RR Rated M For Mature
HOME   rrTV-PHOTO   GALLERIES   MY GALLERY   HELP-FAQ
myHOME PM pmRR MEMBERS 508 ONLINE 20 EVENTS SEARCH REGISTER  START HERE
 
13 pages [ <<    <     1      2     ( 3 )     4      5     NEXT    >> ]32505 viewsPOST REPLY
Hobby Hut . Heli Wholesaler . JR-Spektrum

.
.
Radio - JR & Spektrum DSM > My experience with the DX7 spread spectrum radio
 
 
Augusto
Elite Veteran
Location: US

My Posts This: Topic  Forum

The reason why the 40dB attenuation button is necessary is because the antenna being so short can't be collapsed or disconnected as in the regular 72MHz system.

To get an idea of what it means to do a 40dB attenuation you can use the free space path loss equation.

Path Loss = 32.45 + 20*log(f) + 20*log(d)
(f=frequency in GHz and d=Distance in meters)

So for instance if you're about 20 meters (about 21 yards) from the 2.4GHz radio your free space path loss is:
32.45 + 20*log(2.4) + 20*log(20)
32.5 + 7.60 + 26.02 = 66.12dB

When you click the button and add 40 dB is like you went 2000 meters away (2Km away) or 1.25 miles away.
32.45 + 20*log(2.4) + 20*log(2000)
32.5 + 7.60 + 66.02 = 106.12dB (40 db higher loss)

So in other words when you're at about 20 meters away and click the button the signal becomes equivalent to you going 2Km (1.25 miles) away and doing a range check.

Augusto.

Avant Aurora Ultimate
11-29-2006 Over year old.
PROFILE   PM   EMAIL   POSTS   BUDDY   IGNORE  
 
 
Yug
rrMaster
Location: UK. Herts

My Posts This: Topic  Forum
Augusto - how do you rate the DX7 Tx in terms of it's stick feel and weight ?
11-29-2006 Over year old.
PROFILE   PM   EMAIL   POSTS   BUDDY   IGNORE   GALLERY
 
 
Barney
Key Veteran
Location: Inverness Scotland

My Posts This: Topic  Forum
JKos

I was thinking more of the spectrum Tx modules rather than the complete Tx which I'm sure will be available in the not to distant future. The one Ive seen has a short aerial on the Tx module itself.
11-29-2006 Over year old.
PROFILE   PM   EMAIL   POSTS   BUDDY   IGNORE   GALLERY
 
 
Augusto
Elite Veteran
Location: US

My Posts This: Topic  Forum
Yug,

The sticks feels great. The release version comes with ball bearings. The weight was the only issue I posted about being that that the lack of a large antenna makes it a bit unbalanced for my taste but it's not really a big deal. I'm just too picky.
I did learn a trick from someone that told me he learned from Curtis about a piece of the hard side of a velcro at the bottom of the transmitter to make it stick to your t-shirt while you fly.


Barney,

There will be no transmitter module released for that new system.
The reason is that it's impossible to get the speed that the DX7 system has if you have to wait for the original transmiter to encode and put the info into a pulse train and then for the SS module to pick it up decode it, digitize it and re-encode, re-modulate it and spread it again into the spread spectrum signal. When they looked at the time it takes they dropped the idea of a module completely so don't wait for a module to come out.

Augusto.

Avant Aurora Ultimate
11-29-2006 Over year old.
PROFILE   PM   EMAIL   POSTS   BUDDY   IGNORE  
 
 
trevorz
Senior Heliman
Location: Calgary, Alberta Canada

My Posts This: Topic  Forum
Thanks Augusto for all the info.

If only it was an 8 channel I would buy it now, but alas the JR7000 gyro needs that extra channel.

I think the module being referred to above is the XPS one.

Regards,
Trevor.
11-30-2006 Over year old.
PROFILE   PM   EMAIL   POSTS   BUDDY   IGNORE   GALLERY
 
 
Yug
rrMaster
Location: UK. Herts

My Posts This: Topic  Forum
Thanks Augusto. Looks like it's just a case of waiting for the UK committes to wake up and give it the thumbs up.
One more question, being 2.4Ghz, I wonder how well it would work with a 2.4GHz video downlink mounted on the heli?
11-30-2006 Over year old.
PROFILE   PM   EMAIL   POSTS   BUDDY   IGNORE   GALLERY
 
 
greg
Key Veteran
Location: Yorkville, IL

My Posts This: Topic  Forum
I think modules adapted to any of the existing systems/brands would not be a good idea for the exact reasons stated by Augusto above.
11-30-2006 Over year old.
PROFILE   PM   EMAIL   POSTS   BUDDY   IGNORE   HOMEPAGE   GALLERY
 
 
jab1969
Veteran
Location: Fort Worth 76137, Texas , USA

My Posts This: Topic  Forum
Hey Augusto, What about the moduels from extream power systems???? Are you saying that If I use one of their moduels in my 10X and their receiver it wont be faster?

Xtreme Power Systems, @Signs
11-30-2006 Over year old.
PROFILE   PM   EMAIL   POSTS   BUDDY   IGNORE   HOMEPAGE   GALLERY
 
 
THX1138
Elite Veteran
Location: Plainfield, IN

My Posts This: Topic  Forum
We got the DX7's in today at the LHS I work at and I am pretty impressed. The RX is much smaller than I expected and this is a pleasant surprise. I think I will pick one up for plank use and maybe a T-rex 600. Looks good and it would seem that they are very functuional radios. Now we just need Paul to make some Spektrum modules for existing radios and life will be good.

