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RF Window Size
My antenna theory knowledge is a little weak so I thought you guys
might be able to help. Background: I have a shed about 50 feet away from my house that contains water pumps and similar equipment that I monitor. The shed has no windows but was built using normal stud-wall construction. I built a small device that receives information from sensors and then reports back to my PC via my home network. I have no way to run wires to the shed because there is a driveway in between, so I decided to use wi-fi. The shed had a good strong wi-fi signal inside it and everything worked well for the last 5 years. Recently, vinyl siding was added to the shed. The installers used foil coated styrofoam insulation under the siding. The shed has changed from being fairly transparent to RF to being a somewhat leaky faraday shield. The wifi module still works, but just barely. There are lots of missed messages and any interference from devices like the microwave oven in the house shut down communications. Question: I want to create an RF "window" in the shed wall. How big does it need to be to let 2400 MHz signals pass through it? A full wavelength? Half wavelength? Should it be rectangular or would a vertical slot work? Opening the shed door (a full size metal door) temporarily restores a strong signal, but I was hoping a much smaller opening would work equally well. For aesthetic reasons, I can't experiment by cutting various size holes. What's the smallest hole I can cut in the foil coated insulation and be reasonably assured it will work? Thanks, Pat |
RF Window Size
Pat wrote:
My antenna theory knowledge is a little weak so I thought you guys might be able to help. Background: I have a shed about 50 feet away from my house that contains water pumps and similar equipment that I monitor. The shed has no windows but was built using normal stud-wall construction. I built a small device that receives information from sensors and then reports back to my PC via my home network. I have no way to run wires to the shed because there is a driveway in between, so I decided to use wi-fi. The shed had a good strong wi-fi signal inside it and everything worked well for the last 5 years. Recently, vinyl siding was added to the shed. The installers used foil coated styrofoam insulation under the siding. The shed has changed from being fairly transparent to RF to being a somewhat leaky faraday shield. The wifi module still works, but just barely. There are lots of missed messages and any interference from devices like the microwave oven in the house shut down communications. Question: I want to create an RF "window" in the shed wall. How big does it need to be to let 2400 MHz signals pass through it? A full wavelength? Half wavelength? Should it be rectangular or would a vertical slot work? Opening the shed door (a full size metal door) temporarily restores a strong signal, but I was hoping a much smaller opening would work equally well. For aesthetic reasons, I can't experiment by cutting various size holes. What's the smallest hole I can cut in the foil coated insulation and be reasonably assured it will work? 4mm, to take the coax to an outside wifi aerial. If you can't find a wifi unit with an aerial socket, change this to usb cable to an outside wifi dongle. but you may then need a 12mm hole for the USB plug. -- Roger Hayter |
RF Window Size
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RF Window Size
On 3/25/2016 8:50 AM, Roger Hayter wrote:
Pat wrote: On Fri, 25 Mar 2016 12:04:11 +0000, (Roger Hayter) wrote: Pat wrote: My antenna theory knowledge is a little weak so I thought you guys might be able to help. Background: I have a shed about 50 feet away from my house that contains water pumps and similar equipment that I monitor. The shed has no windows but was built using normal stud-wall construction. I built a small device that receives information from sensors and then reports back to my PC via my home network. I have no way to run wires to the shed because there is a driveway in between, so I decided to use wi-fi. The shed had a good strong wi-fi signal inside it and everything worked well for the last 5 years. Recently, vinyl siding was added to the shed. The installers used foil coated styrofoam insulation under the siding. The shed has changed from being fairly transparent to RF to being a somewhat leaky faraday shield. The wifi module still works, but just barely. There are lots of missed messages and any interference from devices like the microwave oven in the house shut down communications. Question: I want to create an RF "window" in the shed wall. How big does it need to be to let 2400 MHz signals pass through it? A full wavelength? Half wavelength? Should it be rectangular or would a vertical slot work? Opening the shed door (a full size metal door) temporarily restores a strong signal, but I was hoping a much smaller opening would work equally well. For aesthetic reasons, I can't experiment by cutting various size holes. What's the smallest hole I can cut in the foil coated insulation and be reasonably assured it will work? 4mm, to take the coax to an outside wifi aerial. If you can't find a wifi unit with an aerial socket, change this to usb cable to an outside wifi dongle. but you may then need a 12mm hole for the USB plug. What you have suggested is my "Plan B". The wifi module I am using does not have removable antennas and the sensor box does not have USB capabilities. Thanks for responding. ...Pat I would look into how to couple an external aerial to the built-in aerial of an existing wifif module. ISTR people doing this. Altenative, how about putting a window either in the wall towards the wifi source, or. depending on the roofing material, in the roof which can sometimes be done with acrylic or polycarbonater replacement roofing elements? There's a point. If the metal was added to the walls only, you might be able to rise above that by placing the antenna at the highest point of the roof. I assume that is accessible in a shed. -- Rick |
