New JRX9303 2.4 Gig - legal power in UK or not???

[Rick Rotorhead]

Like many I'm casting avaricious eyes over the new JR tranny - at least as good as my current Fut9C super with integrated 2.4 Spektrum technology - luvverly!!!! Trouble is you can only get them in the USA right now!

However, I'm a little worried that the US spec may include a higher power output than we are allowed to normally purchase in UK. (As an example: I understand the the Spektrum DX7 from American retailers features a 300mW output, but the same Tx in UK is 'de-tuned' to just 100mW).

So, is this true also of the JR X9303? If I get one from the States will I be infringing our permitted 2.4Gig Tx spec - in which case I should think that would invalidate my BFMA insurance......

Any advice or views greatly appreaciated before I commit to the considerable funds......

[Ashley Davis]

http://www.rcheliaddict.co.uk/showpo...8&postcount=19

[Rick Rotorhead]

VMT Ashley, Well, loads of info, yet still little clarity!

If I read it all correctly - the new JRx9303 as retailed in America is technically illegal to use in UK and I should wait for the officially type approved and reduced output European spec Tx.

That said, the US version would work perfectly well in UK and not cause any issues - but a third party damages claim may be rejected by the BMFA insurers, if they found out I was using a non-euro spec Tx.

For that reason also, UK clubs could dis-allow flying with these Txs'.

What a pain! I don't know how long I'd have to wait for JR to release a modfied X9303 to the UK market. Looks like I'll have to settle for the DX7 as an interim measure then!
Or, maybe take a second look at the Futaba FASST conversion module for my 9C - as I regard it as only a stop-gap measure......though at least I'd get to keep all my fav 9C features/menus etc

I guess I need to think on it yet more....................

[raptorheli2]

i would hang off for a while yet. there is problems with the spektrum dx7 power output here in UK. horizon hobby have issued a bulletin but word on the street is they will want 99% of radios back to de-tune them. i.e the range will be same as dx6 to be legal here.

fasst on the other hand doesn't suffer from this due to the way it implements 2.4 and will be full range off the bat.

i'm going to call spektrum/horizon uk and see if they want my dx7 back as it was first batch radio. if it wasn't for robbe no one would have noticed this power problem.

cheers

[mchristyuk]

Rick/Raptorheli2,

This is straight from Paul Beard regarding the power situation on US/UK sets:

"European type approval restricts our 2.4GHz output power to +20dBm (100mW).

There's less than 3dB difference in the peak output power between EU and US DX systems. However there is only a very minor reduction in range and no impact on selectivity. And both versions are classified as full range systems capable of controlling any RC aircraft with plenty of margin.

The 3dB difference is very minor when you consider the total path budget of the systems:

Path = RX sensitivity + RX coding gain + TX power
98 + 18 + 22 = 138dB for the US
98 + 18 + 19 = 135dB for EU versions."

Now both me and my old man had one of the early DX7's that were supposed to be way over the top in terms of power.. but when measured were with in the regulations... so I think we can put that myth to bed..

The X9303 will be called the DSX9 when it arrives here and we should see it before the year is out. Yes the power will be slightly down on the X9303 as you can see above.. but will make next to no difference.

I am running the Spektrum module in my PCM10x in my all carbon Vibes and have had no range problems what so ever.. was very relaxing flying at the Nationals knowing that I couldn't be shot down by somebody buying new "toys" in the trade area...

Cheers

Mark

[jiberjaber]

3dB isnt very minor when you consider it is in effect a doubling of the power!

Just for interest, how did you measure the power output of your DX7?

[raptorheli2]

thanks for clearing that up but it is a power drop without question, wether that equates to a noticable problem or not i wouldn't know but there are claims in germany who have the decreased power that range is half what it was.futaba apparently are not bound with the same problem spektrum are due to the shifting in fasst.

it is not a myth, horizon have issued a bulletin....some radios have a problem and people should call them.

cheers

[SRH990]

The major issues seem to be in France where the authorities have limited power output below that of the rest of Europe, apparently Futaba FASST modules have a switch to reduce power output specifically for France.

[Steve]

3dB isnt very minor when you consider it is in effect a doubling of the power

Absolutely right.

The Decibel scale is logarithmic, so (without going into the maths of it all), a 3dB rise, say from 85dB to 88dB represents a doubling of output power, and this applies throughout the range, so an increase from 135dB to 138dB is also a doubling of output.

[moyesboy]

Seems there is a lot of speculative and conflicting info about on this subject.
If you are flying a really big model that might test the range, then you should do a full range ground test I guess.

If there was a problem with the UK spec of these radios for flying normal sized models in a normal manner it'd be well known by now. For sure the vocal "sticking to 35Mhz for now" section of the community would make sure we all knew about any problems they saw!

[chugga-bug]

If there was a problem with the UK spec of these radios for flying normal sized models in a normal manner it'd be well known by now. For sure the vocal "sticking to 35Mhz for now" section of the community would make sure we all knew about any problems they saw!

Think this pretty much sums it up in my mind.
If you're gonna fly any model to the point where you can barely see it then you're asking for trouble anyway. These radios have been around (legally) for 10 mths now and I can't recall reading anything about range problems.

[ChrisB]

Well i can fly my models up high until they are a dot in the sky and i dont lose range so i guess the DX7 is good enough as it is in the UK

[Sesame]

I'm getting a slating on one of my clubs forums for daring to say that I think 2.4 spektrum is good.

but noone can give me positive proof of major problems with the system itself. The only problems I can recall ACTUALLY happening have been the ones on the horizon pages, the AR6100 needing a reprogram, the capacitor failing, but ive been flying quite alot on mine for the last 6 months and ive not had 1 single glitch, nuthin, nada, nil.

i'm looking forward to the JR 9303 or whatever it will be badged to be released as im gonna go and get me one.

[ChrisB]

I'm getting a slating on one of my clubs forums for daring to say that I think 2.4 spektrum is good.

but noone can give me positive proof of major problems with the system itself. The only problems I can recall ACTUALLY happening have been the ones on the horizon pages, the AR6100 needing a reprogram, the capacitor failing, but ive been flying quite alot on mine for the last 6 months and ive not had 1 single glitch, nuthin, nada, nil.

i'm looking forward to the JR 9303 or whatever it will be badged to be released as im gonna go and get me one.

There are No real problems with the DX7 and the Sprktrum system at all,,most of the totally untrue dross and drivel coming out of peoples arses is down to the fact that the individuals spouting this crap are convinced that the new fangled system is flawed where as i am sure many will agree its proving itself more and more each day and at major events that use the system trouble free

[Sesame]

One person pointed out that there ar a couple of european countries that are banning the use of 2.4gig equipment. They made it sound like it was because there was concern over the safety but when I looked into it it appears it is because of overuse of the 2.4gig part of the spectrum and 2.4 for models is being phased out in 2009/2010.

But it is giving something for the non converts to point at and say told you so.