Micro controllers with UHF transceivers?

On Thu, 25 Oct 2007 15:46:40 -0700, Joerg
<notthisjoergsch@removethispacbell.net> wrote:

>Paul Keinanen wrote:

>> At least in Europe, the available bands would be 2.45 GHz, 433 MHz, 27
>> MHz and 13.56 MHz. Please note that in Europe, you might encounter
>> 1-100 W amateur radio transmissions at the same or very close
>> frequencies in the 433 MHz and 2.45 MHz band, so a good front end
>> selectivity would be required. On 27 MHz 5 W CB transmissions could
>> occur close to your frequencies and especially during the sunspot
>> maximum, the HF frequencies may have strong signals from sources
>> 1000-2000 km away. Also the 13.56 MHz band may have strong RFID
>> signals.
>> 
>
>There is also 40.7MHz but I've got to brush up what's available in 
>Europe and other areas. That band works really well for longer ranges as 
>long as your data volume is low.

I forgot that ISM band, which is also used by model airplane control
etc. 

The allowed SRD power levels are in he order of 100-500 mW. This band
is quite during the sun spot minimum, but at sun spot maximum
especially in the summer, you can get noise and interference from far
away.
 

>> While the omnidirectional receiver antenna capture area is small on
>> 2.45 GHz, this is not a problem on HF/VHF frequencies, in which a
>> miniature receiver antenna is capable of receiving the band noise, but
>> at to lower frequencies, the problem is the transmitter antenna
>> efficiency. When the antenna dimension goes below about 1/10
>> wavelength, the radiation resistance drops quite low and the
>> transmitter antenna efficiency is quite low.
>> 
>
>Depends on the power. We have two FRS radios (460MHz) with very short 
>stubs. Theoretically they should be about 15cm long but they are maybe 
>about 2cm. 

Sounds like a helical spiral coated with rubber. Not very efficient
and the resonance will shift very easily in proximity of foreign
objects such as the human body.

>Yet I can talk to my wife when she is checking on a neighbor 
>half a mile away, crystal clear voice signal. Out here that is necessary 
>because we have a lot of wild animals running around and a call process 
>on a cell phone takes too long when a bear barges around the corner.

So you live in the middle of the woods. In such environment you have
very little reflections and the vegetation losses can be quite high at
higher frequencies. The background noise levels are low.

Other people living in a different environment might have a lot of
good reflections from nearby buildings and the background noise level
can be quite high (from distant radio sources and interference from
various electric appliances).

Unless you are designing a product for a similar environment as you
are living in, you should check for the performance of devices in
various frequency bands in all kinds of environment.
   
>>>> You said that the range was too short on 2.45 GHz. What kind of
>>>> propagation environment do you have ? Free space, lot of thick trees,
>>>> indoor or what ?  
>>> All of the above, usually comms between a pod inside the house to 
>>> equipment outside. I guess our house would be the worst case, woodframe 
>>> construction with aluminum backed insulation inside the walls.
>> 
>> Unless your windows are coated with some heat reflecting film, the UHF
>> signal should easily pass through the windows.
>> 
>
>Well, it should but you can't ask it to do a 75 degree turn after 
>passing the window ;-)

At very low frequencies, diffraction takes care of this. In urban
areas, reflections from the house on the other side of the street to
an equipment below your window, will usually enable communication even
at higher frequencies.


>> When using the license free frequency bands with legal power levels,
>> one should expect 10-100 m reliable communication in typical
>> conditions. 
>
>100m would be fine, 10m would not.

In urban areas, in which the number of license free devices steadily
increase, the range of existing systems is going to decrease as the
interference is going up, so don't make too much assumptions of the
typical range based on your tests in your very quiet place.

Paul

Paul Keinanen wrote:
> On Thu, 25 Oct 2007 15:46:40 -0700, Joerg
> <notthisjoergsch@removethispacbell.net> wrote:
> 
>> Paul Keinanen wrote:
> 
>>> At least in Europe, the available bands would be 2.45 GHz, 433 MHz, 27
>>> MHz and 13.56 MHz. Please note that in Europe, you might encounter
>>> 1-100 W amateur radio transmissions at the same or very close
>>> frequencies in the 433 MHz and 2.45 MHz band, so a good front end
>>> selectivity would be required. On 27 MHz 5 W CB transmissions could
>>> occur close to your frequencies and especially during the sunspot
>>> maximum, the HF frequencies may have strong signals from sources
>>> 1000-2000 km away. Also the 13.56 MHz band may have strong RFID
>>> signals.
>>>
>> There is also 40.7MHz but I've got to brush up what's available in 
>> Europe and other areas. That band works really well for longer ranges as 
>> long as your data volume is low.
> 
> I forgot that ISM band, which is also used by model airplane control
> etc. 
> 

Do you guys use that, too?