RF Window Size
On Fri, 25 Mar 2016 07:48:23 -0400, Pat wrote:
I want to create an RF "window" in the shed wall. How big does it need to be to let 2400 MHz signals pass through it? The minimum would be a half wave slot cut through the aluminum foil. The width will vary depending on the type of antenna and its proximity to the slot. Unless you have a half wave dipole near the slot, it won't work. If you're using a patch antenna or something similar, probably a half wave by half wave square hole would be a good minimum. Of course, bigger is better as it reduces any edge diffraction effects. At 2.4GHz, 1 wavelength = 12.5cm so a 6.25 cm long slot would be the minimum. A full wavelength? Half wavelength? Should it be rectangular or would a vertical slot work? See first paragraph. If you want to get fancy, you can cut a 1/2 wave slot in the foil, and turn it into an antenna. It's called a "slot antenna". Watch out for the non-obvious change in polarization. A horizontal slot antenna produces a vertically polarized signal. http://www.antenna-theory.com/antennas/aperture/slot.php Opening the shed door (a full size metal door) temporarily restores a strong signal, but I was hoping a much smaller opening would work equally well. For aesthetic reasons, I can't experiment by cutting various size holes. I suggest you look into what "rickman" suggested. If there's no foil backed insulation in the attic area, and the roof tiles are not RF attenuators or reflectors, moving the radio to the attic should be easy enough. You could also install a fake plastic vent pipe on the roof, and shove the antenna or radio into the pipe. Use your imagination. What's the smallest hole I can cut in the foil coated insulation and be reasonably assured it will work? 6.25 x 6.25cm However, bigger is better and I think twice as large would be more usable. Be sure that the radio is fairly close to the hole. If your unspecified radio has an external antenna connector, find a cheap patch or panel wi-fi antenna on eBay, punch a small hole in the wall, mount the antenna on the outside of the building, and you're done. Something like this: http://www.ebay.com/itm/381490123431 Note that all the gain specifications are lies. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
RF Window Size
Sn!pe wrote:
Have you considered using HomePlug powerline ethernet such as this? $69 for a starter kit seems quite well priced. I assume that you have power in your shed connected to your house wiring. my setup to my own shed over a similar distance works pretty well at ~20 Mbps. http://www.amazon.com/ZyXEL-PLA4205k...all-plug/dp/B0 05GCSZD6 I believe that some amateurs, especially those that use HF, and more especiallly those who listen to non-amateur band transmissions on HF, might find that suggestion bordering on the objectionable. -- Roger Hayter |
RF Window Size
On Fri, 25 Mar 2016 10:58:35 -0400, rickman wrote:
On 3/25/2016 8:50 AM, Roger Hayter wrote: Pat wrote: On Fri, 25 Mar 2016 12:04:11 +0000, (Roger Hayter) wrote: Pat wrote: My antenna theory knowledge is a little weak so I thought you guys might be able to help. Background: I have a shed about 50 feet away from my house that contains water pumps and similar equipment that I monitor. The shed has no windows but was built using normal stud-wall construction. I built a small device that receives information from sensors and then reports back to my PC via my home network. I have no way to run wires to the shed because there is a driveway in between, so I decided to use wi-fi. The shed had a good strong wi-fi signal inside it and everything worked well for the last 5 years. Recently, vinyl siding was added to the shed. The installers used foil coated styrofoam insulation under the siding. The shed has changed from being fairly transparent to RF to being a somewhat leaky faraday shield. The wifi module still works, but just barely. There are lots of missed messages and any interference from devices like the microwave oven in the house shut down communications. Question: I want to create an RF "window" in the shed wall. How big does it need to be to let 2400 MHz signals pass through it? A full wavelength? Half wavelength? Should it be rectangular or would a vertical slot work? Opening the shed door (a full size metal door) temporarily restores a strong signal, but I was hoping a much smaller opening would work equally well. For aesthetic reasons, I can't experiment by cutting various size holes. What's the smallest hole I can cut in the foil coated insulation and be reasonably assured it will work? 4mm, to take the coax to an outside wifi aerial. If you can't find a wifi unit with an aerial socket, change this to usb cable to an outside wifi dongle. but you may then need a 12mm hole for the USB plug. What you have suggested is my "Plan B". The wifi module I am using does not have removable antennas and the sensor box does not have USB capabilities. Thanks for responding. ...Pat I would look into how to couple an external aerial to the built-in aerial of an existing wifif module. ISTR people doing this. Altenative, how about putting a window either in the wall towards the wifi source, or. depending on the roofing material, in the roof which can sometimes be done with acrylic or polycarbonater replacement roofing elements? There's a point. If the metal was added to the walls only, you might be able to rise above that by placing the antenna at the highest point of the roof. I assume that is accessible in a shed. Not this shed. Whoever built it finished the inside with drywall on the walls and ceiling - no access to the attic. (By the way, I expect the signal I am getting now is via the ceiling/roof.) Pat |
