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Old Sep 11, 2013, 01:22 PM
Herd WarpSquad
Moto Moto's Avatar
United States, AL, Guntersville
Joined Dec 2012
1,071 Posts
Quote:
Originally Posted by kha View Post
I will throw one of my brand new HawkEye units on powermeter today. I had an earlier version and measured 770mW of output on it.
I suspect I've damaged the RF module in my transmitter. I have ordered another Hawkeye set, plus a replacement RFM23B module. I really want this to work.

I'll program the new Tx, with the antenna installed, with a 5V FTDI and without external power to the module. Is that correct? Are there any other cautions or requirements?

And thanks for your work on this, kha. Sorry to be a nuisance with these noob problems.
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Old Sep 11, 2013, 03:15 PM
Moscow
Joined Feb 2012
92 Posts
Hi Kha!

May I leave an option request?

It would be delicious to have one channel assigned to power control of Tx.

Let's say Ch14 will be attached to any switch on the radio. So we have 50% power most of the time, while flying around. But if FS happens or so, I can just switch the switch and get 100% immediately. Simple as that! It will also help to save battery. The power of RF module can be controlled by 6D register.

This is not my idea, it's from one very popular Russian LRS. And everybody like it!
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Old Sep 11, 2013, 04:05 PM
Stuart
srnet's Avatar
UK, Cardiff
Joined Dec 2008
3,292 Posts
Quote:
Originally Posted by shuricus View Post
The power of RF module can be controlled by 6D register
On the RFM22B (100mW) you can control the power output from about 1mW to 100mW.

On the RFM23BP (1W) the power setting register does not have much effect, its basically a 1W only device, although you could reduce power by varying the power supply.
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Old Sep 11, 2013, 04:27 PM
Moscow
Joined Feb 2012
92 Posts
I personally know high class engineer who measured the power on high end professional equipment, and he easily got 50% power reduction by register changing.

Here is nice form factor by the way of that device!





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Old Sep 11, 2013, 04:57 PM
Registered User
Joined Sep 2013
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HawkEye Tx DOA

Received 3Nr Rx and 1Nr Tx from HawkEye china yesterday, due to work only just got round to loading OpenLRSng firmware....

....using my trusty TinyOSShop.com FTDI, updated the 3Nr Rx no problem at all, but on connecting the FTDI to the Tx, I get message in Windows that the USB device is unrecognised, and in Arduino that there is no Com port.

Tried unplugging the USB lead and replugging... still not recognised by Windows.

A couple of mins have gone by and I pick up the Tx/FTDI to discover that the FTDI is very hot.... pull USB pretty sharply and take a close look at the PCB of the Tx... no obvious shorts or linked tracks (in fact the quality of the soldering looks pretty good).

So folks... any suggestions?

Just to check that the FTDI is okay I subsequently reflashed an old HK Orange Rx that I had lying around... with no problems at all.

Seems I have a bad HawkEye Tx.
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Old Sep 11, 2013, 05:01 PM
Stuart
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UK, Cardiff
Joined Dec 2008
3,292 Posts
You really want to be measuring the actual radiated power from a real antenna, out in the field for real. After all its the real radiated field that the receiver responds to, not the measurements on a lab instrument.

See enclosed, its plot of how much the real world radiated power of a RFM23BP varied with voltage and between the max and min settings of the power register.

I saw a variation of only 2.5dB between min and max power at 5V.

I raised it as a query with Hope technical department, I was looking at using it in a small satellite, but it was essential to be able to turn the power down to 100mW or so. Hope technical said;

"You don't do anything wrong about this. It's correct that there is not much
power difference when you change power setting register. Because RFM23BP
include an external PA on the module, so software setting of power cann't
change much of output power."
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Old Sep 11, 2013, 05:19 PM
Herd WarpSquad
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United States, AL, Guntersville
Joined Dec 2012
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Quote:
Originally Posted by ConeyBasher View Post
Received 3Nr Rx and 1Nr Tx from HawkEye china yesterday, due to work only just got round to loading OpenLRSng firmware....

....using my trusty TinyOSShop.com FTDI, updated the 3Nr Rx no problem at all, but on connecting the FTDI to the Tx, I get message in Windows that the USB device is unrecognised, and in Arduino that there is no Com port.

Tried unplugging the USB lead and replugging... still not recognised by Windows.

A couple of mins have gone by and I pick up the Tx/FTDI to discover that the FTDI is very hot.... pull USB pretty sharply and take a close look at the PCB of the Tx... no obvious shorts or linked tracks (in fact the quality of the soldering looks pretty good).

