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Help...I need a recommendation...Which Hope Module should I choose?????  XML
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jrkirk



Joined: 11/05/2015 08:04:51
Messages: 1
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I also posted this on the Radio Head Google Groups.
Help...I need a recommendation on Hope RFModules

I've made a custom board with a AtMega32u4 chip driving a HopeRF RFM26w 433MHz Transceiver Module. The only reason I chose the RFM26W was because it supposedly will transmit at 1,000,000 bits per second. It uses a SiliconLabs Si4463 chip. The downside is that nobody uses this module because of it's screwy API interface. In most SPI programming you have a single byte read and write of a register, a burst mode read and write of consecutive registers, and a mode to read and write to the FIFOs.

Well programming this Si4463 chip is completely new. It's as if the micro-controller group stuck their nose over in the radio side of things. It's completely screwed up...and hard to explain. That's why nobody uses this thing. If you do a Google search on RFM26W you'll only get 9 pages of results...most of it worthless.

The one post you will find is me and another guy who posted our problem on the Silicon Labs forum. We can't even get past turning the chip on, and pulling the Version Information. The trailblazers are always the ones with the arrows in their backs.
Lesson learned.

So now, what I need is a recommendation.....
I'm going to re-spin this board to accommodate a more mainstream HopeRF Module.
But, I don't know which Hope Module to choose.
Here are my requirements:
1. The radio(433Mhz) will be used in controlling radio controlled aircraft(airplanes, copters, quad-copters, etc.) The radio in the plane will need to send back telemetry...so the ground and air radio's will both have to be "full transceivers". I want to use the identical Hope Module in each.
2. I need all the range I can get, so 100millwatt (20dB) minimum both ways.
3. I need 250Kbps or more radio transmission data rate. I'll be driving the radios with SPI at 4 a meg clock.
4. I need 64 byte FIFO's minimum.
5. I'd like the ability to frequency hop.
6. I don't care about power consumption...that's not an issue.

I want something that has been pounded on by many people.
But I don't want something on the verge of obsolescence.
I want to keep things as simple as possible:

Essentially I want the code to set up the radio's frequency, set the transmission baud rate, point to the hop channel...
Then, fill the FIFO with a fixed length 64 byte message...transmit to the plane...the plane responds with a fixed length 64 byte message...
Then, the ground and plane radios both hop to the next hop channel...then repeat the transmission sequence.......
I'd like auto CRC, but I don't need reliable transmission. Bad packets(bad CRC's) will be dropped...and missed packets are not an issue.

I know Hope modules use Silicon Labs or Semtech chips.
Any thoughts on which is better?

Thanks for any recommendations,

Jim K.
lucky star



Joined: 12/05/2015 04:18:33
Messages: 1
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I don't know whether you have solved the problem, but maybe I can help you. You can contact if you still need my help. my skype is wssls16@126.com
stevech



Joined: 07/07/2014 18:07:27
Messages: 91
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OP: Have you looked at RadioHead as your protocol stack? Then choose among it's radio modules supported.
RFM69 perhaps.
Don't try to start with a bare radio and no protocol stack (such as reliable datagrams with ACKs and retransmissions - as in RadioHead).

You cannot run 1Mbps in 433MHz. Illegal and the band is too small to accommodate that channel width.
If in No. America, and some Asian, use 902-928MHz. RFM69HW for that band. Else 868MHz for the EU.
Expecting 100+Kbps net yield (not the raw bit rate) is realistic IF you can get the received signal strength high enough for a large SNR.

If this is a point to point link, you can use yagii or other antennas with 8dBi or more gain in the 915MHz area. Of practical size/cost. Far better to use antenna gain than TX power.

You need to describe the path from A to B radio sites: Distance, clear line of sight? Antenna elevations? Fresnel zone clearance desired. You can calculate the received signal strength, or I'll do it if you tell me the path details.
 
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