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Cost of the Cheapest LoFi AM Transmitter ~ 20 - 30m Range

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Bret Cahill
Guest

Sun Dec 22, 2019 7:49 pm   



Everything on Ebay seems to be more than $3.

Jasen Betts
Guest

Sun Dec 22, 2019 11:41 pm   



On 2019-12-22, Bret Cahill <bretcahill_at_aol.com> wrote:
> Everything on Ebay seems to be more than $3.

because they are resellers.

--
Jasen.

default
Guest

Sun Dec 22, 2019 11:43 pm   



On Sun, 22 Dec 2019 09:49:34 -0800 (PST), Bret Cahill
<bretcahill_at_aol.com> wrote:

>Everything on Ebay seems to be more than $3.

AM broadcast band? Chances are if you had to buy all new parts and
build it yourself you'd spend more than $3.

I built those in the 50's. The 3.5 mhy choke I used might be more
than 3 bucks today, and back then transistors were more expensive.


http://www.learningelectronics.net/circuits/simple-am-transmitter.html

http://www.bowdenshobbycircuits.info/page6.htm#amtrans.gif

http://www.zen22142.zen.co.uk/Circuits/rf/amtx.htm

http://www.circuitstoday.com/am-transmitter-circuit

Bret Cahill
Guest

Mon Dec 23, 2019 6:59 pm   



Quote:
Everything on Ebay seems to be more than $3.

AM broadcast band? Chances are if you had to buy all new parts and
build it yourself you'd spend more than $3.

I built those in the 50's. The 3.5 mhy choke I used might be more
than 3 bucks today, and back then transistors were more expensive.


http://www.learningelectronics.net/circuits/simple-am-transmitter.html

http://www.bowdenshobbycircuits.info/page6.htm#amtrans.gif

http://www.zen22142.zen.co.uk/Circuits/rf/amtx.htm

http://www.circuitstoday.com/am-transmitter-circuit


Thanks.

A mic isn't necessary -- just a tone to warn motorists that a cyclist is around the curve.


Guest

Tue Dec 24, 2019 12:35 am   



On Monday, 23 December 2019 17:00:03 UTC, Bret Cahill wrote:
Quote:
Everything on Ebay seems to be more than $3.

AM broadcast band? Chances are if you had to buy all new parts and
build it yourself you'd spend more than $3.

I built those in the 50's. The 3.5 mhy choke I used might be more
than 3 bucks today, and back then transistors were more expensive.


http://www.learningelectronics.net/circuits/simple-am-transmitter.html

http://www.bowdenshobbycircuits.info/page6.htm#amtrans.gif

http://www.zen22142.zen.co.uk/Circuits/rf/amtx.htm

http://www.circuitstoday.com/am-transmitter-circuit

Thanks.

A mic isn't necessary -- just a tone to warn motorists that a cyclist is around the curve.


Components are nearly free these days. I doubt it'd cost me a cent to hairball a small transmitter. Those with no stock or knowledge would need to pay retail though.

Bret Cahill
Guest

Wed Dec 25, 2019 4:26 am   



Quote:
Everything on Ebay seems to be more than $3.

AM broadcast band? Chances are if you had to buy all new parts and
build it yourself you'd spend more than $3.

I built those in the 50's. The 3.5 mhy choke I used might be more
than 3 bucks today, and back then transistors were more expensive.


http://www.learningelectronics.net/circuits/simple-am-transmitter.html

http://www.bowdenshobbycircuits.info/page6.htm#amtrans.gif

http://www.zen22142.zen.co.uk/Circuits/rf/amtx.htm

http://www.circuitstoday.com/am-transmitter-circuit

Thanks.

A mic isn't necessary -- just a tone to warn motorists that a cyclist is around the curve.

Components are nearly free these days. I doubt it'd cost me a cent to hairball a small transmitter. Those with no stock or knowledge would need to pay retail though.


You might consider Shark Tank. There are no patents on this AFAIK.

I'm too lazy for it. I'm extraordinarily lazy. I'm so lazy I'm gonna develop a low [near zero] maintenance bicycle even if it works me to death.

An epic battle is raging within: The irreversible force lazy vs the immovable object lazy.