Lou

Stupid deer.
11-30-2006 Over year old.
PROFILE   PM   EMAIL   POSTS   BUDDY   IGNORE   GALLERY
 
 
OICU812
rrProfessor
Location: Grande Prairie, Alberta, Canada

My Posts This: Topic  Forum
thx....

Quote 
There will be no transmitter module released for that new system.

...Once upon a time there were Nitros, flybars and frequency pins...
11-30-2006 Over year old.
PROFILE   PM   EMAIL   POSTS   BUDDY   IGNORE   GALLERY
 
 
COOKIEULT70
Senior Heliman
Location: CAMERON PARK, CA

My Posts This: Topic  Forum
Are there any plans to release a 8 or 9 channel system? I have a plank that has 4 wing servos so I need at least 8 channels. Or does the battery not plug into one of the 7 channel ports on the receiver?

GAHH!!! Someone call 911!! My wallet is bleading heli parts!!
11-30-2006 Over year old.
PROFILE   PM   EMAIL   POSTS   BUDDY   IGNORE   HOMEPAGE   GALLERY
 
 
Dood
Elite Veteran
Location: WI

My Posts This: Topic  Forum
My thoughts,

I figure that since I was considering a 9303, and if there was a possible trend going on, I would hold off until there was a DX9, or the 9303 DSM equivelant.

3 years is enough time wasted. Taking a break for a while.
11-30-2006 Over year old.
PROFILE   PM   EMAIL   POSTS   BUDDY   IGNORE   HOMEPAGE   GALLERY
 
 
Micro-Maniac
Elite Veteran
Location: Pasco,Washington Formerly: Captain Chaos

My Posts This: Topic  Forum
Quote 
Or does the battery not plug into one of the 7 channel ports on the receiver?

Quote 
Notice how the battery is connected in a horizontally aligned slot below the 7 channel ones.
Separate battery connection aside from servo connections - So all 7 are free.
11-30-2006 Over year old.
PROFILE   PM   EMAIL   POSTS   BUDDY   IGNORE   GALLERY
 
 
hootowl
rrProfessor
Location: Garnet Valley, Pa.

My Posts This: Topic  Forum
The menu screens almost look Futaba 9C. Is this a coincidence?

"Look, when I was a kid, I inhaled frequently. That was the point."
11-30-2006 Over year old.
PROFILE   PM   EMAIL   POSTS   BUDDY   IGNORE   HOMEPAGE   GALLERY
 
 
THX1138
Elite Veteran
Location: Plainfield, IN

My Posts This: Topic  Forum
The DX7 and 7202 are identical(with the exception of spectrum) that is where the programing comes from.

Lou

Stupid deer.
11-30-2006 Over year old.
PROFILE   PM   EMAIL   POSTS   BUDDY   IGNORE   GALLERY
 
 
JKos
Elite Veteran
Location: City of California in the state of Maryland

My Posts This: Topic  Forum
> The DX7 and 7202 are identical

Almost... The DX7 has a timer (up or down) whereas the 7202 does not.

- John
11-30-2006 Over year old.
PROFILE   PM   EMAIL   POSTS   BUDDY   IGNORE   GALLERY
 
 
Yug
rrMaster
Location: UK. Herts

My Posts This: Topic  Forum
JKos - I remember the latency on the 9C between channels 1 and 6 in PCM mode was about 120ms; what;s the latency in PPM mode ?
Just wondering what kind of benefit the 9C would get with using the XPS as it interfaces via PPM.
11-30-2006 Over year old.
PROFILE   PM   EMAIL   POSTS   BUDDY   IGNORE   GALLERY
 
 
JKos
Elite Veteran
Location: City of California in the state of Maryland

My Posts This: Topic  Forum
Yug,
In PPM mode, the 9C has a minimum latency of 50 ms and a maximum latency of 82.3 ms for eCCPM use (32 ms to 59.3 ms for a normal swash). So even if the XPS system added zero latency (obviously not possible), the DX7 would still whip its butt at 14 ms min to 40 ms max.

- John
11-30-2006 Over year old.
PROFILE   PM   EMAIL   POSTS   BUDDY   IGNORE   GALLERY
 
 
hootowl
rrProfessor
Location: Garnet Valley, Pa.

My Posts This: Topic  Forum
Quote 
The DX7 and 7202 are identical

Are they made by the same company, Futaba?

"Look, when I was a kid, I inhaled frequently. That was the point."
11-30-2006 Over year old.
PROFILE   PM   EMAIL   POSTS   BUDDY   IGNORE   HOMEPAGE   GALLERY
 
 
Yug
rrMaster
Location: UK. Herts

My Posts This: Topic  Forum
thanks
11-30-2006 Over year old.
PROFILE   PM   EMAIL   POSTS   BUDDY   IGNORE   GALLERY
 
 
13 pages [ <<    <     1      2     ( 3 )     4      5     NEXT    >> ]32505 viewsPOST REPLY
E-flite . Fast Lad Performance . Ace Hobby

.
.
Radio - JR & Spektrum DSM > My experience with the DX7 spread spectrum radio
 Print TOPIC Advertisers 

Subscribe to This Topic

Sunday, November 8 - 5:31 am - Copyright © 2000 - 2009 runryder.com | email | link to rr | START HERE | NF