HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Oct 21, 2012, 04:47 AM
Registered User
Isle of Man
Joined May 2005
19 Posts
Surely the main point is that it will tell you when it's going out of range.....never had a problem with any of the receivers from 4-8 channel versions, except for one which was shielded by metallic covering(my fault!), which then gave me a "signal loss " warning at medium range but remained fully controllable.
pete52 is offline Find More Posts by pete52
Reply With Quote
Sign up now
to remove ads between posts
Old Oct 21, 2012, 08:05 AM
Professional idiot
Hampshire, UK
Joined Jun 2002
3,119 Posts
Quote:
Originally Posted by GordonTarling View Post
All that those dbm figures tell you is that one receiver is a bit more sensitive than another. What it doesn't tell you is what the range IS under specific conditions. e.g. if the -98dbm gave 2km range, the the -106dbm could probably give 4km range (guess!), but the average modeller will never usually know the difference unless he's flying out of sight.
I agree with you. So many things affect effective range. All I was originally pointing out was that some receivers had more range than others.

I never fly far away though I have clubmates flying 250cc 3D models, 2.5m fast turbine models & half scale gliders: they might be more concerned to know some receivers are likely to have better range than others.

Guess it is all a question of symantics. If one receiver had half the range of another I wouldn't call it full range. On the other hand if they were both out of line of sight in even a large model I guess you could say they are both full range (the extra range of one being of no use).

Just use what works. I based my receiver selection (currently 13) on Jeti website. R7 for small model, R6 for small/middle & R8 for middle/large.

Dave
wildpalms is offline Find More Posts by wildpalms
Reply With Quote
Old Oct 21, 2012, 08:13 AM
Professional idiot
Hampshire, UK
Joined Jun 2002
3,119 Posts
One of the really nice Jeti features is the output programming.

If receiver space is at a premium and you need the outputs just use 2 receivers: can take two five channel rx's and you have a 10 channel. Can locate them more easily as well.

When I wanted to test a second hand 50cc'er I put an R6 up front controlling throttle, choke & ignition. A second R6 put up near the wing tube controlling the 2 elevators, 2 ailerons & rudder. The output programming also let me dispense with the JR Matchbox on the elevator halves.

With Jeti there is no need for using Matchboxes or Powerboxes (other than power).

Dave
wildpalms is offline Find More Posts by wildpalms
Reply With Quote
Old Oct 21, 2012, 10:34 AM
Lou
Registered User
United States, VA, Waynesboro
Joined Dec 2005
5,560 Posts
Quote:
Originally Posted by wildpalms View Post
I agree with you. So many things affect effective range. All I was originally pointing out was that some receivers had more range than others.

Dave
True indeed. One of my older Spektrum receivers certainly had only 'parkflyer' range. Literally, if you got more than 100 meters out, the receiver would loose the signal. My confusion came from the Esprit web site not being clear on the documentation. As my purposes for this radio are for sailplanes, range is an issue for me.

Esprit Models does show this 7 channel range as being Parkflyer/mid-range
http://www.espritmodel.com/jeti-dupl...telemetry.aspx

This 5 channel range as being indoor/parkflyer
http://www.espritmodel.com/jeti-dupl...telemetry.aspx

This 9 channel range as being full range
http://www.espritmodel.com/jeti-dupl...telemetry.aspx

Esprit really, really should correct their web site. It would not hurt to put the dBm levels in there either.