RF Window Size
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RF Window Size
On Fri, 25 Mar 2016 16:45:24 +0000, (Roger Hayter)
wrote: Sn!pe wrote: Have you considered using HomePlug powerline ethernet such as this? $69 for a starter kit seems quite well priced. I assume that you have power in your shed connected to your house wiring. my setup to my own shed over a similar distance works pretty well at ~20 Mbps. http://www.amazon.com/ZyXEL-PLA4205k...all-plug/dp/B0 05GCSZD6 I believe that some amateurs, especially those that use HF, and more especiallly those who listen to non-amateur band transmissions on HF, might find that suggestion bordering on the objectionable. Good point. (Although there is already a lot of digital hash in the area throughout HF. Some from my network and some from nearby neighbors). |
RF Window Size
On Fri, 25 Mar 2016 09:37:36 -0700, Jeff Liebermann
wrote: On Fri, 25 Mar 2016 07:48:23 -0400, Pat wrote: I want to create an RF "window" in the shed wall. How big does it need to be to let 2400 MHz signals pass through it? The minimum would be a half wave slot cut through the aluminum foil. The width will vary depending on the type of antenna and its proximity to the slot. Unless you have a half wave dipole near the slot, it won't work. If you're using a patch antenna or something similar, probably a half wave by half wave square hole would be a good minimum. Of course, bigger is better as it reduces any edge diffraction effects. At 2.4GHz, 1 wavelength = 12.5cm so a 6.25 cm long slot would be the minimum. A full wavelength? Half wavelength? Should it be rectangular or would a vertical slot work? See first paragraph. If you want to get fancy, you can cut a 1/2 wave slot in the foil, and turn it into an antenna. It's called a "slot antenna". Watch out for the non-obvious change in polarization. A horizontal slot antenna produces a vertically polarized signal. http://www.antenna-theory.com/antennas/aperture/slot.php Opening the shed door (a full size metal door) temporarily restores a strong signal, but I was hoping a much smaller opening would work equally well. For aesthetic reasons, I can't experiment by cutting various size holes. I suggest you look into what "rickman" suggested. If there's no foil backed insulation in the attic area, and the roof tiles are not RF attenuators or reflectors, moving the radio to the attic should be easy enough. You could also install a fake plastic vent pipe on the roof, and shove the antenna or radio into the pipe. Use your imagination. What's the smallest hole I can cut in the foil coated insulation and be reasonably assured it will work? 6.25 x 6.25cm However, bigger is better and I think twice as large would be more usable. Be sure that the radio is fairly close to the hole. If your unspecified radio has an external antenna connector, find a cheap patch or panel wi-fi antenna on eBay, punch a small hole in the wall, mount the antenna on the outside of the building, and you're done. Something like this: http://www.ebay.com/itm/381490123431 Note that all the gain specifications are lies. Thank you Jeff. That is what I was looking for. Thanks to all the others who responded as well. I went over to my local Home Depot and found a plastic cover plate that can cover a 14x14 inch (35x35 cm) hole in drywall. I plan to remove a piece of drywall that size and then remove a piece of the foil covered insulation - from the inside. That will give me a good size RF window without changing the outside appearance of the shed at all. I will then install the plastic cover on the inside and place the wifi module near its center. I will let you all know how it all works out in a few days. Thanks again for your help. 73, Pat |
RF Window Size
Pat wrote:
On Fri, 25 Mar 2016 10:58:35 -0400, rickman wrote: On 3/25/2016 8:50 AM, Roger Hayter wrote: Pat wrote: On Fri, 25 Mar 2016 12:04:11 +0000, (Roger Hayter) wrote: Pat wrote: My antenna theory knowledge is a little weak so I thought you guys might be able to help. Background: I have a shed about 50 feet away from my house that contains water pumps and similar equipment that I monitor. The shed has no windows but was built using normal stud-wall construction. I built a small device that receives information from sensors and then reports back to my PC via my home network. I have no way to run wires to the shed because there is a driveway in between, so I decided to use wi-fi. The shed had a good strong wi-fi signal inside it and everything worked well for the last 5 years. Recently, vinyl siding was added to the shed. The installers used foil coated styrofoam insulation under the siding. The shed has changed from being fairly transparent to RF to being a somewhat leaky faraday shield. The wifi module still works, but just barely. There are lots of missed messages and any interference from devices like the microwave oven in the house shut down communications. Question: I want to create an RF "window" in the shed wall. How big does it need to be to let 2400 MHz signals pass through it? A full wavelength? Half wavelength? Should it be rectangular or would a vertical slot work? Opening the shed door (a full size metal door) temporarily restores a strong signal, but I was hoping a much smaller opening would work equally well. For aesthetic reasons, I can't experiment by cutting various size holes. What's the smallest hole I can cut in the foil coated insulation and be reasonably assured it will work? 4mm, to take the coax to an outside wifi aerial. If you can't find a wifi unit with an aerial socket, change this to usb cable to an outside wifi dongle. but you may then need a 12mm hole for the USB plug. What you have suggested is my "Plan B". The wifi module I am using