So, being lazy, other than batteries, any time I do anything that involves electronics I assume 0 cost and, if power is involved, 100% efficiency.

Batteries gonna make me drink a cup of coffee, start a spread sheet, ruin my _entire_ morning . . .

Jasen Betts
Guest

Wed Dec 25, 2019 4:57 am   



On 2019-12-23, Bret Cahill <bretcahill_at_aol.com> wrote:
Quote:
Everything on Ebay seems to be more than $3.

AM broadcast band? Chances are if you had to buy all new parts and
build it yourself you'd spend more than $3.

I built those in the 50's. The 3.5 mhy choke I used might be more
than 3 bucks today, and back then transistors were more expensive.


http://www.learningelectronics.net/circuits/simple-am-transmitter.html

http://www.bowdenshobbycircuits.info/page6.htm#amtrans.gif

http://www.zen22142.zen.co.uk/Circuits/rf/amtx.htm

http://www.circuitstoday.com/am-transmitter-circuit

Thanks.

A mic isn't necessary -- just a tone to warn motorists that a cyclist is around the curve.


So why use AM, why not BLE?

--
Jasen.

default
Guest

Wed Dec 25, 2019 4:53 pm   



On Mon, 23 Dec 2019 08:59:58 -0800 (PST), Bret Cahill
<bretcahill_at_aol.com> wrote:

Quote:
Everything on Ebay seems to be more than $3.

AM broadcast band? Chances are if you had to buy all new parts and
build it yourself you'd spend more than $3.

I built those in the 50's. The 3.5 mhy choke I used might be more
than 3 bucks today, and back then transistors were more expensive.


http://www.learningelectronics.net/circuits/simple-am-transmitter.html

http://www.bowdenshobbycircuits.info/page6.htm#amtrans.gif

http://www.zen22142.zen.co.uk/Circuits/rf/amtx.htm

http://www.circuitstoday.com/am-transmitter-circuit

Thanks.

A mic isn't necessary -- just a tone to warn motorists that a cyclist is around the curve.

Radio amateurs, back in the heyday of home-brew, would make little AM
transmitters operating from batteries so they could have "hidden
transmitter hunts," with home-brew radio direction finding rigs.

The government still does the same things - on an industrial scale. I
suspect they are using angle of arrival and time of flight to achieve
the same thing fancy antennas alone used to do. (that's based on
their abandoning the large circular antenna arrays that used to do the
same thing, called a Wullenweber array)

https://www.google.com/search?lr=&as_qdr=all&q=wullenweber&tbm=isch&source=univ&sa=X&ved=2ahUKEwjuuN_khdHmAhWvct8KHecmDyQQsAR6BAgHEAE&biw=1024&bih=646

https://tinyurl.com/tg46nua

Jasen Betts
Guest

Wed Dec 25, 2019 9:43 pm   



On 2019-12-25, default <default_at_defaulter.neo> wrote:
Quote:
On Mon, 23 Dec 2019 08:59:58 -0800 (PST), Bret Cahill
bretcahill_at_aol.com> wrote:

Everything on Ebay seems to be more than $3.

AM broadcast band? Chances are if you had to buy all new parts and
build it yourself you'd spend more than $3.

I built those in the 50's. The 3.5 mhy choke I used might be more
than 3 bucks today, and back then transistors were more expensive.


http://www.learningelectronics.net/circuits/simple-am-transmitter.html

http://www.bowdenshobbycircuits.info/page6.htm#amtrans.gif

http://www.zen22142.zen.co.uk/Circuits/rf/amtx.htm

http://www.circuitstoday.com/am-transmitter-circuit

Thanks.

A mic isn't necessary -- just a tone to warn motorists that a cyclist is around the curve.

Radio amateurs, back in the heyday of home-brew, would make little AM
transmitters operating from batteries so they could have "hidden
transmitter hunts," with home-brew radio direction finding rigs.

