It's a good idea to start with OrangeRX, and then go the DIY road once you're up to speed with the system.

Originally Posted by flipflap

It's a good idea to start with OrangeRX, and then go the DIY road once you're up to speed with the system.

Thanks for your advice!

Did you already test the OrangeRX with Bluetooth?

hello Ben
I use 20 cm RG -316 for connect RF output to my diy dipole antenna,so far, each piece of dipole is 16.2 cm(solid copper ,1.4 Dia) , but I notice that the velocity factor of RG-316 is 0.79 that lead to decrease each length to 13.5 cm, am I right ? or there are any things that I don't know?

[(298 *10^6)/433*10^6]*(1/4)*0.79=13.5cm

Originally Posted by babak_ea

or there are any things that I don't know?

There are many things that we don't know, if you're talking about universe and life in general.

But for your antenna, the length of the coax cable has no importance, same for its velocity factor : a coax cable is just a waveguide, its role is to transport the signal to the antenna, even if it's far away. As long as the cable has a characteristic impedance of 50 ohms, which corresponds to the output impedance of the transmitter, and ideally to the impedance of the antenna, everything is fine.

This is a little simplified, as you know that a dipole has not a 50 ohms impedance, and that a coax cable isn't balanced so we should use a balun but let's start with a simple view.

The length of the cable will just make the signal reach the antenna a few nanoseconds sooner or later, but that's all. It won't impact the resonance frequency of the antenna.

Now the velocity factor is important for the antenna itself : as the electricity travels a little slower in copper than in empty space, we have to make the antenna a little smaller that the theoretical calculation in empty space.

To simplify your life I made a dipole antenna ruler that takes this into account : http://www.itluxembourg.lu/site/yagi...s_for_TX_or_RX

You'll see that for example for 432MHz the practical length to have resonnance is 15.38 cm

The best advice however is to buy an antenna analyzer, there are some cheap ones around, so you can see exactly how your antenna performs, and its central frequency.

Originally Posted by WimNL

Thanks for your advice!

Did you already test the OrangeRX with Bluetooth?

I saw your first post before you edited it, very funny but true

Regarding the OrangeRX with BT, I made some tests here : http://www.itluxembourg.lu/site/oran...ith-bluetooth/

But my atmega programmer seems to be broken so I wasn't able to test effectively the RX module, which has no bootloader.

It should work but its pinout is different from the ORX module, at least for the RSSI/PWM pins. If many other pins are different it could require changes to the code.

I wouldn't recommend using these modules (well, I mean the RX especially) for the moment.

Originally Posted by flipflap

There are many things that we don't know, if you're talking about universe and life in general.

But for your antenna, the length of the coax cable has no importance, same for its velocity factor : a coax cable is just a waveguide, its role is to transport the signal to the antenna, even if it's far away. As long as the cable has a characteristic impedance of 50 ohms, which corresponds to the output impedance of the transmitter, and ideally to the impedance of the antenna, everything is fine.

This is a little simplified, as you know that a dipole has not a 50 ohms impedance, and that a coax cable isn't balanced so we should use a balun but let's start with a simple view.

The length of the cable will just make the signal reach the antenna a few nanoseconds sooner or later, but that's all. It won't impact the resonance frequency of the antenna.

Now the velocity factor is important for the antenna itself : as the electricity travels a little slower in copper than in empty space, we have to make the antenna a little smaller that the theoretical calculation in empty space.

To simplify your life I made a dipole antenna ruler that takes this into account : http://www.itluxembourg.lu/site/yagi...s_for_TX_or_RX

You'll see that for example for 432MHz the practical length to have resonnance is 15.38 cm

The best advice however is to buy an antenna analyzer, there are some cheap ones around, so you can see exactly how your antenna performs, and its central frequency.

Thank's for your perfect answer.
your dipole antenna ruler based on VF=0.89, what's your antenna elements?(copper?)

so, then the radiating elements are made from copper wire , the velocity factor is around 0.95 , each elements for 433 MHz is about 16.3 cm .

For copper yes but I used these wire that look more like iron, often used for breadboards. Then measured the frequency for many length and then made the table.

Not sure about the exact wire material.

flipflap can you please advise? are RFM22 and 23BP fully compatible in terms of pinouts and FW usage, and the only difference is the length?
Thank you!

i want to say again , With dipole anten for 433mhz , it so long

i wonder : Modul rfm23bp also have 2 version 868 and 915 mhz . So i do not know any a test about both ? i think we will have anten by 1/2 version 433mhz , right ?

Originally Posted by shuricus

flipflap can you please advise? are RFM22 and 23BP fully compatible in terms of pinouts and FW usage, and the only difference is the length?
Thank you!

Absolutely, and in the beginnings, when HK had only a 100mW module and no 1W module, I made a thread about how to replace the RFM22B by a RFM23BP :

https://www.rcgroups.com/forums/show...p-instructions

Originally Posted by happy rc

i want to say again , With dipole anten for 433mhz , it so long

i wonder : Modul rfm23bp also have 2 version 868 and 915 mhz . So i do not know any a test about both ? i think we will have anten by 1/2 version 433mhz , right ?

yes, and I think openlrsng has a version for 868MHz

I working with two version 1.06 and 2.xx (diy pro mini) for long time, unfortunately I Have not measurement device but I feel the ver 1.06 has about 20 percentage more RF power output and more range (based on RSSI,analog for 1.06 and servo signal for 2.xx because I use pixhawk) ,Of course supply voltage of 1.06 can increase to 5.2 v and in 2.xx had to decrease 4.9 for avoiding damage RFM23Bp .
is this difference only related to supply voltage? or has any other reason?

The RSSI is measured in a different way on 1.06 and on 2.X, they aren't directly comparable. If you're using a power meter you should find the same power for both of them.

This is explained here : http://www.itluxembourg.lu/site/ultimate-lrs-rssi/

Originally Posted by flipflap

The RSSI is measured in a different way on 1.06 and on 2.X, they aren't directly comparable. If you're using a power meter you should find the same power for both of them.

This is explained here : http://www.itluxembourg.lu/site/ultimate-lrs-rssi/

are you running ULRS?

I am getting new hardware (Wolfblox) soon and am still thinking about URLS...

Originally Posted by flipflap

yes, and I think openlrsng has a version for 868MHz

868MHz is perfect for EU if I remember right... right?

Originally Posted by JulianGoesPro

are you running ULRS?

Well... yes I do.