RedMarsBlueMoon
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Antenna connector for the next Pi!?

Sun Nov 15, 2020 5:28 pm

Hello,
I built a enclosure out of wood ( a small arcade cabinet ) for my son that can log in to a spotify only account using Chromium.

This works great but we do get frequent breaks in the music for one up to maybe three seconds maybe once every one or two minutes.

Of course this is distracting so i started looking into extending the existing antenna but that turned out to be difficult if you dont have soldering experience.

We dont want to add a usb dongle wifi antenna as we'd like to keep the ports availabe.

Could i suggest that for the next iteration of the Pi that you consider having one of those little plugs that one can attach a longer antenna to?

Cheers
Fred

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Re: Antenna connector for the next Pi!?

Sun Nov 15, 2020 5:45 pm

RedMarsBlueMoon wrote:
Sun Nov 15, 2020 5:28 pm
Hello,
I built a enclosure out of wood ( a small arcade cabinet ) for my son that can log in to a spotify only account using Chromium.

This works great but we do get frequent breaks in the music for one up to maybe three seconds maybe once every one or two minutes.

Of course this is distracting so i started looking into extending the existing antenna but that turned out to be difficult if you dont have soldering experience.

We dont want to add a usb dongle wifi antenna as we'd like to keep the ports availabe.

Could i suggest that for the next iteration of the Pi that you consider having one of those little plugs that one can attach a longer antenna to?

Cheers
Fred

The CM4 I/O Board has that feature:

https://youtu.be/yiHgmNBOzkc

https://www.raspberrypi.org/blog/design ... -module-4/
The information is out there....you just have to let it in.

My other Linux machines are a ChromeBox & Intel CoreDuo Desktop

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Imperf3kt
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Re: Antenna connector for the next Pi!?

Sun Nov 15, 2020 8:52 pm

Wood should not hinder a wifi signal.

Maybe just drill a hole that doesn't quite go all the way through the enclosure from the inside so the sidewall is thinner near the wifi antenna.
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RedMarsBlueMoon
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Re: Antenna connector for the next Pi!?

Sun Nov 15, 2020 9:02 pm

Exactly that's why I mentioned it was made of wood.
There's also a dry wall inbetween but the router is just leaning up on the other side of that wall. (no stone/concrete).

Good spot about the compute module! They must be thinking along those lines then.

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davidcoton
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Re: Antenna connector for the next Pi!?

Sun Nov 15, 2020 10:45 pm

RedMarsBlueMoon wrote:
Sun Nov 15, 2020 9:02 pm
Exactly that's why I mentioned it was made of wood.
There's also a dry wall inbetween but the router is just leaning up on the other side of that wall. (no stone/concrete).

Good spot about the compute module! They must be thinking along those lines then.
Does the drywall have foil-lined insulation? That can cause havoc with WiFi.

The problem with a socket for the WiFi antenna is regulatory approval. Approval is only granted for the type of antenna submitted for test. Users may be tempted to change antennas, thus violating the approval (and hence operating illegally in many jurisdictions).
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hippy
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Re: Antenna connector for the next Pi!?

Mon Nov 16, 2020 4:09 pm

RedMarsBlueMoon wrote:
Sun Nov 15, 2020 5:28 pm
This works great but we do get frequent breaks in the music for one up to maybe three seconds maybe once every one or two minutes.
Are you sure it is actually an issue arising from not having an external antenna, and not something else ?

Dragontail281
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Re: Antenna connector for the next Pi!?

Mon Nov 16, 2020 4:51 pm

I agree it may be something else. I have a PI0W in my garage running MotionEyeOS and it stays connected just fine. The signal is going through about 3 walls, then about 150 feet away, outside, then through another wall.
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AaronD
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Re: Antenna connector for the next Pi!?

Mon Nov 16, 2020 5:02 pm

Wood might also be a problem for WiFi, depending on the water content.

The 2.4GHz band is available for consumer stuff, including WiFi, Bluetooth, etc., because water resonates at that frequency, and so microwave ovens use it to heat the water in food. Given a bunch of cheaply made appliances, it can't be guaranteed that it doesn't "leak" and play havoc with other stuff. So nothing critical will ever be there, which makes it open for consumer stuff. The skin depth for 2.4G in water is just a handful of millimeters, beyond which there is no appreciable signal.

So, if your wood has some water in it, that'll affect the WiFi.

Heater
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Re: Antenna connector for the next Pi!?

