Rf220 , sm220

[gvoce]

TX output power, TXpwr command

[bsborden]

Snappy Power Levels

txPwr(power) ranges from 0 to 17, but your table only shows 0 thru 7 for SNAPPy Level.

[bsborden]

Snappy Power Levels

txPwr(power) ranges from 0 to 17, but your table only shows 0 thru 7 for SNAPPy Level.

[Aussie]

RF220 power levels

Greg,

Can you please clarify the power level settings for the new RF220 modules.

I have just received number of RF220 modules and with default settings (F antenna) , It appears that power output is lower than RF200 module.

Have tried changing ID70 to maximum x11 for all channels, but compared to RF200 operating next to it, signal level of RF220 is about half of the RF200?

Thanks
John

[gvoce]

How are you measuring the TX levels and have you tried using the
txPwr(power) –Set Radio TX power level command?

[Del Tapparo]

Is the RF220 a drop in replacement for the RF200? It worked fine in my "First" board, but not in my "Second" board. The second board's application uses sleep mode. Maybe it isn't waking up?

[berwyn]

FYI: There were various significant sleep improvements between firmware 2.4.35 and 2.5.3. I don't know whether that's relevant.

[gvoce]

The device would not go into sleep if you did not have the correct settings in your script for wake on interrupt so that must be correct. Only certain pins can be used for wake on interrupt so I would check those and make sure you are actually on the correct pin

[Del Tapparo]

I upgraded the firmware to SM220UF1. No help. SNAP Ref manual refers you to RF200 for pinouts, so I would assume they are identical. All of the wakeup pins worked before, but not now. ???

[gvoce]

For the RF220 you sue the SM220 platform and firmware

[Del Tapparo]

Problem solved. The platform.py and rf220.py files weren't in the directory I am using. Program now works with no modifications! Thank you for your help.

[allen.corley]

I am running two RF220UF1 modules in a transparent serial mode. One module is always on and I would like that module to detect when the 2nd module is connects to it.

[jasonharper]

There isn't really any concept of connections between modules - each individual packet is an entirely separate entity. (In other words, it's more like UDP than TCP.)

You could detect the presence of your second module by periodically sending a RPC to it, and seeing if you get a reply.

If your transparent serial data will be more or less continuous when both modules are active, another possibility would be to watch the packet count (exposed by the getStat() call), to see if any data is flowing.

[allen.corley]

Thank you jasonharper. The rpc worked nicely.

[jamos]

JayP,

What you ask is a very difficult question to answer. Everything depends on your setup and for sure which modules are being used. For example, the SM200 radios have a chip antenna on board that does not have favorable gain and they do not have a PA on board. This compared to a RF200PF1 for example that uses an integrated F antenna with a PA. That gives the SM200P81 about 12dB lower output power than the RF200PF1 (antenna patterns do matter and so at some angles the difference in gain could be more or less, this is just an average).

Given that the Atmel radios only provide 81 dB of dynamic range for RSSI. (See page 69 in the ATmega128RFA1 datasheet (my version is dated 9/14), but section 9.5.3 for details.) The Atmel will provide values down to -90dB, however it will continue to receive to about -101 or -103 dB depending on which module you have. The maximum RSSI value is around -9. These are done in 3dB steps so there isn't a lot of granularity when using RSSI.

I have to double check to see if getLQ uses the RSSI function or if it uses the Energy Detection method of the chip, the end result isn't much different really.

So to answer your question the range that you can get is higher for the RF200PD1 or RF200PF1 than for the SM200P81, but those are just 3 specific examples. It would vary more with the use of the RF220 series radio modules and can vary depending on what the receive module is and the use of antennas, extra cables, etc. because you really need to maximize the dynamic range of the receiver (the 81dB mentioned earlier).

The path loss (when assuming a gain of 1dB for both antennas, which is not exactly correct) would yield ~48dB of signal loss at 10 feet and -51dB at 15 feet only -57dB at 30 feet and finally -65dB at 75 feet.