> The allowed SRD power levels are in he order of 100-500 mW. This band
> is quite during the sun spot minimum, but at sun spot maximum
> especially in the summer, you can get noise and interference from far
> away.
>  

500mW is a whole lotta power, you can get nearly all the range you want 
with that. But, no combined chips :-(

> 
>>> While the omnidirectional receiver antenna capture area is small on
>>> 2.45 GHz, this is not a problem on HF/VHF frequencies, in which a
>>> miniature receiver antenna is capable of receiving the band noise, but
>>> at to lower frequencies, the problem is the transmitter antenna
>>> efficiency. When the antenna dimension goes below about 1/10
>>> wavelength, the radiation resistance drops quite low and the
>>> transmitter antenna efficiency is quite low.
>>>
>> Depends on the power. We have two FRS radios (460MHz) with very short 
>> stubs. Theoretically they should be about 15cm long but they are maybe 
>> about 2cm. 
> 
> Sounds like a helical spiral coated with rubber. Not very efficient
> and the resonance will shift very easily in proximity of foreign
> objects such as the human body.
> 

But it simply works!


>> Yet I can talk to my wife when she is checking on a neighbor 
>> half a mile away, crystal clear voice signal. Out here that is necessary 
>> because we have a lot of wild animals running around and a call process 
>> on a cell phone takes too long when a bear barges around the corner.
> 
> So you live in the middle of the woods. In such environment you have
> very little reflections and the vegetation losses can be quite high at
> higher frequencies. The background noise levels are low.
> 
> Other people living in a different environment might have a lot of
> good reflections from nearby buildings and the background noise level
> can be quite high (from distant radio sources and interference from
> various electric appliances).
> 
> Unless you are designing a product for a similar environment as you
> are living in, you should check for the performance of devices in
> various frequency bands in all kinds of environment.
>    

Oh, we live in an RF-crowded environment. Tons of multipath reflections, 
a local airport runway almost next to the house (you can taxi your 
aircraft right up to some of the houses here), lots of TV, radio and 
communication towers on the next ridge because we are on the last 
mountainous outcropping before the Sacramento plane. IOW this is RF 
hell, as evidenced by the fact that the usual TV set falls off the 
rocker without a serious set of custom notch filters in front of it.


>>>>> You said that the range was too short on 2.45 GHz. What kind of
>>>>> propagation environment do you have ? Free space, lot of thick trees,
>>>>> indoor or what ?  
>>>> All of the above, usually comms between a pod inside the house to 
>>>> equipment outside. I guess our house would be the worst case, woodframe 
>>>> construction with aluminum backed insulation inside the walls.
>>> Unless your windows are coated with some heat reflecting film, the UHF
>>> signal should easily pass through the windows.
>>>
>> Well, it should but you can't ask it to do a 75 degree turn after 
>> passing the window ;-)
> 
> At very low frequencies, diffraction takes care of this. In urban
> areas, reflections from the house on the other side of the street to
> an equipment below your window, will usually enable communication even
> at higher frequencies.
> 
> 
>>> When using the license free frequency bands with legal power levels,
>>> one should expect 10-100 m reliable communication in typical
>>> conditions. 
>> 100m would be fine, 10m would not.
> 
> In urban areas, in which the number of license free devices steadily
> increase, the range of existing systems is going to decrease as the
> interference is going up, so don't make too much assumptions of the
> typical range based on your tests in your very quiet place.
> 

We'll test it alright. But as I said this ain't a quite area at all.

-- 
Regards, Joerg

http://www.analogconsultants.com/

On 2007-10-26, Paul Keinanen <keinanen@sci.fi> wrote:
> On Thu, 25 Oct 2007 15:46:40 -0700, Joerg
><notthisjoergsch@removethispacbell.net> wrote:
>>
>>There is also 40.7MHz but I've got to brush up what's available in 
>>Europe and other areas. That band works really well for longer ranges as 
>>long as your data volume is low.
>
> I forgot that ISM band, which is also used by model airplane control
> etc. 