Mon Nov 16, 2020 5:02 pm

Dragontail281 wrote:
Mon Nov 16, 2020 4:51 pm
I agree it may be something else. I have a PI0W in my garage running MotionEyeOS and it stays connected just fine. The signal is going through about 3 walls, then about 150 feet away, outside, then through another wall.
On the other hand, in my small apartment if I put a Pi outside on my balcony, all of 10 meters away from my access point indoors, connectivity is very poor. Speed is low, drops out all the time. Despite the fact I can see the access point from the Pi location through the windows.

I can only imagine it is because of the metallic IR reflective coating on the windows. Great for stopping heat from escaping in the winter and preventing the place overheating in the direct sun in the summer. Plays havoc with WiFi and mobile phone signals.
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RedMarsBlueMoon
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Re: Antenna connector for the next Pi!?

Mon Nov 16, 2020 6:12 pm

I can stream youtube and spotify to my iphone one more room further away from the router so I wouldn't want to pry the blame away from the RPi. :)

EDIT: Maybe if it is too hard to get approval for an antenna 'jack' the onboard antenna just needs improving? My iphone has those plastic bands with the antenna running behind both at the top and the bottom. Maybe the pi could use something like that?

hippy
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Re: Antenna connector for the next Pi!?

Mon Nov 16, 2020 7:48 pm

RedMarsBlueMoon wrote:
Mon Nov 16, 2020 6:12 pm
Maybe if it is too hard to get approval for an antenna 'jack' the onboard antenna just needs improving?
It appears the radio module on the Pi 4B and and Pi 400 is approved in its own right which would seem to offer more likelihood of Pi's arriving with an external antenna option in the future.

As to the on-board PCB antenna I have found it absolutely fine in my experience as limited as it is. But I have also seen less than favourable comments made about it.

That it's not working well for some doesn't mean it's not working well for others. Without identifying what the root issue is it's hard to say that it's a an issue of on-board antenna.

Dragontail281
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Re: Antenna connector for the next Pi!?

Mon Nov 16, 2020 8:59 pm

Heater wrote:
Mon Nov 16, 2020 5:02 pm
Dragontail281 wrote:
Mon Nov 16, 2020 4:51 pm
I agree it may be something else. I have a PI0W in my garage running MotionEyeOS and it stays connected just fine. The signal is going through about 3 walls, then about 150 feet away, outside, then through another wall.
On the other hand, in my small apartment if I put a Pi outside on my balcony, all of 10 meters away from my access point indoors, connectivity is very poor. Speed is low, drops out all the time. Despite the fact I can see the access point from the Pi location through the windows.

I can only imagine it is because of the metallic IR reflective coating on the windows. Great for stopping heat from escaping in the winter and preventing the place overheating in the direct sun in the summer. Plays havoc with WiFi and mobile phone signals.
With it being an apartment, more than likely you exterior walls are concrete/block, which will block signal too.
RPI3B+ - Raspberry Pi OS -general "playing" and/or RetroPi
RPI0W#1 - MotionEyeOS - yard surveillance
RPI0W#2 - Driveway gate monitor - coming soon
RPI0W#3 - ?????

W. H. Heydt
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Re: Antenna connector for the next Pi!?

Mon Nov 16, 2020 9:18 pm

Dragontail281 wrote:
Mon Nov 16, 2020 8:59 pm
Heater wrote:
Mon Nov 16, 2020 5:02 pm
Dragontail281 wrote:
Mon Nov 16, 2020 4:51 pm
I agree it may be something else. I have a PI0W in my garage running MotionEyeOS and it stays connected just fine. The signal is going through about 3 walls, then about 150 feet away, outside, then through another wall.
On the other hand, in my small apartment if I put a Pi outside on my balcony, all of 10 meters away from my access point indoors, connectivity is very poor. Speed is low, drops out all the time. Despite the fact I can see the access point from the Pi location through the windows.

I can only imagine it is because of the metallic IR reflective coating on the windows. Great for stopping heat from escaping in the winter and preventing the place overheating in the direct sun in the summer. Plays havoc with WiFi and mobile phone signals.
With it being an apartment, more than likely you exterior walls are concrete/block, which will block signal too.
Construction techniques vary considerably by region. Brick, stone, adobe, and concrete block are very much DISfavored in California because all of them are--unless done in very specific ways--classed as "unreinforced masonry" and perform very poorly in earthquakes (aka very prone to falling down and killing people), while wood frame, if done right (sheer walls and foundation bolts), stands up amazingly well.