The government still does the same things - on an industrial scale. I
suspect they are using angle of arrival and time of flight to achieve
the same thing fancy antennas alone used to do. (that's based on
their abandoning the large circular antenna arrays that used to do the
same thing, called a Wullenweber array)

https://www.google.com/search?lr=&as_qdr=all&q=wullenweber&tbm=isch&source=univ&sa=X&ved=2ahUKEwjuuN_khdHmAhWvct8KHecmDyQQsAR6BAgHEAE&biw=1024&bih=646

https://tinyurl.com/tg46nua


they could just be using movable beam antennas like amateurs do,

--
Jasen.

Bret Cahill
Guest

Thu Dec 26, 2019 7:34 pm   



Quote:
Everything on Ebay seems to be more than $3.

AM broadcast band? Chances are if you had to buy all new parts and
build it yourself you'd spend more than $3.

I built those in the 50's. The 3.5 mhy choke I used might be more
than 3 bucks today, and back then transistors were more expensive.


http://www.learningelectronics.net/circuits/simple-am-transmitter.html

http://www.bowdenshobbycircuits.info/page6.htm#amtrans.gif

http://www.zen22142.zen.co.uk/Circuits/rf/amtx.htm

http://www.circuitstoday.com/am-transmitter-circuit

Thanks.

A mic isn't necessary -- just a tone to warn motorists that a cyclist is around the curve.

So why use AM, why not BLE?


I thought high frequencies wouldn't go around buildings, rock cliffs on curves and through thickets of trees like lower frequencies. The engineer at the FCC seemed enthusiastic about AM.

As many motorists have smart phones as AM radios so, if it can be made to work, it might be just as easy to implement. Then you could listen to the radio and get cyclist alerts on the PDA at the same time.

My niece-in-law just got a bicycle for Christmas. She suggested something more sophisticated than binary, an indication of distance. Maybe several beacons or several different frequencies on the cyclist could provide location info to motorists.

It's really critical to know which lane the cyclist is in on "California Historical Highways" -- one mistake and yer history. All California is doing now is putting up "Share the Road" and cardboard "3' clearance is the law" signs which is almost insulting.

It may be easier to get some N. European country to do this first. I've got exactly zero pull in Sacramento.


Bret Cahill

default
Guest

Thu Dec 26, 2019 8:24 pm   



On Wed, 25 Dec 2019 19:43:00 -0000 (UTC), Jasen Betts
<jasen_at_xnet.co.nz> wrote:

Quote:
On 2019-12-25, default <default_at_defaulter.neo> wrote:
On Mon, 23 Dec 2019 08:59:58 -0800 (PST), Bret Cahill
bretcahill_at_aol.com> wrote:

Everything on Ebay seems to be more than $3.

AM broadcast band? Chances are if you had to buy all new parts and
build it yourself you'd spend more than $3.

I built those in the 50's. The 3.5 mhy choke I used might be more
than 3 bucks today, and back then transistors were more expensive.


http://www.learningelectronics.net/circuits/simple-am-transmitter.html

http://www.bowdenshobbycircuits.info/page6.htm#amtrans.gif

http://www.zen22142.zen.co.uk/Circuits/rf/amtx.htm

http://www.circuitstoday.com/am-transmitter-circuit

Thanks.

A mic isn't necessary -- just a tone to warn motorists that a cyclist is around the curve.

Radio amateurs, back in the heyday of home-brew, would make little AM
transmitters operating from batteries so they could have "hidden
transmitter hunts," with home-brew radio direction finding rigs.

The government still does the same things - on an industrial scale. I
suspect they are using angle of arrival and time of flight to achieve
the same thing fancy antennas alone used to do. (that's based on
their abandoning the large circular antenna arrays that used to do the
same thing, called a Wullenweber array)

https://www.google.com/search?lr=&as_qdr=all&q=wullenweber&tbm=isch&source=univ&sa=X&ved=2ahUKEwjuuN_khdHmAhWvct8KHecmDyQQsAR6BAgHEAE&biw=1024&bih=646

https://tinyurl.com/tg46nua

they could just be using movable beam antennas like amateurs do,


Not the way they do it. They have a radar type display and used a
goniometer to "give rotating properties to stationary antennas" and
had excellent triangulation accuracy. Several operators could sit at
consoles and monitor different frequencies with the same system in
real time. The op would just position the curser on the signal and
read out the bearing. Speed and accuracy count when you are dealing
with search and rescue, etc..