does not have removable antennas and the sensor box does not have USB capabilities. Thanks for responding. ...Pat I would look into how to couple an external aerial to the built-in aerial of an existing wifif module. ISTR people doing this. Altenative, how about putting a window either in the wall towards the wifi source, or. depending on the roofing material, in the roof which can sometimes be done with acrylic or polycarbonater replacement roofing elements? There's a point. If the metal was added to the walls only, you might be able to rise above that by placing the antenna at the highest point of the roof. I assume that is accessible in a shed. Not this shed. Whoever built it finished the inside with drywall on the walls and ceiling - no access to the attic. (By the way, I expect the signal I am getting now is via the ceiling/roof.) Pat Drywall is very easy to cut and patch up. Cut an access hole in the ceiling and put the RF stuff on top of the drywall. Put a trap door over the access hole if you want to keep it all neat. -- Jim Pennino |
RF Window Size
On 3/25/2016 2:10 PM, Pat wrote:
On Fri, 25 Mar 2016 10:58:35 -0400, rickman wrote: On 3/25/2016 8:50 AM, Roger Hayter wrote: Pat wrote: On Fri, 25 Mar 2016 12:04:11 +0000, (Roger Hayter) wrote: Pat wrote: My antenna theory knowledge is a little weak so I thought you guys might be able to help. Background: I have a shed about 50 feet away from my house that contains water pumps and similar equipment that I monitor. The shed has no windows but was built using normal stud-wall construction. I built a small device that receives information from sensors and then reports back to my PC via my home network. I have no way to run wires to the shed because there is a driveway in between, so I decided to use wi-fi. The shed had a good strong wi-fi signal inside it and everything worked well for the last 5 years. Recently, vinyl siding was added to the shed. The installers used foil coated styrofoam insulation under the siding. The shed has changed from being fairly transparent to RF to being a somewhat leaky faraday shield. The wifi module still works, but just barely. There are lots of missed messages and any interference from devices like the microwave oven in the house shut down communications. Question: I want to create an RF "window" in the shed wall. How big does it need to be to let 2400 MHz signals pass through it? A full wavelength? Half wavelength? Should it be rectangular or would a vertical slot work? Opening the shed door (a full size metal door) temporarily restores a strong signal, but I was hoping a much smaller opening would work equally well. For aesthetic reasons, I can't experiment by cutting various size holes. What's the smallest hole I can cut in the foil coated insulation and be reasonably assured it will work? 4mm, to take the coax to an outside wifi aerial. If you can't find a wifi unit with an aerial socket, change this to usb cable to an outside wifi dongle. but you may then need a 12mm hole for the USB plug. What you have suggested is my "Plan B". The wifi module I am using does not have removable antennas and the sensor box does not have USB capabilities. Thanks for responding. ...Pat I would look into how to couple an external aerial to the built-in aerial of an existing wifif module. ISTR people doing this. Altenative, how about putting a window either in the wall towards the wifi source, or. depending on the roofing material, in the roof which can sometimes be done with acrylic or polycarbonater replacement roofing elements? There's a point. If the metal was added to the walls only, you might be able to rise above that by placing the antenna at the highest point of the roof. I assume that is accessible in a shed. Not this shed. Whoever built it finished the inside with drywall on the walls and ceiling - no access to the attic. (By the way, I expect the signal I am getting now is via the ceiling/roof.) I wanted to modify the lighting on my porch. The ceiling is covered with wood. So I cut a panel and framed it with some nice wood to make an access hatch. You can do the same thing with the drywall. -- Rick |
RF Window Size
On 3/25/2016 12:45 PM, Roger Hayter wrote:
Sn!pe wrote: Have you considered using HomePlug powerline ethernet such as this? $69 for a starter kit seems quite well priced. I assume that you have power in your shed connected to your house wiring. my setup to my own shed over a similar distance works pretty well at ~20 Mbps. http://www.amazon.com/ZyXEL-PLA4205k...all-plug/dp/B0 05GCSZD6 I believe that some amateurs, especially those that use HF, and more especiallly those who listen to non-amateur band transmissions on HF, might find that suggestion bordering on the objectionable. Is the HomePlug setup a known offender? They might use something like CDMA to spread the noise over the band greatly reducing any interference. -- Rick |
RF Window Size
On 3/25/2016 2:25 PM, Pat wrote:
On Fri, 25 Mar 2016 09:37:36 -0700, Jeff Liebermann wrote: On Fri, 25 Mar 2016 07:48:23 -0400, Pat wrote: I want to create an RF "window" in the shed wall. How big does it need to be to let 2400 MHz signals pass through it? The minimum would be a half wave slot cut through the aluminum foil. The width will vary depending on the type of antenna and its proximity to the slot. Unless you have a half wave dipole near the slot, it won't work. If you're using a patch antenna or something similar, probably a half wave by half wave square hole would be a good minimum. Of course, bigger is better as it reduces any edge diffraction effects. At 2.4GHz, 1 wavelength = 12.5cm so a 6.25 cm long slot would be the minimum. A full wavelength? Half wavelength? Should it be rectangular or would a vertical slot work? See first paragraph. If you want to get fancy, you can cut a 1/2 wave slot in the foil, and turn