As ZB has stated that all receivers are full range and other users have stated they have no problems with ranging then I am comfortable with purchasing the DC-16.
Lou is offline Find More Posts by Lou
RCG Plus Member
Reply With Quote
Old Oct 21, 2012, 12:37 PM
Registered User
Joined Feb 2006
75 Posts
One problem I have had in the past is the TX showing 0 and 0 on the 2 antenna at about 400 metres range and you then get an alarm.
The model glider in question had a carbon and kevlar fuselage, and carbon wings.
Even though the antenna were outside the fuselage, the carbon still masked the signal sometimes. Although I never lost control of the model, the warning messages were worrying.
The problem is that the TX power is 100mW, but the return TX power in the receiver is a lot less I suspect. When someone mentioned that the R7 power output is 6dbm and the R9 power output is 20dbm, that makes me think that the warning of low antenna and other telemetry will be lost sooner with the R7 than the R9 receiver. They probably still have out of sight range, but the telemetry fails sooner.
David
f3fisa is offline Find More Posts by f3fisa
Reply With Quote
Old Oct 21, 2012, 05:59 PM
Registered User
drice's Avatar
United States, CA, San Diego
Joined Jul 2004
433 Posts
I'm not sure I'm buying the R9 output being 20dBm, as that is, by my calculations, 100mW. If this is true, then the receiver is outputting the same power level as the Tx. Maybe it is, but this seems suspect to me.

Also, Gordon in post #150 mentioned the Rx sensitivity numbers varying from -98 to -106dBm. Keep in mind that every 3dB is a loss of 1/2 of the power, so the power being rx'd at -98dBm is 267% Greater than that being received at -106dBm. So a Rx rated at -106 would definitely have greater range.

I do NOT, however, have any idea what the attenuation factors are over distance...so I couldn't say what the extra 8dB might mean in terms of increased range.
drice is offline Find More Posts by drice
Reply With Quote
Old Oct 22, 2012, 01:27 AM
Registered User
Czech Republic
Joined May 2010
78 Posts
Low range/Mid range

Hi, the receivers that aren't situated in a plastic box (like current R5 or R7) are meant to be shorter range and dedicated to parkflyers. All others are full range with sensitivity -106dB. The new receiver R5/satellite on one box is now being prepared and it will have also a full range. Parameters will be similar like this one:
http://www.jetimodel.com/index.php?page=product&id=189

And yes, it is possible to program all settings of receiver/Spin through a Jetibox emulator.
MafRaf is offline Find More Posts by MafRaf
Reply With Quote
Old Oct 22, 2012, 03:19 AM
Registered User
Trevorh's Avatar
Hampshire, U.K.
Joined Jun 2008
1,896 Posts
I sometimes think we fret too much about these RF power and sensitivity figures. Before converting to 2.4GHz, I found that any electric model on more than three cells or 500w, especially if a uBEC was used, was almost certainly to suffer from interference, often to the extent that it could be a real struggle to achieve a safe operating range even for normal sport aerobatic flying. Since switching to Jeti Duplex all my previously glitch-ridden models have been rock solid, even the 9 of them fitted with R4 and R5 receivers. These are not park flyers

Before going the Jeti route, I did read of people using the system in extreme range situationsoccasionally getting 'loss of signal' alarms. However, I was heartened to hear that even then there was no loss of control of the model, suggesting that the return link fails before the uplink. This is good design to my mind, and should be a source of reassurance rather than concern.

Equally, the fact that Jeti are prepared to publish sensitivity figures for their receivers rather than vague marketing hyperbole gives me confidence that someone has thought this system through pretty thoroughly.

Of course, this same engineering thoroughness is probably the reason I am still waiting for my DS-16. . . . .
Trevorh is offline Find More Posts by Trevorh
Reply With Quote
Old Oct 22, 2012, 03:24 AM
Registered User
Isle of Man
Joined May 2005
19 Posts
+ 1 !
pete52 is offline Find More Posts by pete52
Reply With Quote
Old Oct 22, 2012, 04:18 AM
Supersonic Engineering
GordonTarling's Avatar
UK, Greater London, Uxbridge
Joined Mar 2001
3,118 Posts
+2!