Those amateur antenna were only suitable for a single, relatively high
frequency, and didn't have globe-spanning accuracy. A high tech game
of hide and seek. The transmitters were disguised and put in hard to
reach places, so you couldn't just drive right to them.

Jasen Betts
Guest

Fri Dec 27, 2019 12:20 am   



On 2019-12-26, Bret Cahill <bretcahill_at_aol.com> wrote:
Quote:

Everything on Ebay seems to be more than $3.

AM broadcast band? Chances are if you had to buy all new parts and
build it yourself you'd spend more than $3.

I built those in the 50's. The 3.5 mhy choke I used might be more
than 3 bucks today, and back then transistors were more expensive.


http://www.learningelectronics.net/circuits/simple-am-transmitter.html

http://www.bowdenshobbycircuits.info/page6.htm#amtrans.gif

http://www.zen22142.zen.co.uk/Circuits/rf/amtx.htm

http://www.circuitstoday.com/am-transmitter-circuit

Thanks.

A mic isn't necessary -- just a tone to warn motorists that a cyclist is around the curve.

So why use AM, why not BLE?

I thought high frequencies wouldn't go around buildings, rock cliffs
on curves and through thickets of trees like lower frequencies.


that's a good point.

> As many motorists have smart phones as AM radios so, if it can be made to work, it might be just as easy to implement. Then you could listen to the radio and get cyclist alerts on the PDA at the same time.

I've not seen any smart phones that could receive AM.
and none that could receive FM without an external antenna.

Quote:
My niece-in-law just got a bicycle for Christmas. She suggested
something more sophisticated than binary, an indication of distance.
Maybe several beacons or several different frequencies on the cyclist
could provide location info to motorists.


they do something similar with aircraft.

Be aware that this will also be applied to pets and pedestrians,
because people are selfish.

Quote:
It's really critical to know which lane the cyclist is in on
"California Historical Highways" -- one mistake and yer history. All
California is doing now is putting up "Share the Road" and cardboard
"3' clearance is the law" signs which is almost insulting.


Insulting to who? the aluminium smelters who voted for trump?

> It may be easier to get some N. European country to do this first. I've got exactly zero pull in Sacramento.

The simplest fix for invisible cyclists is to reduce speed
until the become sufficiently visible, next simplest is
separate roads for cyclists.

Traffic networking (which this seems a precursor to) is still a way in
the future.


--
Jasen.

Bret Cahill
Guest

Fri Dec 27, 2019 7:11 am   



Quote:
Everything on Ebay seems to be more than $3.

AM broadcast band? Chances are if you had to buy all new parts and
build it yourself you'd spend more than $3.

I built those in the 50's. The 3.5 mhy choke I used might be more
than 3 bucks today, and back then transistors were more expensive.


http://www.learningelectronics.net/circuits/simple-am-transmitter.html

http://www.bowdenshobbycircuits.info/page6.htm#amtrans.gif

http://www.zen22142.zen.co.uk/Circuits/rf/amtx.htm

http://www.circuitstoday.com/am-transmitter-circuit

Thanks.

A mic isn't necessary -- just a tone to warn motorists that a cyclist is around the curve.

So why use AM, why not BLE?

I thought high frequencies wouldn't go around buildings, rock cliffs
on curves and through thickets of trees like lower frequencies.

that's a good point.

As many motorists have smart phones as AM radios so, if it can be made to work, it might be just as easy to implement. Then you could listen to the radio and get cyclist alerts on the PDA at the same time.

I've not seen any smart phones that could receive AM.
and none that could receive FM without an external antenna.


That would be for a Bluetooth version.

Quote:
My niece-in-law just got a bicycle for Christmas. She suggested
something more sophisticated than binary, an indication of distance.
Maybe several beacons or several different frequencies on the cyclist
could provide location info to motorists.

they do something similar with aircraft.


You get more fatalities cycling than flying. I've been sideswiped twice at freeway speeds and once in an intersection trying to stay out from under the tires.

Nothing like that has ever happened flying. Of course, I cycle more than I fly . . .

