GrumpyGnome]

The mpm in the Radiomaster seems to assign a number to any receiver it binds to so you get peace of mind on most receivers...... voice alert is also useful in calling out the model name when you select it/turn on the Tx.  And you can have a pretty picture too.... 

 

[Peter Jenkins]

I'm with those who use the Flight Mode switch method.  All three rates are worked by one switch as also are my throttle curves.  So my Flight Modes are Spin, Land, Aero or normal flying.  I also use an idle switch - for electrics it gives the lowest speed the motor will run at and for IC it will drop to the lowest speed the engine will run at.  For electrics I select no idle for flying and idle for landing and for IC I select high idle for flying and lowest idle for landing.

 

So basically 2 switches for sorting everything out on the model.  I use separate switches for any special mixes e.g. a downline mix to give a smidge of down elevator with fully closed throttle for a vertical downline.

[paul devereux]

11 hours ago, kc said:

Earlier in this discussion someone mentioned that Spektrum has Model Match ( meaning that particular model memory is bound to a certain Rx )  but not all makes have that facility.   

 

This has added a new dimension and dilemma to learning about computer radios. Suppose I have a Futaba 7c (I have). I set up memory for two models ( I have a Wot4 Foam E and a Multiplex Merlin, the Wot4 has the Futaba RX and the Merlin a clone). Then I swap the RXs (because the Futaba Rx is small enough to fit the Merlin, and I put the Orange clone into the Wot 4. Does the model memory for trim, dual rates, etc, still exist for the two models, or do they both have to be set up from scratch again?

[Peter Jenkins]

Putting it simply the Tx has the model memory details.  These details can only be changed in the Tx when that memory is selected and has nothing to do with which Rx is being used.  For a Tx and Rx to work (for 2.4 GHz radio) the Rx must be bound to the Tx.  The Rx will do as its told once it has been bound.  If the radio has a model match facility then not only does the Tx and Rx bind but the Rx is bound to the specific Model Memory in use while binding.  If the radio doesn't have model match then provided the Rx has been bound to the Tx it will accept the information from any model memory.  It is up to the pilot to pick the correct model memory to match the model being flown.  This means that you will be able to fly a model with the wrong model memory selected - this could be either disastrous or make no difference at all if the model memories have identical settings - usually though, they settings are different e.g. elevator going in the opposite direction!

[kc]

You need to be very careful of electric models with any Tx that does not have model match.   If you leave the Lipo plugged in on an electric model and then start another model then the electric model also starts up when you open the throttle!    Both models react!    All models on that Tx  are bound to the same Tx and react if they are still powered up.    Just something to beware of and take proper precautions.

 

Paul, if like me you are a Mode 1 pilot ( throttle right ) yet fly with mostly Mode 2 pilots you need to be particularly careful that nobody else picks up your Tx without realising the throttle is on the opposite side to that expected!   Especially with electric models.    Again something to be careful about, not a problem.  

 

 

[Outrunner]

1 hour ago, kc said:

You need to be very careful of electric models with any Tx that does not have model match.   If you leave the Lipo plugged in on an electric model and then start another model then the electric model also starts up when you open the throttle!    Both models react!    All models on that Tx  are bound to the same Tx and react if they are still powered up.    Just something to beware of and take proper precautions.

 

Paul, if like me you are a Mode 1 pilot ( throttle right ) yet fly with mostly Mode 2 pilots you need to be particularly careful that nobody else picks up your Tx without realising the throttle is on the opposite side to that expected!   Especially with electric models.    Again something to be careful about, not a problem.  

 

 

 

Why would you ever leave a battery plugged in on a electric model! Model match or not a battery should never, ever be left plugged in except when flying.

 

Nobody should ever touch another pilots Tx unless invited, even if they did there should not be an armed model sitting around waiting to accidentally start.

 

 

 

 

[kc]

You are right of course but mistakes do happen.   Actually it is common to hand a Tx over to a clubmate when collecting the model and that's when it's important to remember some people have the throttle on the other side.

[Peter Jenkins]

There is a perfectly sound reason not to hand a 2.4 GHz Tx to a Clhbmate especially when fealing with an electric aircraft. Best to keep it with you and use a throttle kill switch.

[leccyflyer]

Indeed - I've never understood the practice of putting one's transmitter on the ground, or handing it to someone else when retrieving a model. You're still the pilot in charge of that model until you have rendered it completely safe -in the case of an electric model by disconnecting the power source - and you should have hold of the transmitter until then.