I occasionally receive a 'low signal' alarm when flying my electric Aghusky tug at great height/range, but I've never had even a hint of loss of telemetry or control - this is with an R10 receiver.
GordonTarling is offline Find More Posts by GordonTarling
Reply With Quote
Old Oct 22, 2012, 06:14 AM
Professional idiot
Hampshire, UK
Joined Jun 2002
3,119 Posts
Quote:
Originally Posted by MafRaf View Post
Hi, the receivers that aren't situated in a plastic box (like current R5 or R7) are meant to be shorter range and dedicated to parkflyers. All others are full range with sensitivity -106dB. The new receiver R5/satellite on one box is now being prepared and it will have also a full range. Parameters will be similar like this one:
http://www.jetimodel.com/index.php?page=product&id=189

And yes, it is possible to program all settings of receiver/Spin through a Jetibox emulator.
This contradicts Jeti USA who are saying they are all full range and Jeti CZ who actually have different figures for a number of the hard cased receivers.

Quote:
Originally Posted by GordonTarling View Post
+2!

I occasionally receive a 'low signal' alarm when flying my electric Aghusky tug at great height/range, but I've never had even a hint of loss of telemetry or control - this is with an R10 receiver.
Same here. When I originally flew my 88" Extra on a pair of R6's it happened even more.

Since the official line is that they are full range none of this dbm stuff matters. In four years of flying Jeti Duplex I've not had any trouble and that is what really counts :-)

Dave
wildpalms is offline Find More Posts by wildpalms
Reply With Quote
Old Oct 22, 2012, 06:16 PM
Lou
Registered User
United States, VA, Waynesboro
Joined Dec 2005
5,560 Posts
Now I am generally confused. I am unwilling to put a 5 channel 'parkflyer range/full range/unknown range' we are not sure what range receiver in a very expensive glider and have the glider fly away. Nor am I willing to stuff a 9 channel receiver into a RES glider.

Until JETI USA and JETI straighten out their published specs the JETI DC-16 and about $550 of JETI goodies are off my buy list.

Why in the world, JETI did not make a full range 4 or 5 channel receiver is beyond me.
Lou is offline Find More Posts by Lou
RCG Plus Member
Reply With Quote
Old Oct 22, 2012, 08:27 PM
Registered User
Geoff_S's Avatar
Brisbane, Australia
Joined Feb 2002
1,081 Posts
Obake, don't lose sleep over it. The R5 will be fine. I have used several for a number of years in slope soarers (as well as park flyers) without ever receiving a warning about low signal strength, let alone complete signal loss. For bigger gliders I have used R6, R8 and R9's but ony because they have had more than 5 servos.

If you want the increased sensitivity of the larger receivers, get an R6 or R9, take the cover off and heatshrink it instead - the size then will be very similar to an R5 anyway. Fly it and have fun, enjoying the peace of mind that continuous signal strength and rx battery voltage telemetry gives you.
Geoff_S is online now Find More Posts by Geoff_S
Reply With Quote
Old Oct 23, 2012, 12:06 AM
Professional idiot
Hampshire, UK
Joined Jun 2002
3,119 Posts
I think it is clear now. I messed things up by answering the question before Jeti USA. I'll steer clear of sticking my oar in in future :-)

Esprit has stated above that they are all full range. Should give you confidence to use whatever suits space/cost/cannel count.

Dave
wildpalms is offline Find More Posts by wildpalms
Reply With Quote
Old Oct 23, 2012, 02:59 AM
Registered User
Joined Sep 2004
15 Posts
Why there are two different prices for DC-16 ,$1295 $1090 ?
coldsteel is offline Find More Posts by coldsteel
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
New Product Jeti 2.4GHZ system with telemetry, easy-to-use sensors, and audio alarm! Julez Radios 1846 May 27, 2014 08:47 AM
Help! Can I run a 2.4GHz Radio and a 2.4GHz FPV system? MaNDoWn FPV Talk 14 Feb 08, 2014 12:47 PM
Discussion Jeti Duplex DC-16 Radio & Profi Wireless Downlink. Monitor/Record A/V/mAh/Speed real Esprit Model Radios 16 Jun 16, 2012 08:11 AM
Help! Jeti Duplex / updating firmware to EX VinceHaworth Radios 1 Feb 07, 2012 05:04 AM
Question Official Jeti DUPLEX 2.4 Range? Jose E Bruzual Hobby Express (Formerly Hobby Lobby) 3 Jun 01, 2009 11:58 AM