Quote:
Be aware that this will also be applied to pets and pedestrians,
because people are selfish.


Motorcyclists could use it as well.

Quote:
It's really critical to know which lane the cyclist is in on
"California Historical Highways" -- one mistake and yer history. All
California is doing now is putting up "Share the Road" and cardboard
"3' clearance is the law" signs which is almost insulting.

Insulting to who?


Cyclists.

Quote:
the aluminium smelters who voted for trump?

It may be easier to get some N. European country to do this first. I've got exactly zero pull in Sacramento.

The simplest fix for invisible cyclists is to reduce speed
until the become sufficiently visible,


Motorists won't reduce speed.

Quote:
next simplest is
separate roads for cyclists.


That's very very expensive, politically impossible.

Quote:
Traffic networking (which this seems a precursor to) is still a way in
the future.


They could do it almost overnight. The lowest of the low hanging fruit.


Bret Cahill

Jasen Betts
Guest

Fri Dec 27, 2019 1:06 pm   



On 2019-12-27, Bret Cahill <bretcahill_at_aol.com> wrote:
Quote:
Everything on Ebay seems to be more than $3.

AM broadcast band? Chances are if you had to buy all new parts and
build it yourself you'd spend more than $3.

I built those in the 50's. The 3.5 mhy choke I used might be more
than 3 bucks today, and back then transistors were more expensive.


http://www.learningelectronics.net/circuits/simple-am-transmitter.html

http://www.bowdenshobbycircuits.info/page6.htm#amtrans.gif

http://www.zen22142.zen.co.uk/Circuits/rf/amtx.htm

http://www.circuitstoday.com/am-transmitter-circuit

Thanks.

A mic isn't necessary -- just a tone to warn motorists that a cyclist is around the curve.

So why use AM, why not BLE?

I thought high frequencies wouldn't go around buildings, rock cliffs
on curves and through thickets of trees like lower frequencies.

that's a good point.

As many motorists have smart phones as AM radios so, if it can be made to work, it might be just as easy to implement. Then you could listen to the radio and get cyclist alerts on the PDA at the same time.

I've not seen any smart phones that could receive AM.
and none that could receive FM without an external antenna.

That would be for a Bluetooth version.

My niece-in-law just got a bicycle for Christmas. She suggested
something more sophisticated than binary, an indication of distance.
Maybe several beacons or several different frequencies on the cyclist
could provide location info to motorists.

they do something similar with aircraft.

You get more fatalities cycling than flying. I've been sideswiped twice at freeway speeds and once in an intersection trying to stay out from under the tires.

Nothing like that has ever happened flying. Of course, I cycle more than I fly . . .

Be aware that this will also be applied to pets and pedestrians,
because people are selfish.

Motorcyclists could use it as well.

It's really critical to know which lane the cyclist is in on
"California Historical Highways" -- one mistake and yer history. All
California is doing now is putting up "Share the Road" and cardboard
"3' clearance is the law" signs which is almost insulting.

Insulting to who?

Cyclists.


Where is the insult?

Quote:
It may be easier to get some N. European country to do this first. I've got exactly zero pull in Sacramento.

The simplest fix for invisible cyclists is to reduce speed
until the become sufficiently visible,

Motorists won't reduce speed.


Driving at unsafe speed is legal? it sounds like you have an
enforcement problem there.

Quote:
next simplest is
separate roads for cyclists.

That's very very expensive, politically impossible.

Traffic networking (which this seems a precursor to) is still a way in
the future.

They could do it almost overnight. The lowest of the low hanging fruit.


So I'm driving along listening to spotify, and what happens?

--
Jasen.

Ralph Mowery
Guest

Fri Dec 27, 2019 8:39 pm   



In article <qu4okj$k6o$2_at_gonzo.revmaps.no-ip.org>, jasen_at_xnet.co.nz
says...
Quote:

Motorists won't reduce speed.

Driving at unsafe speed is legal? it sounds like you have an
enforcement problem there.




The cycle riders should be able to make the speed limit on the highways.
Should have tags and insurance if over 18.

While at it, another pet peeve of mine is those slow mopeds.

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