it into an antenna. It's called a "slot antenna". Watch out for the non-obvious change in polarization. A horizontal slot antenna produces a vertically polarized signal. http://www.antenna-theory.com/antennas/aperture/slot.php Opening the shed door (a full size metal door) temporarily restores a strong signal, but I was hoping a much smaller opening would work equally well. For aesthetic reasons, I can't experiment by cutting various size holes. I suggest you look into what "rickman" suggested. If there's no foil backed insulation in the attic area, and the roof tiles are not RF attenuators or reflectors, moving the radio to the attic should be easy enough. You could also install a fake plastic vent pipe on the roof, and shove the antenna or radio into the pipe. Use your imagination. What's the smallest hole I can cut in the foil coated insulation and be reasonably assured it will work? 6.25 x 6.25cm However, bigger is better and I think twice as large would be more usable. Be sure that the radio is fairly close to the hole. If your unspecified radio has an external antenna connector, find a cheap patch or panel wi-fi antenna on eBay, punch a small hole in the wall, mount the antenna on the outside of the building, and you're done. Something like this: http://www.ebay.com/itm/381490123431 Note that all the gain specifications are lies. Thank you Jeff. That is what I was looking for. Thanks to all the others who responded as well. I went over to my local Home Depot and found a plastic cover plate that can cover a 14x14 inch (35x35 cm) hole in drywall. I plan to remove a piece of drywall that size and then remove a piece of the foil covered insulation - from the inside. That will give me a good size RF window without changing the outside appearance of the shed at all. I will then install the plastic cover on the inside and place the wifi module near its center. I will let you all know how it all works out in a few days. Before hacking out insulation, I'd try the attic approach first. -- Rick |
RF Window Size
rickman wrote:
On 3/25/2016 12:45 PM, Roger Hayter wrote: Sn!pe wrote: Have you considered using HomePlug powerline ethernet such as this? $69 for a starter kit seems quite well priced. I assume that you have power in your shed connected to your house wiring. my setup to my own shed over a similar distance works pretty well at ~20 Mbps. http://www.amazon.com/ZyXEL-PLA4205k...all-plug/dp/B0 05GCSZD6 I believe that some amateurs, especially those that use HF, and more especiallly those who listen to non-amateur band transmissions on HF, might find that suggestion bordering on the objectionable. Is the HomePlug setup a known offender? They might use something like CDMA to spread the noise over the band greatly reducing any interference. I believe they already use most of the HF band (apart from notches around the amateur bands) for bandwidth reason. The British national society seriously considered sueing the regulator for allowing them to vandalise the spectrum against the previously estabisihed interference rulels. -- Roger Hayter |
RF Window Size
On Fri, 25 Mar 2016 14:57:29 -0400, rickman wrote:
On 3/25/2016 2:25 PM, Pat wrote: On Fri, 25 Mar 2016 09:37:36 -0700, Jeff Liebermann wrote: On Fri, 25 Mar 2016 07:48:23 -0400, Pat wrote: I want to create an RF "window" in the shed wall. How big does it need to be to let 2400 MHz signals pass through it? The minimum would be a half wave slot cut through the aluminum foil. The width will vary depending on the type of antenna and its proximity to the slot. Unless you have a half wave dipole near the slot, it won't work. If you're using a patch antenna or something similar, probably a half wave by half wave square hole would be a good minimum. Of course, bigger is better as it reduces any edge diffraction effects. At 2.4GHz, 1 wavelength = 12.5cm so a 6.25 cm long slot would be the minimum. A full wavelength? Half wavelength? Should it be rectangular or would a vertical slot work? See first paragraph. If you want to get fancy, you can cut a 1/2 wave slot in the foil, and turn it into an antenna. It's called a "slot antenna". Watch out for the non-obvious change in polarization. A horizontal slot antenna produces a vertically polarized signal. http://www.antenna-theory.com/antennas/aperture/slot.php Opening the shed door (a full size metal door) temporarily restores a strong signal, but I was hoping a much smaller opening would work equally well. For aesthetic reasons, I can't experiment by cutting various size holes. I suggest you look into what "rickman" suggested. If there's no foil backed insulation in the attic area, and the roof tiles are not RF attenuators or reflectors, moving the radio to the attic should be easy enough. You could also install a fake plastic vent pipe on the roof, and shove the antenna or radio into the pipe. Use your imagination. What's the smallest hole I can cut in the foil coated insulation and be reasonably assured it will work? 6.25 x 6.25cm However, bigger is better and I think twice as large would be more usable. Be sure that the radio is fairly close to the hole. If your unspecified radio has an external antenna connector, find a cheap patch or panel wi-fi antenna on eBay, punch a small hole in the wall, mount the antenna on the outside of the building, and you're done. Something like this: http://www.ebay.com/itm/381490123431 Note that all the gain specifications are lies. Thank you Jeff. That is what I was looking for. Thanks to all the others who responded as well. I went over to my local Home Depot and found a plastic cover plate that can cover a 14x14 inch (35x35 cm) hole in drywall. I plan to remove a piece of drywall that size and then remove a piece of the foil covered insulation - from the inside. That will give me a good size RF window without changing the outside appearance of the shed at all. I will then install the plastic cover on the inside and place the wifi module near its center. I will let you all know how it all works out in a few days. Before hacking out insulation, I'd try the attic approach first. Too late. I already did it and without moving the wifi module to be near the hole, the signal already improved from marginal (a red indicator LED) to OK (the LED is now yellow). Tomorrow, I will move the wifi module to be near the hole. I expect a green LED after that. Pat |