Be careful about those bands: I don't know about other areas but
here in the UK the 35MHz and 40MHz are set aside specifically for
radio control aircraft and surface vehicles respectively.  Given
the safety implications of interference on 35MHz in particular I
don't think Ofcom would react too kindly if they heard about illegal
transmissions on those frequencies.

-- 
Andrew Smallshaw
andrews@sdf.lonestar.org

On Fri, 26 Oct 2007 08:33:11 -0700, Joerg
<notthisjoergsch@removethispacbell.net> wrote:

>Paul Keinanen wrote:
>> On Thu, 25 Oct 2007 15:46:40 -0700, Joerg
>> <notthisjoergsch@removethispacbell.net> wrote:
>> 
>>> Paul Keinanen wrote:


>>> Yet I can talk to my wife when she is checking on a neighbor 
>>> half a mile away, crystal clear voice signal. Out here that is necessary 
>>> because we have a lot of wild animals running around and a call process 
>>> on a cell phone takes too long when a bear barges around the corner.
>> 
>> So you live in the middle of the woods. In such environment you have
>> very little reflections and the vegetation losses can be quite high at
>> higher frequencies. The background noise levels are low.

>Oh, we live in an RF-crowded environment. Tons of multipath reflections, 
>a local airport runway almost next to the house (you can taxi your 
>aircraft right up to some of the houses here), lots of TV, radio and 
>communication towers on the next ridge because we are on the last 
>mountainous outcropping before the Sacramento plane. IOW this is RF 
>hell, as evidenced by the fact that the usual TV set falls off the 
>rocker without a serious set of custom notch filters in front of it.

Sorry for my misunderstanding. 

Over here, we have problems with bears and wolves mainly in rural
areas, where they scare schoolchildren and sometimes take some dogs or
sheep. It is quite rare that a bear would stray into urban areas.

Paul

Paul Keinanen wrote:
> On Fri, 26 Oct 2007 08:33:11 -0700, Joerg
> <notthisjoergsch@removethispacbell.net> wrote:
> 
>> Paul Keinanen wrote:
>>> On Thu, 25 Oct 2007 15:46:40 -0700, Joerg
>>> <notthisjoergsch@removethispacbell.net> wrote:
>>>
>>>> Paul Keinanen wrote:
> 
> 
>>>> Yet I can talk to my wife when she is checking on a neighbor 
>>>> half a mile away, crystal clear voice signal. Out here that is necessary 
>>>> because we have a lot of wild animals running around and a call process 
>>>> on a cell phone takes too long when a bear barges around the corner.
>>> So you live in the middle of the woods. In such environment you have
>>> very little reflections and the vegetation losses can be quite high at
>>> higher frequencies. The background noise levels are low.
> 
>> Oh, we live in an RF-crowded environment. Tons of multipath reflections, 
>> a local airport runway almost next to the house (you can taxi your 
>> aircraft right up to some of the houses here), lots of TV, radio and 
>> communication towers on the next ridge because we are on the last 
>> mountainous outcropping before the Sacramento plane. IOW this is RF 
>> hell, as evidenced by the fact that the usual TV set falls off the 
>> rocker without a serious set of custom notch filters in front of it.
> 
> Sorry for my misunderstanding. 
> 
> Over here, we have problems with bears and wolves mainly in rural
> areas, where they scare schoolchildren and sometimes take some dogs or
> sheep. It is quite rare that a bear would stray into urban areas.
> 

Here they do. Bears are usually quite friendly but mountain lions 
sometimes aren't.

Living together with wildlife is normal out here. For example, we have a 
fox family giving birth and raising their kits right here next to our 
house every year. The (late) first owner said that has been the case 
since when the house was built around 1970. They even don't mind out 
large dogs, probably just consider them monster-foxes.

-- 
Regards, Joerg

http://www.analogconsultants.com/

Joerg wrote:
>> Eh? Did you find your way to this page: <http://www.atmel.com/dyn/
>> products/devices.asp?family_id=651>
> Says "Directory Listing Denied" :-(

The URL was broken, need to re-join it:
<http://www.atmel.com/dyn/products/devices.asp?family_id=651>.

Is there anything with receive that reaches down to 144MHz (2 meter)
band?

Clifford Heath wrote:
> Joerg wrote:
>>> Eh? Did you find your way to this page: <http://www.atmel.com/dyn/
>>> products/devices.asp?family_id=651>
>> Says "Directory Listing Denied" :-(
> 
> The URL was broken, need to re-join it:
> <http://www.atmel.com/dyn/products/devices.asp?family_id=651>.
> 

Thanks. But same as usual, only TX with uC, not transceivers with uC.


