Range: Traditional receiver VS sats only

[Laowai]

Anyone has any input on this? Is the range the same?
Everyone feels comfortable flying a 700e with just two sat instead the full receiver?
I know that other FBL recommend to use sats with small helis only...
What is the position of Skookum on this?

[kimmik]

Sats same range as full receiver. Try a range test. The low power mode is 1/30 range of full range mode. I always get 30m+, which means flying range is about 1km.

[Yogi1]

No problem what so ever on a 700e two JR carbon sats. The sat recievers are the the same electronics that are found in the full size recievers sans the servo bus plugs.Yogi

[Laowai]

Mmmmmm.... Well, not exactly.
The DMSS receiver contains two totally independent receivers inside one box, each with its own pcb and antenna, plus a satellite antenna that also transmits telemetry.
It is two receivers with three antennas Vs. one receiver with two antennas.
Hence my question

[desertstalker]

Originally Posted by Laowai

Mmmmmm.... Well, not exactly.
The DMSS receiver contains two totally independent receivers inside one box, each with its own pcb and antenna, plus a satellite antenna that also transmits telemetry.
It is two receivers with three antennas Vs. one receiver with two antennas.
Hence my question

A sat IS a receiver, the SK is not doing RF reception or modulation decoding, its just interpreting a serial data-stream of channel values. So you have 2 receivers on a SK720 which is sufficient for any heli purpose the SK is.

The reason for sats is path diversity not range, so having an extra RX in the main unit is not hugely helpful as they are physically next to each other (unless the leads are long).

The majority of FBL systems use 2 sats, I dont recall any significant reports of reception issues (there are always a few of course but not many considering).

[Laowai]

Anyway, I've found a way to extend the range of the XG8. A 1 Watt booster.
It is NOT legal in Europe! But it increases your range to six miles and delivers peace of mind for just a few dollars....

[georgi UK]

=] try it out!!

[jcflyer]

Originally Posted by Laowai

Anyone has any input on this? Is the range the same?
Everyone feels comfortable flying a 700e with just two sat instead the full receiver?
I know that other FBL recommend to use sats with small helis only...
What is the position of Skookum on this?

I have been flying my 550, 600 pro, and 700 V2 with just 2 sats without any problems for over a year now.

[Laowai]

I definitely can't feel at ease with just the two sats... I have seen already several times the "lost RX signal" message!
Georgi: I have it running already. Works like a dream.
Before, during range check, it was 30 metres. Now, everything the same, is 600 metres
With the TX on the grass and the heli inside the car, it goes into failsafe at about 6 km!!

[georgi UK]

Originally Posted by Laowai

With the TX on the grass and the heli inside the car, it goes into failsafe at about 6 km!!

=] that's incredible! wicked!

[nickyd]

Hi
Can you post a link to the 1watt booster you used please. Really interesting.

Thanks

Nick

[Laowai]

This is ALL you need (other than your 2.4ghz radio and receiver, of course):

http://www.ebay.com/itm/NEW-2-4Ghz-W...item3a7839d6d4

http://www.ebay.com/itm/SMA-male-to-...item3371cedcaf

http://www.ebay.com/itm/RP-SMA-to-U-...item4ab13a499f

http://www.ebay.com/itm/Hobbywing-3A...item460670fd97

And other than the power supply, all is plug and play. No splicing or soldering... You go from 150mW to 1000mW.
I say again: NOT legal in Europe

[georgi UK]

=] that's a ground station?

[Laowai]

That's it, Georgi!
Our FPV friends use it without problems. Interference is not an issue as 2.4ghz radios skip from one frequency to another constantly.
This is a 1w booster. There are 2W (14km), 5W (35km), etc. Remember that NASA communicates with the moon with just 20W!
And whatever you do, don't fall into the trap of using higher gain antennas. You can think of gain as a lens: The higher the gain the more focused is the beam. Reachs further, but the beam is narrower.
Don't go over 5dBi for the antenna to have proper coverage...

[georgi UK]

=] what could they do to you in Europe if you "had" one??! roughly?

[Laowai]

Well.... In the case that someone finds out, and then denounces you to the authorities, and they then act on your case...
Something like 25,000€ plus some jail time... In Europe is even forbidden to discuss this in Internet forums. Somewhat like where to download pirate software.
This doesn't mean that people don't do it, of course. They just change their location on their profile so it looks like they live in the U.S
I guess is a matter of common sense. Where I live it is legal. However, two guys went two months to jail the other day. They used one of these boosters with a plane and FPV. The motor gave up 18km away and fell in the middle of a downtown street. The police tracked them down...

[teamdavey]

Just because you can does not mean you should...............(Jurrasic Park)

[Laowai]

Very true.
I use it because I fly my big helis like I fly my planes: Doing aerobatics at top speed. I just can't bring myself to do tic-tocs or chaos with an 800. I have my 450s for that purpose.
Now, the 700 and the 800 go better than 130km/h and can get far in the blink of an eye. I lost one once in a situation like this, where it lost link and failsafed into a river.
The booster is my insurance that RX link will not be an issue anymore.

[desertstalker]

Originally Posted by Laowai

It is NOT legal in Europe! But it increases your range to six miles and delivers peace of mind for just a few dollars....

It might be legal here, depends on how many separate frequencies the TX hops over (no good for DSM2).

I would also be worried that a cheap amp (and those qualify) would put out so much extra noise on other channels that it would interfere with other pilots. Its not good policy to shoot down your mates aircraft. You also just lost any FCC or similar approval that your TX has buy modifying the output stage, so may not be legal anywhere.

DSM2 with a single Sat on a pole was good for over a mile... more than enough for any heli. You arnt losing signal from range, shadowing is the likely culprit, and the reason for 2 correctly positioned sats so that no CF or metal blocks signal.

NASA may reach the moon on 20W, but it is a tightly focussed beam so its intensity is several orders of magnitude higher than would be received using a broad-area transmitter (like your TX) that radiates in all directions.

[Laowai]

Stalker:
I am not trying to convince anyone about using a booster. Just to show what I (and others. Just google) use for extending the range.
The risk of affecting others is zero. In our place we have FPV guys transmitting with much more power than this and there is no problem. The DMS/FHSS systems have been designed with this scenario in mind. If we were transmitting, say, in 70MHZ it would be a different story. It will also affect wifi/cordless phones around but again, just for some milliseconds until jumping to other frequencies.
No need to increase the output for losing your type approval. Our radios have a non-replaceable antenna for this very reason. Just changing the antenna (or putting it on a pole) will make the radio non-compliant and thus not legal.
In many places (U.S., in example) 2.4Ghz is an unregulated band, as the 40-meter/27Mhz is, and you can transmit as you please.
And the 20W to transmitt to the moon: Yes. Our Tx antennas are typically 2dBi gain for a ~160 degrees vertical coverage. 10dBi gain gives you ~100 degrees. All this in supposedly "omnidirectional" antennas where the coverage has a doughnut shape.
This reduction in coverage means an increase in range. If you can imagine a cone generated around the axial line of the antenna, in our 2dBi antenna this cone is a weak signal area of ~20 degrees. In a 10dBi antenna this "empty" cone is ~80 degrees. This means that the weakest signal possible is reaching your helicopter when the antenna is pointing directly at it.
A directional antenna, usually dish-shaped, inversely transmit in a tight cone, as you have well said.