RF Window Size
On Fri, 25 Mar 2016 18:32:37 -0000, wrote:
Pat wrote: On Fri, 25 Mar 2016 10:58:35 -0400, rickman wrote: On 3/25/2016 8:50 AM, Roger Hayter wrote: Pat wrote: On Fri, 25 Mar 2016 12:04:11 +0000, (Roger Hayter) wrote: Pat wrote: My antenna theory knowledge is a little weak so I thought you guys might be able to help. Background: I have a shed about 50 feet away from my house that contains water pumps and similar equipment that I monitor. The shed has no windows but was built using normal stud-wall construction. I built a small device that receives information from sensors and then reports back to my PC via my home network. I have no way to run wires to the shed because there is a driveway in between, so I decided to use wi-fi. The shed had a good strong wi-fi signal inside it and everything worked well for the last 5 years. Recently, vinyl siding was added to the shed. The installers used foil coated styrofoam insulation under the siding. The shed has changed from being fairly transparent to RF to being a somewhat leaky faraday shield. The wifi module still works, but just barely. There are lots of missed messages and any interference from devices like the microwave oven in the house shut down communications. Question: I want to create an RF "window" in the shed wall. How big does it need to be to let 2400 MHz signals pass through it? A full wavelength? Half wavelength? Should it be rectangular or would a vertical slot work? Opening the shed door (a full size metal door) temporarily restores a strong signal, but I was hoping a much smaller opening would work equally well. For aesthetic reasons, I can't experiment by cutting various size holes. What's the smallest hole I can cut in the foil coated insulation and be reasonably assured it will work? 4mm, to take the coax to an outside wifi aerial. If you can't find a wifi unit with an aerial socket, change this to usb cable to an outside wifi dongle. but you may then need a 12mm hole for the USB plug. What you have suggested is my "Plan B". The wifi module I am using does not have removable antennas and the sensor box does not have USB capabilities. Thanks for responding. ...Pat I would look into how to couple an external aerial to the built-in aerial of an existing wifif module. ISTR people doing this. Altenative, how about putting a window either in the wall towards the wifi source, or. depending on the roofing material, in the roof which can sometimes be done with acrylic or polycarbonater replacement roofing elements? There's a point. If the metal was added to the walls only, you might be able to rise above that by placing the antenna at the highest point of the roof. I assume that is accessible in a shed. Not this shed. Whoever built it finished the inside with drywall on the walls and ceiling - no access to the attic. (By the way, I expect the signal I am getting now is via the ceiling/roof.) Pat Drywall is very easy to cut and patch up. Cut an access hole in the ceiling and put the RF stuff on top of the drywall. Put a trap door over the access hole if you want to keep it all neat. The problem with that is the shed has a gable roof. The new siding and foil backed insulation goes all the way to the peak on the ends. Unfortunately, the wifi signal comes from one of those ends. Pat |
RF Window Size
On Fri, 25 Mar 2016 14:54:16 -0400, rickman wrote:
On 3/25/2016 2:10 PM, Pat wrote: On Fri, 25 Mar 2016 10:58:35 -0400, rickman wrote: On 3/25/2016 8:50 AM, Roger Hayter wrote: Pat wrote: On Fri, 25 Mar 2016 12:04:11 +0000, (Roger Hayter) wrote: Pat wrote: My antenna theory knowledge is a little weak so I thought you guys might be able to help. Background: I have a shed about 50 feet away from my house that contains water pumps and similar equipment that I monitor. The shed has no windows but was built using normal stud-wall construction. I built a small device that receives information from sensors and then reports back to my PC via my home network. I have no way to run wires to the shed because there is a driveway in between, so I decided to use wi-fi. The shed had a good strong wi-fi signal inside it and everything worked well for the last 5 years. Recently, vinyl siding was added to the shed. The installers used foil coated styrofoam insulation under the siding. The shed has changed from being fairly transparent to RF to being a somewhat leaky faraday shield. The wifi module still works, but just barely. There are lots of missed messages and any interference from devices like the microwave oven in the house shut down communications. Question: I want to create an RF "window" in the shed wall. How big does it need to be to let 2400 MHz signals pass through it? A full wavelength? Half wavelength? Should it be rectangular or would a vertical slot work? Opening the shed door (a full size metal door) temporarily restores a strong signal, but I was hoping a much smaller opening would work equally well. For aesthetic reasons, I can't experiment by cutting various size holes. What's the smallest hole I can cut in the foil coated insulation and be reasonably assured it will work? 4mm, to take the coax to an outside wifi aerial. If you can't find a wifi unit with an aerial socket, change this to usb cable to an outside wifi dongle. but you may then need a 12mm hole for the USB plug. What