So folks... any suggestions?

Just to check that the FTDI is okay I subsequently reflashed an old HK Orange Rx that I had lying around... with no problems at all.

Seems I have a bad HawkEye Tx.
Sounds like the current load on the board overloaded the ftdi interface. I'm also having Hawkeye Tx problems that may be due to a brownout with the ftdi interface. I was able to program the module, but arduino reported flash verification errors on most uploads. Since then, it works but the range is very short.

The Flytron forum says to not use VCC from the ftdi interface on their 1W module. I haven't seen anything about that for these boards, but it seems that may be the problem.
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Old Sep 11, 2013, 05:43 PM
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Canada, QC, Montreal
Joined May 2013
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Kha keeps saying that you need to use the radio's power, and not the usb-serial adapter's power, have you tried that?
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Old Sep 11, 2013, 06:34 PM
Registered User
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That's right - HawkEye Tx didn't work out with FTDI power for me. With radio power - just fine.
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Old Sep 11, 2013, 09:49 PM
Herd WarpSquad
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United States, AL, Guntersville
Joined Dec 2012
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Thanks for the info, gentlemen. I reflashed my Tx module with radio power, with the 3.3V/5V jumper removed on the ftdi interface. The flash verified without errors. So I took it outside for a range test, and made it all the way to the end of the street (250 yards) where it lost signal before and still had a good signal. It did get some beeps on the way, but seemed pretty solid. I think it's airworthy.

Anybody care to theorize on why flashing with radio power would fix the range? Maybe because the EEPROM wasn't successfully programmed?
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Old Sep 12, 2013, 03:37 AM
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Well, for me it's simple - I could not flash it with FTDI power at all....
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Old Sep 12, 2013, 04:41 AM
kha
openLRSng haxor
Finland, Espoo
Joined Mar 2011
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Quote:
Originally Posted by RocketMouse View Post
Well, for me it's simple - I could not flash it with FTDI power at all....
Yeah that is because the dcdc converter on the tx does not like being fed backwards and basically shorts the output side. You can actually uae ftdi power (5v) by wiring it to the 5pin transmitter connector (3rd pin).
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Old Sep 12, 2013, 05:00 AM
Moscow
Joined Feb 2012
92 Posts
Your post looks very convincing to me. But on the other side lots of our RC users reported that they have really significant power reduction.
This fact is also proved by the developer of Russian LRS Expert. And I cannot argue that, because this guy is really professional.

Expert LRS is just hardware similar to OpenLRS 1W, but because of very high quality protocol developed, this LRS easily works for 50km distance!!!!!!!!!!
OpenLRSng currently is far away from such a results, right? So this guy knows what he is doing!

And here you can see measurements made by professional equipment on register power change.



Num / mW /Pmax-Pmin, dB
8 / 120 / 3.5
9 /220 / 3.2
10 / 500 / 2.4
11 / 720 / 1.5
12 / 780 / 1.3
13 / 840 / 1.0
14 / 900 / 0.5
15 / 960 / 0.35

So I'am out of that arguing, cos I can only see what others say.

But if Kha will add this function to his FW everyone will manage to check it by himself.

Quote:
Originally Posted by srnet View Post
You really want to be measuring the actual radiated power from a real antenna, out in the field for real. After all its the real radiated field that the receiver responds to, not the measurements on a lab instrument.

See enclosed, its plot of how much the real world radiated power of a RFM23BP varied with voltage and between the max and min settings of the power register.

I saw a variation of only 2.5dB between min and max power at 5V.
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Old Sep 12, 2013, 05:25 AM
Stuart
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UK, Cardiff
Joined Dec 2008
3,292 Posts
Quote:
Num / mW /Pmax-Pmin, dB
8 / 120 / 3.5
9 /220 / 3.2
10 / 500 / 2.4
11 / 720 / 1.5
12 / 780 / 1.3
13 / 840 / 1.0
14 / 900 / 0.5
15 / 960 / 0.35
The dB figures do not make sense.

Your showing a difference between max and min power of 3.15dB, close to what I measured. That appears to tie up with the scope plot which seems to be 2dB per division.

1W is 30dBm, 3dB down from that is 500mW.

1W to 120mW is about -9dB down.
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Last edited by srnet; Sep 12, 2013 at 05:33 AM.
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Old Sep 12, 2013, 06:22 AM
Moscow
Joined Feb 2012
92 Posts
500mW that is exactly what we need!
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