Hi George,
I know this isn't tube related , but I bet it would sell well and keep tubelab going along nicely through any down turns .
I would be interested in a 70 db+ amp as I newly realized one can put a put a proper antenna in a building to use nicely with cell phones.
Thanks very much for your great knowledge you have passed on over the years.
Randy
I know this isn't tube related , but I bet it would sell well and keep tubelab going along nicely through any down turns .
I would be interested in a 70 db+ amp as I newly realized one can put a put a proper antenna in a building to use nicely with cell phones.
Thanks very much for your great knowledge you have passed on over the years.
Randy
I get asked about these a couple of times a year, as many people know that I was an RF design engineer at Motorola for many years including about 5 years in a phone design group.
I live in a rural area about 2 miles from a small town. We are down in a valley between ridges so that we get very poor cell coverage, few radio stations and no TV signals. About 5 years ago I set out to design a booster, but quickly discovered how complicated it would be. While researching the needed circuitry I spotted someone on Ebay selling "repair boards" for a $500 Wilson cell booster for Under $100. I simply bought one of those boards, made a simple power supply for it, and hooked it up. I could not buy the necessary parts to make it for $100.
The picture shows the board I got. It contains about 20 amplifier chips, 18 SAW filters, 4 BAW duplexers, and a microcontroller to control the gain of each stage.
This is a 4 band booster made before 5G was a reality. Today some places in the US have 8 working bands for the two major carriers, and 5 for number 3.
Here in rural nowhere, 3 bands are required to just for the phone to operate. Voice calls go on band 2 or 4 depending on signal quality and cell site loading, texts can be on band 2 or 4 and bulk data needs band 13 or 14 depending on AT&T or Verizon. There must be a separate path for inbound or outbound communication, as both are happening simultaneously on slightly different frequencies. A whole lot of RF band pass filters are needed to keep it all separated.
Technically building these things are illegal in the US, and probably in Canada as well. All must have FCC / DOC certification, and approval of the cell carrier that they would be used on. Here the use and installation of one of these devices must be approved by the cell carrier on an individual basis too. So even my device is against the rules, and they vanished from Ebay rather quickly. This rules out making them a Tubelab product.
The last discussion I had was here:
make a cell phone antenna booster repeater
I live in a rural area about 2 miles from a small town. We are down in a valley between ridges so that we get very poor cell coverage, few radio stations and no TV signals. About 5 years ago I set out to design a booster, but quickly discovered how complicated it would be. While researching the needed circuitry I spotted someone on Ebay selling "repair boards" for a $500 Wilson cell booster for Under $100. I simply bought one of those boards, made a simple power supply for it, and hooked it up. I could not buy the necessary parts to make it for $100.
The picture shows the board I got. It contains about 20 amplifier chips, 18 SAW filters, 4 BAW duplexers, and a microcontroller to control the gain of each stage.
This is a 4 band booster made before 5G was a reality. Today some places in the US have 8 working bands for the two major carriers, and 5 for number 3.
Here in rural nowhere, 3 bands are required to just for the phone to operate. Voice calls go on band 2 or 4 depending on signal quality and cell site loading, texts can be on band 2 or 4 and bulk data needs band 13 or 14 depending on AT&T or Verizon. There must be a separate path for inbound or outbound communication, as both are happening simultaneously on slightly different frequencies. A whole lot of RF band pass filters are needed to keep it all separated.
Technically building these things are illegal in the US, and probably in Canada as well. All must have FCC / DOC certification, and approval of the cell carrier that they would be used on. Here the use and installation of one of these devices must be approved by the cell carrier on an individual basis too. So even my device is against the rules, and they vanished from Ebay rather quickly. This rules out making them a Tubelab product.
The last discussion I had was here:
make a cell phone antenna booster repeater
Attachments
George,
That was a thoughtful and very useful discussion of the issues involved. Thank you, HeyBill
That was a thoughtful and very useful discussion of the issues involved. Thank you, HeyBill