> Is there anything with receive that reaches down to 144MHz (2 meter)
> band?


You'll have to study the data sheets in detail, see if it can be goosed 
down via another master oscillator etc. Most likely not if there are 
frequency dependent parts inside. The area below 300MHz seems to be 
strictly discrete and ASIC territory.

-- 
Regards, Joerg

http://www.analogconsultants.com/

Jim Granville no.spam@designtools.maps.co.nz posted to
sci.electronics.design:

> larwe wrote:
>> On Oct 24, 9:13 pm, Joerg <notthisjoerg...@removethispacbell.net>
>> wrote:
>> 
>> 
>>>>How about CC1110F32 from TI.
>>>
>>>Thanks, Don! How could I have missed that? I was looking at lots of
>>>CC11xx datasheets today. Five bucks is a bit highish but would work
>>>in
>> 
>> 
>> You should consider this part limited lifespan IMHO precisely
>> because of the 51 core. Remember Chipcon is now owned by TI. I
>> would say if your design horizon exceeds 3~4 years it would be
>> better not to pick this part.
> 
> That's some strange logic.
> 
> TI has had '51 devices in their USB and
> BurrBrown product lines for some time.
> 
> There is no reason to re-spin proven die, to swap-out one core,
> and put another in ?!.
> This is engineering, not fashion.
> 
> -jg

Not according to the sales critters.

larwe zwsdotcom@gmail.com posted to sci.electronics.design:

> 
>> So you mean some NEW designs are being done with MSP430 ?
> 
> Yes.
> 
>> That does not mean the existing devices are going to
>> vanish any time soon.
>> (Indeed, if Ti are smart, the new devices will be pin-compatible.)
> 
> They definitely won't based on the discussions I've had. The first
> part will be an all-singing-all-dancing part [i.e. someone's ASIC
> sold to the general market]. Other versions will follow. I'd expect
> to see early silicon at the end of next year.
> 
>> Was TI the foundry for Chipcon, or did chipcon use a more
>> conventional foundry ?
> 
> I'm not sure, didn't follow the relationship that closely.

That was some odd pasting.

Joerg notthisjoergsch@removethispacbell.net posted to
sci.electronics.design:

> Paul Keinanen wrote:
>> On Wed, 24 Oct 2007 13:34:29 -0700, Joerg
>> <notthisjoergsch@removethispacbell.net> wrote:
>> 
>>> Hello Folks,
>>>
>>> After some Google searching and perusing the sites of the usual
>>> contenders I only found one uC family that has serious on-chip RF
>>> transceiver capabilities, the Cypress CYWUSB6953 and its brethren.
>>> rfPICs and others usually only have a transmitter.
>>>
>>> Anyhow, the Cypress will only serve 2.45GHz but I need the lower
>>> UHF bands for range reasons. Is anything coming down the pike soon
>>> or will that have to remain a two-chip solution?
>> 
>> It would help if you had specified the country in which it should
>> operate. The frequency bands, the power levels and duty cycles vary
>> with country or at least with continent.
>> 
> 
> As many countries as possible. Definitely US, Canada, Europe and in
> and around the Gulf of Mexico, other cases also Asia. That leaves
> 433MHz and 2.45GHz. Or frequencies below 100MHz but there aren't any
> integrated solutions for those.
> 
> 
>> You said that the range was too short on 2.45 GHz. What kind of
>> propagation environment do you have ? Free space, lot of thick
>> trees, indoor or what ?
>> 
> 
> All of the above, usually comms between a pod inside the house to
> equipment outside. I guess our house would be the worst case,
> woodframe construction with aluminum backed insulation inside the
> walls.
> 
> 
>> In a free space environment, the capture area of an omnidirectional
>> receiver antenna at a higher frequency can get quite small, thus
>> the receiver signal will be weaker. Also a lot of wet trees will
>> attenuate the 2.45 GHz signal.
>> 
>> On the other hand, in typical indoor situations and at the streets
>> of a large city, there are going to be plenty of reflections and
>> the propagation is more or less independent of the frequency. The
>> shorter wavelength might even propagate more easily through narrow
>> slits in air conditioning ducts etc.
>> 
> 
> All I can say that around our house 2.45GHz does not work reliably
> at all. <200MHz works excellent.
> 

Now you are talking VHF instead of UHF.