The general formula of computing this pathloss is:

PL = 20*log10(d) + 20*log10(f) + 20*log10(4*pi/c) - Gt - Gr
d is distance in meters, f = frequency in Herz, c is speed of light, Gt and Gr in dB.

I am not sure that the gain of each antenna is 1 and certainly depending on the antennas you are using the pattern will matter greatly.

Thus the signal you can get when you are close to the antenna will determine the starting point (you mentioned receiving 18 (meaning a -18dB if this came from getLq()) from -18 to -90 is 72dB working range so you should in free space be able to work that distance.

Just remember that you are not in free space, especially if your body is near the transmit antenna and either of your antennas are near any other structure. (i.e. Earth). Typically you would need your antennas around 3feet clear of any structure (earth included), due to the effect of the fresnel zone. To realize those numbers and would need to minimize multi-path. This is obviously difficult to do in the real world so the numbers become effected by those sources making these types of measurements quite difficult.

I hope this helps.

[Jon.Wilder]

I'm about to pull the trigger on some RF220 radios but have a couple of questions -

1) Can an RF200 and RF220 talk to each other?

2) What is the approximate LOS range of the RF220UF1 (no SMA connector)?

[Jheath]

1) Can an RF200 and RF220 talk to each other?

Yes, all of the current 2.4 GHz modules from Synapse are capable of talking to one-another

(assumes they are all configured alike, which is their default configuration... same Tx mode, channel, encryption, yada yada)

2) What is the approximate LOS range of the RF220UF1 (no SMA connector)?

Using an external u.FL you can get ~3 miles (Outdoor LOS). With the on-board trace you can get upwards of 1/2 a mile (again outdoor LOS to compare apples to apples)

[michael.s]

Hello Synapse team,

Does the RF220 support any kind of wake-on-radio mode? I've been trying to figure out if this is possible but from what I can tell, it isn't an option.

Thanks.

[gvoce]

radio is off in sleep mode

[jamos]

These modules are not capable of wake on radio only wake on pin or timed.

[Jheath]

These type of radios do not have wake-on capabilities. We have evaluated these type radios, but there are trade offs that haven't tipped things over to were we have created a module.

Side note: In a mesh network, a wake-on option can get triggered more often than expected.

[ghonan2]

Re: Sporadic Response to Multicast

Hi jamos,

Thank you for getting back to me so quickly!

To answer your question about the scope picture, I added a UART print statement after the call to mcastRpc so those spikes are just "test" getting printed out by the tag (perhaps a pin toggle would've been a better choice).

Thank you for drawing attention to the sleep mode issue - I had read the relevant Atmel platform section, but neglected to check the RF220 section. I will also definitely make use of the RPC_SENT hook as you suggest. That seems like a much safer option than what I was doing.

The system I'm building is a portable equipment tracking system for a college campus. Readers will be in each classroom, and tags will be attached to each piece of tracked equipment. Right now we're just creating a proof of concept, so only two readers and between 2-4 tags will be active. I'm not sure if that's sufficient information for you to advise on network tuning parameters, but if you have anything in mind feel free to let me know.

In a college campus environment where there's a large amount of WiFi traffic I'm guessing carrier sense is a bad idea? Given what you said about noisy environments, I'm leaning towards just enabling collision detection and collision avoidance and leaving carrier sense off. Does that sound ok to you?

[gjinkerson]

How did you you get on with this issue? I seem to be having similar problems... RF220 apparently not having the same range as the RF200...

??

Answers on a postcard, please!

[gvoce]

What are you seeing in comparison to the RF200 and how are you measuring the TX output power? The SNAP reference manual has a chart that specifies the TX power for the RF220. It can be found on page 111 and 112 at this link .....

http://www.synapse-wireless.com/upl/...m-78815f3c.pdf

Also how many units are you seeing the low TX output on?