Brick is very common--and favored--in the US midwest, e.g. Chicago, because it's fire resistant. Concrete block is--or was, haven't been through in many years--Salt Lake City, which is a bad idea because of the near by Wasatch Fault.

W. H. Heydt
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Re: Antenna connector for the next Pi!?

Mon Nov 16, 2020 9:25 pm

RedMarsBlueMoon wrote:
Mon Nov 16, 2020 6:12 pm
I can stream youtube and spotify to my iphone one more room further away from the router so I wouldn't want to pry the blame away from the RPi. :)

EDIT: Maybe if it is too hard to get approval for an antenna 'jack' the onboard antenna just needs improving? My iphone has those plastic bands with the antenna running behind both at the top and the bottom. Maybe the pi could use something like that?
It requires specific--and expensive--testing for each and every model of antenna that winds up as part of the approval. Hence, for the CM4, there is *one* approved external antenna. Use anything else and you're either running a--definitionally--out of compliance device, or you have to go through the full approval testing process for your chosen antenna.

Most likely the biggest problem would be people buying random antennas, connecting them to Pis and then having regulatory bodies landing on the RPT with both feet for selling an untested and--probably--out of compliance device. Replying that users aren't using the one tested, compliant antenna isn't too likely to get them off the hook.

I suspect the only way around this would be use a unique, and generally unobtainable, antenna connector so that the *only* antenna that can be connected is the official--tested--one. Hard to do that with all the hardware sources out there and people who know how to use a soldering iron.

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Re: Antenna connector for the next Pi!?

Mon Nov 16, 2020 9:34 pm

AaronD wrote:
Mon Nov 16, 2020 5:02 pm
The 2.4GHz band is available for consumer stuff, including WiFi, Bluetooth, etc., because water resonates at that frequency, and so microwave ovens use it to heat the water in food. Given a bunch of cheaply made appliances, it can't be guaranteed that it doesn't "leak" and play havoc with other stuff. So nothing critical will ever be there, which makes it open for consumer stuff. The skin depth for 2.4G in water is just a handful of millimeters, beyond which there is no appreciable signal.

So, if your wood has some water in it, that'll affect the WiFi.
A minor "picky" correction - just to expose a a very common myth.

The 2.4GHz frequency isn't a specific water absorption frequency, they don't start until a much higher frequency. 2.4Ghz was a just a convenient frequency for cheap but efficient magnetrons. Most frequencies are absorbed by water in a non-resonant manner.

But as you say, because of microwave ovens, wifi was given as a freebie around that frequency as it was considered it would be unreliable and unmarketable for commercial use..

Edit: Spell guesser got me good .... abortion/absorption
Last edited by pidd on Tue Nov 17, 2020 1:37 am, edited 1 time in total.

RedMarsBlueMoon
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Re: Antenna connector for the next Pi!?

Mon Nov 16, 2020 10:08 pm

Just to make it clear my building does not have 'hard' materials for walls other than the underground garage. That goes for inside and outside.

The water levels in the wood I imagine to be negligible, and if you think they aren't then every building in the world have similar amount of water in the wood.

I did explain that my iphone is doing fine with both audio and video with one additional wall between itself and the router. And the youtube app on the iphone is really crap.

I generally agree with @hippy that it's possible that its something wrong with the software. Chromium or the way Spotify runs on chromium and that should be looked into more. I don't know how I could diagnose that?

Is there a tool that just measures wifi reception from a router?

Guys, I love my Raspberry Pies as much as you do but that doesn't mean that everything is always the fault of something else.

Heater
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Re: Antenna connector for the next Pi!?

Mon Nov 16, 2020 11:59 pm

Dragontail281 wrote:
Mon Nov 16, 2020 8:59 pm
With it being an apartment, more than likely you exterior walls are concrete/block, which will block signal too.
Like I said, I have clear line of sight between where I tried the Pi outside and the WiFi router inside. This building is indeed concrete/block but between me and my balcony is almost entirely glass. Of course being Finland there are three layers of glazing in there. About the only device that can use my WiFi out there is a Mikrotick router board, in the 5 band, with a giant antenna on it.

The IR reflective glazing used in new buildings around here has caused people to have very poor mobile phone connectivity as well. Luckily not so here.
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AaronD
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Re: Antenna connector for the next Pi!?