[PeterF]

17 hours ago, paul devereux said:

This has added a new dimension and dilemma to learning about computer radios. Suppose I have a Futaba 7c (I have). I set up memory for two models ( I have a Wot4 Foam E and a Multiplex Merlin, the Wot4 has the Futaba RX and the Merlin a clone). Then I swap the RXs (because the Futaba Rx is small enough to fit the Merlin, and I put the Orange clone into the Wot 4. Does the model memory for trim, dual rates, etc, still exist for the two models, or do they both have to be set up from scratch again?

The one setting that is recorded by the Rx is the failsafe positions in case you loose radio signal. Most equipment can do failsafe and must be set. If you then swap RXs between models you must teach the RX the failsafe settings for the new model. Consider, especially IC where one model might have the throttle servo reversed but the other not reversed. Swapping the RXs around without resetting both failsafes would mean both models would go to full throttle on loss of signal.

[Geoff S]

2 hours ago, leccyflyer said:

Indeed - I've never understood the practice of putting one's transmitter on the ground, or handing it to someone else when retrieving a model. You're still the pilot in charge of that model until you have rendered it completely safe -in the case of an electric model by disconnecting the power source - and you should have hold of the transmitter until then.

 

I agree, now we have 2.4gHz communication with receivers bound to its transmitter but in the days of 35Mhz there was the potential for your transmitter being nearer to someonelse's model than its pilot's and cause interference. At least that was the theory and the reason for leaving it in the pilot box. 

[Peter Jenkins]

Good point Peter.

 

The other pojnt is that if the radio equipment has a Failsafe facility it must be set.  All 2.4 GHz radio has a failsafe facility and most 35 MHz radio does.  If I remember correctly, all Dual Conversion Rxs have a failsafe.

[GrumpyGnome]

If my transmitter is switched on, it never leaves me.....

[leccyflyer]

54 minutes ago, Geoff S said:

 

I agree, now we have 2.4gHz communication with receivers bound to its transmitter but in the days of 35Mhz there was the potential for your transmitter being nearer to someonelse's model than its pilot's and cause interference. At least that was the theory and the reason for leaving it in the pilot box. 

True, and at the time we were all on 35mhz that might have been considered best practice. Though there are still some flyers using 35mhz these days, they are mostly in the minority.

[john stones 1 - Moderator]

Not a great deal wrong with a clubmate who's not an idiot holding your TX whilst you retrive a model, after all you could trip, knock up the throttle, models takes off downs an airliner, which crashes into a school causing a fire which engulfs a City and thousands die, Putins granny is in the city, he's miffed so launches intercontinental missles on Donny, our fields out of use now coz it's radioactive n I've paid £55 for nowt. 😥

[paul devereux]

6 hours ago, leccyflyer said:

Indeed - I've never understood the practice of putting one's transmitter on the ground, or handing it to someone else when retrieving a model. You're still the pilot in charge of that model until you have rendered it completely safe -in the case of an electric model by disconnecting the power source - and you should have hold of the transmitter until then.

I think I have said in an earlier post- I have learnt so much in just a few days from advice here. That's the downside of learning on your own- learning is hard - on the other hand, it is quite fun making the transition from trying to keep a plane in the air without having to put all the bits into a bag, to actually making it do what you want!

Edited March 2, 2023 by paul devereux

[Frank Skilbeck]

11 hours ago, Peter Jenkins said:

Good point Peter.

 

The other pojnt is that if the radio equipment has a Failsafe facility it must be set.  All 2.4 GHz radio has a failsafe facility and most 35 MHz radio does.  If I remember correctly, all Dual Conversion Rxs have a failsafe.

Not dual conversion but 35 mhz PCM receivers did, and MPX IPD receivers, most standard 35 MHz PPM receivers do not have failsafe..

[Brian Cooper]

Modern computer radios are fabulous and seem to have an endless number of features and "toys" to play with. 

Generally speaking, the higher to price, the greater the sophistication of the radio.

 

However, don't be fooled into thinking that having a more sophisticated (expensive) radio will be a shortcut to learning the skills required to fly a model. 

 

Quite the reverse in fact... because to get the best from a high-end radio, you need to have an in-depth familiarity with the intricate details of flying and have a working knowledge of whatever electronic inputs, mixes or alterations are required to achieve any particular outcome. 

 

Enjoy the journey of learning the skills. . . . It never ends.

[GrumpyGnome]

Agree with 90% of what Brian says...... except..... apart from bluetooth software updates, and a built in camera, a Radiomaster TX16 or Jumper equivalent offers sophistication pretty much on a par with a Spektrum costing almost 10 times as much...... nowhere near on a par with a quality 'feel' though!