you have suggested is my "Plan B". The wifi module I am using does not have removable antennas and the sensor box does not have USB capabilities. Thanks for responding. ...Pat I would look into how to couple an external aerial to the built-in aerial of an existing wifif module. ISTR people doing this. Altenative, how about putting a window either in the wall towards the wifi source, or. depending on the roofing material, in the roof which can sometimes be done with acrylic or polycarbonater replacement roofing elements? There's a point. If the metal was added to the walls only, you might be able to rise above that by placing the antenna at the highest point of the roof. I assume that is accessible in a shed. Not this shed. Whoever built it finished the inside with drywall on the walls and ceiling - no access to the attic. (By the way, I expect the signal I am getting now is via the ceiling/roof.) I wanted to modify the lighting on my porch. The ceiling is covered with wood. So I cut a panel and framed it with some nice wood to make an access hatch. You can do the same thing with the drywall. I ended up using a plastic cover plate I found at Home Depot. It is essential what you are recommending, but instead of making it from wood, it comes ready made. It only cost $14 USD. It has a frame that spans to studs and a 14" x 14" removalble door insert. Not as nice as what you propose, but for the shed, it is one of the nicest looking things in there :-) |
RF Window Size
On 3/25/2016 5:06 PM, Pat wrote:
On Fri, 25 Mar 2016 14:54:16 -0400, rickman wrote: On 3/25/2016 2:10 PM, Pat wrote: On Fri, 25 Mar 2016 10:58:35 -0400, rickman wrote: On 3/25/2016 8:50 AM, Roger Hayter wrote: Pat wrote: On Fri, 25 Mar 2016 12:04:11 +0000, (Roger Hayter) wrote: Pat wrote: My antenna theory knowledge is a little weak so I thought you guys might be able to help. Background: I have a shed about 50 feet away from my house that contains water pumps and similar equipment that I monitor. The shed has no windows but was built using normal stud-wall construction. I built a small device that receives information from sensors and then reports back to my PC via my home network. I have no way to run wires to the shed because there is a driveway in between, so I decided to use wi-fi. The shed had a good strong wi-fi signal inside it and everything worked well for the last 5 years. Recently, vinyl siding was added to the shed. The installers used foil coated styrofoam insulation under the siding. The shed has changed from being fairly transparent to RF to being a somewhat leaky faraday shield. The wifi module still works, but just barely. There are lots of missed messages and any interference from devices like the microwave oven in the house shut down communications. Question: I want to create an RF "window" in the shed wall. How big does it need to be to let 2400 MHz signals pass through it? A full wavelength? Half wavelength? Should it be rectangular or would a vertical slot work? Opening the shed door (a full size metal door) temporarily restores a strong signal, but I was hoping a much smaller opening would work equally well. For aesthetic reasons, I can't experiment by cutting various size holes. What's the smallest hole I can cut in the foil coated insulation and be reasonably assured it will work? 4mm, to take the coax to an outside wifi aerial. If you can't find a wifi unit with an aerial socket, change this to usb cable to an outside wifi dongle. but you may then need a 12mm hole for the USB plug. What you have suggested is my "Plan B". The wifi module I am using does not have removable antennas and the sensor box does not have USB capabilities. Thanks for responding. ...Pat I would look into how to couple an external aerial to the built-in aerial of an existing wifif module. ISTR people doing this. Altenative, how about putting a window either in the wall towards the wifi source, or. depending on the roofing material, in the roof which can sometimes be done with acrylic or polycarbonater replacement roofing elements? There's a point. If the metal was added to the walls only, you might be able to rise above that by placing the antenna at the highest point of the roof. I assume that is accessible in a shed. Not this shed. Whoever built it finished the inside with drywall on the walls and ceiling - no access to the attic. (By the way, I expect the signal I am getting now is via the ceiling/roof.) I wanted to modify the lighting on my porch. The ceiling is covered with wood. So I cut a panel and framed it with some nice wood to make an access hatch. You can do the same thing with the drywall. I ended up using a plastic cover plate I found at Home Depot. It is essential what you are recommending, but instead of making it from wood, it comes ready made. It only cost $14 USD. It has a frame that spans to studs and a 14" x 14" removalble door insert. Not as nice as what you propose, but for the shed, it is one of the nicest looking things in there :-) Mine was basically free. The wood was reused as the removable panel and the trim wood was scrap. I think I nail the trim to the door and used a couple of screws to hold it to the ceiling. Still $14 is not much more than free and saves some work. -- Rick |
RF Window Size
On 3/25/2016 5:33 PM, Sn!pe wrote:
Pat wrote: On Fri, 25 Mar 2016 15:13:09 +0000, (Sn!pe) wrote: [...] Have you considered using HomePlug powerline ethernet such as this? $69 for a starter kit seems quite well priced. I assume that you have power in your shed connected to your house wiring. my setup to my own shed over a similar distance works pretty well at ~20 Mbps. http://www.amazon.com/ZyXEL-PLA4205kit-HomePlug-Powerline-Wall-plug/dp/B005GCSZD6 Yes. I have considered that. However, the shed is powered from a separate feed back the power company. I didn't want to risk the money to buy one of these only to find its signal didn't make it through the power company's transformer. Pat Agreed, I think it's highly unlikely that the signal would get through a transformer. I've heard that it can even have trouble getting from one segment of house wiring to another if they're on different sections of the consumer unit distribution board, although I haven't found that to be a problem here. No, a signal like this definitely won't get through the transformer. The power companies in some areas use the electric wires to send control signals like a network. They have to install high frequency jumpers to get past transformers. -- Rick |
RF Window Size
On Fri, 25 Mar 2016 16:54:42 -0400, Pat wrote:
Before hacking out insulation, I'd try the attic approach first. Too late. I already did it and without moving the wifi module to be near the hole, the signal already improved from marginal (a red indicator LED) to OK (the LED is now yellow). Tomorrow, I will move the wifi module to be near the hole. I expect a green LED after that. Pat Final update: I moved the wifi device to right in front of my RF hole. The LED is green and everything is back to normal. I replaced the old insulation with non-foil type and covered the hole with the $15 cover plate a mentioned in previous posts. All is well. Thanks. Pat |
RF Window Size
On 3/26/2016 1:45 PM, Pat wrote:
On Fri, 25 Mar 2016 16:54:42 -0400, Pat wrote: Before hacking out insulation, I'd try the attic approach first. Too late. I already did it and without moving the wifi module to be near the hole, the signal already improved from marginal (a red indicator LED) to OK (the LED is now yellow). Tomorrow, I will move the wifi module to be near the hole. I expect a green LED after that. Pat Final update: I moved the wifi device to right in front of my RF hole. The LED is green and everything is back to normal. I replaced the old insulation with non-foil type and covered the hole with the $15 cover plate a mentioned in previous posts. All is well. Thanks. Good job. I will say the metal is on the insulation for a reason. It may be moisture barrier. Is that important with your shed? -- Rick |
RF Window Size
On Sat, 26 Mar 2016 14:09:26 -0400, rickman wrote:
On 3/26/2016 1:45 PM, Pat wrote: On Fri, 25 Mar 2016 16:54:42 -0400, Pat wrote: Before hacking out insulation, I'd try the attic approach first. Too late. I already did it and without moving the wifi module to be near the hole, the signal already improved from marginal (a red indicator LED) to OK (the LED is now yellow). Tomorrow, I will move the wifi module to be near the hole. I expect a green LED after that. Pat Final update: I moved the wifi device to right in front of my RF hole. The LED is green and everything is back to normal. I replaced the old insulation with non-foil type and covered the hole with the $15 cover plate a mentioned in previous posts. All is well. Thanks. Good job. I will say the metal is on the insulation for a reason. It may be moisture barrier. Is that important with your shed? It can't be very important since none of it was there until the new siding was added. The siding was added for aesthetic reasons - not to solve any other problems. However, I did add a plastic sheet over the hole before replacing the fiberglass batt insulation in the stud wall. I will keep an eye on it in extreme weather (hot or cold) to make sure. Pat |
RF Window Size
On 3/26/2016 4:49 PM, Pat wrote:
On Sat, 26 Mar 2016 14:09:26 -0400, rickman wrote: On 3/26/2016 1:45 PM, Pat wrote: On Fri, 25 Mar 2016 16:54:42 -0400, Pat wrote: Before hacking out insulation, I'd try the attic approach first. Too late. I already did it and without moving the wifi module to be near the hole, the signal already improved from marginal (a red indicator LED) to OK (the LED is now yellow). Tomorrow, I will move the wifi module to be near the hole. I expect a green LED after that. Pat Final update: I moved the wifi device to right in front of my RF hole. The LED is green and everything is back to normal. I replaced the old insulation with non-foil type and covered the hole with the $15 cover plate a mentioned in previous posts. All is well. Thanks. Good job. I will say the metal is on the insulation for a reason. It may be moisture barrier. Is that important with your shed? It can't be very important since none of it was there until the new siding was added. The siding was added for aesthetic reasons - not to solve any other problems. However, I did add a plastic sheet over the hole before replacing the fiberglass batt insulation in the stud wall. I will keep an eye on it in extreme weather (hot or cold) to make sure. Just curious, which side is the metal and plastic on, inside or out? I expect they used materials intended for living space just because that is what they normally use. None of this is likely to be important for your use. I think the vapor barrier is normally on the inside to prevent moisture from inside getting into the insulation which would then conduct heat more readily. In any event I think you have a winner. -- Rick |
RF Window Size
On Sat, 26 Mar 2016 18:30:50 -0400, rickman wrote:
Just curious, which side is the metal and plastic on, inside or out? I expect they used materials intended for living space just because that is what they normally use. None of this is likely to be important for your use. I think the vapor barrier is normally on the inside to prevent moisture from inside getting into the insulation which would then conduct heat more readily. In any event I think you have a winner. Before cutting the hole, I would have said outside, but it turns out the foil was on both. And, yes, you are correct that they used the same material they brought for the big job - siding the occupied building. Pat |
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