Tue Nov 17, 2020 1:01 am

RedMarsBlueMoon wrote:
Mon Nov 16, 2020 10:08 pm
The water levels in the wood I imagine to be negligible, and if you think they aren't then every building in the world have similar amount of water in the wood.
The water content varies based on ambient conditions. Pretty much all (serious) woodworkers know that and allow for their work to expand, contract, and move around as the weather changes. That movement is driven by the wood absorbing and releasing water as humidity.
pidd wrote:
Mon Nov 16, 2020 9:34 pm
A minor "picky" correction - just to expose a a very common myth.

The 2.4GHz frequency isn't a specific water abortion frequency, they don't start until a much higher frequency. 2.4Ghz was a just a convenient frequency for cheap but efficient magnetrons. Most frequencies are absorbed by water in a non-resonant manner.
Also a good point. I hadn't completely considered that.

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Re: Antenna connector for the next Pi!?

Tue Nov 17, 2020 1:13 am

AaronD wrote:
Tue Nov 17, 2020 1:01 am
The water content varies based on ambient conditions. Pretty much all (serious) woodworkers know that and allow for their work to expand, contract, and move around as the weather changes. That movement is driven by the wood absorbing and releasing water as humidity.
Either that or a really serious finish with multiple coats of spar varnish.

AaronD
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Re: Antenna connector for the next Pi!?

Tue Nov 17, 2020 1:28 am

W. H. Heydt wrote:
Tue Nov 17, 2020 1:13 am
AaronD wrote:
Tue Nov 17, 2020 1:01 am
The water content varies based on ambient conditions. Pretty much all (serious) woodworkers know that and allow for their work to expand, contract, and move around as the weather changes. That movement is driven by the wood absorbing and releasing water as humidity.
Either that or a really serious finish with multiple coats of spar varnish.
That works too, but the OP hasn't mentioned it. Also, it doesn't take the moisture out, but simply seals it so that it doesn't change.
Last edited by AaronD on Tue Nov 17, 2020 4:44 am, edited 1 time in total.

trejan
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Re: Antenna connector for the next Pi!?

Tue Nov 17, 2020 1:49 am

RedMarsBlueMoon wrote:
Mon Nov 16, 2020 10:08 pm
Is there a tool that just measures wifi reception from a router?
Run a continuous ping with the target as the Pi. If the sound drops out and there aren't any missing pings then its not the WiFi.

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Re: Antenna connector for the next Pi!?

Tue Nov 17, 2020 4:41 am

ping and traceroute (mtr is a snazzy version of traceroute) will definitely help here. mtr will show packets lost, in real time.

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Re: Antenna connector for the next Pi!?

Tue Nov 17, 2020 5:16 am

AaronD wrote:
Tue Nov 17, 2020 1:28 am
W. H. Heydt wrote:
Tue Nov 17, 2020 1:13 am
AaronD wrote:
Tue Nov 17, 2020 1:01 am
The water content varies based on ambient conditions. Pretty much all (serious) woodworkers know that and allow for their work to expand, contract, and move around as the weather changes. That movement is driven by the wood absorbing and releasing water as humidity.
Either that or a really serious finish with multiple coats of spar varnish.
That works too, but the OP hasn't mentioned it. Also, it doesn't take the moisture out, but simply seals it so that it doesn't change.
My day job involves high specific moisture content wood. I could try to test wifi reception under various conditions if there's enough interest.
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hippy
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Re: Antenna connector for the next Pi!?

Tue Nov 17, 2020 11:46 am

W. H. Heydt wrote:
Mon Nov 16, 2020 9:25 pm
Most likely the biggest problem would be people buying random antennas, connecting them to Pis and then having regulatory bodies landing on the RPT with both feet for selling an untested and--probably--out of compliance device. Replying that users aren't using the one tested, compliant antenna isn't too likely to get them off the hook.
I can't see that happening. The principle that a manufacturer is not responsible for unlawful acts undertaken by the users of its products is well established.

It seems to me the only justified complaint could be of encouraging unlawful acts by not including a certified antenna with the product which leads to some users choosing something other than the certified antenna they sell as an optional extra.

If that were a potential problem the mitigation would be to include an antenna with every product which has an antenna connector, and not have the antenna connector when a product doesn't include an antenna.

I would also assume they had considered and discounted this exact issue when they decided to sell the CM4 with an antenna connector and sell the certified antenna separately.

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davidcoton
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Re: Antenna connector for the next Pi!?

Tue Nov 17, 2020 11:59 am

hippy wrote:
Tue Nov 17, 2020 11:46 am
I would also assume they had considered and discounted this exact issue when they decided to sell the CM4 with an antenna connector and sell the certified antenna separately.
Consider also that many products based on the CM4 will need to be re-certified in any case, at least AIUI.
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