Galloping Ghost Rand actuator summay

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jmendoza
Posts: 158
Joined: 18 Feb 2018, 23:07

Galloping Ghost Rand actuator summay

Post by jmendoza »

I have attached a link to Tom Mavracics site where you can see the Summary of Rand actuators I wrote. Tom graciously added excellent photos of all the different models and variations to make it comprehensive in every detail Link is below, enjoy,
Jay

https://vintagercfiles.com/Files/Rand/S ... s_rev2.pdf
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Wayne_H
Posts: 655
Joined: 17 Feb 2018, 05:26
Location: Wellington, NZ
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Re: Galloping Ghost Rand actuator summay

Post by Wayne_H »

Thanks Jay and Tom,

A terrific reference document & an interesting read ;)
Cheers,

Wayne
Once a Retrobate, always a Retrobate............ ;)
Tobe
Posts: 444
Joined: 16 Feb 2018, 06:19
Location: Varberg or Stockholm, Sweden

Re: Galloping Ghost Rand actuator summay

Post by Tobe »

I have included a couple of pictures taken this afternoon as I tested Phil's nRF24 lockdown project with a calibrated laboratory Spectrum Analyzer.
In the code only channels between 1-80 have ben used

/************* Radio config - make it unique! **********************************/
const byte pipeOut[] = "xxxxx"; // last 5 digits of your phone number is sufficiently unique in our small group
const byte mychannels[] = {5, 80, 10, 75, 15, 70, 20, 65, 25, 60, 30, 55, 35, 50, 40, 1}; // choose 16 FHSS hopping channels
/*******************************************************************************/

which should put the system within the legal limits for most countries, 2,400 GHz - 2,483 GHz, but not all so if you go for the project you have to look up the limits for your region.
You will notice from this pictures looking at the marker 1 & 2 that the system is clearly within the limits.
You will also see the output is 19,74 dBm which is slightly less then 100mW
Marker 2 shows a frequency of 2,401 GHz, channel 1
Marker 2 shows a frequency of 2,401 GHz, channel 1
Attachments
Marker 1 shows a frequency of 2,480 GHz, channel 80
Marker 1 shows a frequency of 2,480 GHz, channel 80
Pchristy
Posts: 290
Joined: 16 Feb 2018, 13:57
Location: South Devon, UK

Re: Galloping Ghost Rand actuator summay

Post by Pchristy »

Just to clarify: The legal output in the UK is 100mW ERP. The antennas we usually use on our transmitters have a gain of 2dB, so the output measured at the Tx terminals should be 18dBm (60mW), not 20dBm (100mW). (OK, I'm nit picking! ;) )

I did actually measure mine on an RF meter. I forget what the answer was, but I'm pretty sure it was close to 18dBm. I'll re-check tomorrow, when I have a bit more time...

--
Pete
Tobe
Posts: 444
Joined: 16 Feb 2018, 06:19
Location: Varberg or Stockholm, Sweden

Re: Galloping Ghost Rand actuator summay

Post by Tobe »

The nRF2401 module is quite advanced and has many options.
The difference in PWR level was the reason Spectrum had to make a EU version, so you have to replace RF24_PA_MAX with RF24_PA_HIGH to follow EU rules.
As for the range of "usable" channels varies in different regions so do the PWR output so this has to be also properly set in the code:

Concerning the power output if you go in the Tx-sketch you will find this section:



// Tx config
radio.begin(); delayMicroseconds(500);
radio.openWritingPipe(pipeOut); delayMicroseconds(500);
radio.setAutoAck(false); delayMicroseconds(500);
radio.setDataRate(RF24_250KBPS); delayMicroseconds(500);
radio.setPALevel(RF24_PA_MAX); delayMicroseconds(500); // Set here the power level in accordance with your regions rules_RF24_PA_MIN, RF24_PA_LOW, RF24_PA_HIGH - EU power and RF24_PA_MAX - US power
radio.setChannel(mychannels[0]); delayMicroseconds(500);
radio.stopListening(); // transmit mode


I would also recommend when on the bench to have it set to RF24_PA_LOW
Pchristy
Posts: 290
Joined: 16 Feb 2018, 13:57
Location: South Devon, UK

Re: Galloping Ghost Rand actuator summay

Post by Pchristy »

Just checked mine on the power meter this morning, and its flickering between 18.9 1nd 19dBm (around 79 mW). From memory, the regulations allow a 1dB margin of error, so as it stands, its in spec - just! ;)

I'll have a look at the sketch over the week-end and see what happens with a "tweak"!

--
Pete
Pchristy
Posts: 290
Joined: 16 Feb 2018, 13:57
Location: South Devon, UK

Re: Galloping Ghost Rand actuator summay

Post by Pchristy »

I had a hard disk drive crash on my workshop computer a week or so back, and thought I'd managed to salvage everything off it. However, one of the Arduino libraries must have got corrupted, because it kept throwing up errors when I tried to compile the revised sketch. Got it sorted eventually, set the power to "HIGH" rather than "MAX", and the output is now TA!DA! 18.6dBm! A total reduction of about 0.3/4 dBm!

Hardly worth the effort, but a useful exercise!

Remind me not to be so fussy in future....!

:lol:

--
Pete
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