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Antenna rotators for loop antennas


Chris Moulding
 

The price of "ham radio antenna rotators" has gone through the roof in the last few years.

I did a quick search on eBay and came up with a lot of CCTV pan/tilt units and controllers using RS-485 wire control.

The pan/tilt units usually rotate 255 degrees which is OK for a loop antenna. They go for £8 to £15 ($10.50 to $19.50) for an indoor version or around £19 ($24.70) for an outdoor version. They are rated for 1.5 kg load so a light bicycle wheel rim loop should be OK. It needs 12V and two control wires connecting to it.

https://www.ebay.co.uk/itm/Outdoor-Electric-Bracket-Pan-Tilt-RS485-Control-Mount-Security-CCTV-Camera-Stand/183920327943?hash=item2ad2817d07:g:U0MAAOSwstxVJ4sh

They can be used with a RS-485 CCTV controller with a joystick or keyboard which sells for typically £36 ($46.80). The controller can control up to 200 cameras or loop antennas.

https://www.ebay.co.uk/itm/3D-Pan-Tilt-PTZ-Zoom-Controller-Joystick-Keyboard-RS-485-for-CCTV-Camera-DVR/112686152483?_trksid=p2485497.m4902.l9144

Obviously I've not tried one yet but it could be a workable solution for a light loop antenna.

Regards,

Chris


Martin - G8JNJ
 

Hi Chris,

A cheaper option for control is to buy a USB to RS485 dongle and use one of the many free PTZ controller apps for the PC (or write your own).

Here's a couple of examples

https://www.amazon.co.uk/WINGONEER-USB-485-Converter-Adapter-Window-1/dp/B016IG6X7I/ref=sr_1_8?keywords=usb+to+rs485+cable&qid=1575461769&sr=8-8

https://download.cnet.com/PTZ-Controller/3000-2653_4-10810761.html

It could perhaps also be used for satellite tracking with a lightweight beam.

Sounds like a good project :-)

Regards,

Martin - G8JNJ


Tom Crosbie G6PZZ
 

Just to add a different slant (pun intended – sorry!) to this, I’ve got a PTZ camera on its way from China, combined with an order for a nanoVNA. I thought I could use the camera mount to point and tilt a loop antenna. I have a cylindrical box from a bottle of single malt (another hobby) and I intend to wind a coil or coils around this and see what happens. Somewhere around there is a formula involving coil diameter, size of wire, number of turns and impedance which I will have to find. If it turns out the tube’s diameter is wrong, I’ll just have to buy other bottles until I get it right! This could affect getting the number of turns correct…

 

Tom G6PZZ  

 

From: CrossCountryWireless@groups.io <CrossCountryWireless@groups.io> On Behalf Of Martin - G8JNJ via Groups.Io
Sent: 04 December 2019 12:18
To: CrossCountryWireless@groups.io
Subject: Re: [CrossCountryWireless] Antenna rotators for loop antennas

 

Hi Chris,

A cheaper option for control is to buy a USB to RS485 dongle and use one of the many free PTZ controller apps for the PC (or write your own).

Here's a couple of examples

https://www.amazon.co.uk/WINGONEER-USB-485-Converter-Adapter-Window-1/dp/B016IG6X7I/ref=sr_1_8?keywords=usb+to+rs485+cable&qid=1575461769&sr=8-8

https://download.cnet.com/PTZ-Controller/3000-2653_4-10810761.html

It could perhaps also be used for satellite tracking with a lightweight beam.

Sounds like a good project :-)

Regards,

Martin - G8JNJ


Oene Spoelstra
 

Just imagine... I 've got a store loaded with that kind of cylinders filled with bottles of whisky.

Op wo 4 dec. 2019 20:45 schreef Tom Crosbie G6PZZ <tom@...>:

Just to add a different slant (pun intended – sorry!) to this, I’ve got a PTZ camera on its way from China, combined with an order for a nanoVNA. I thought I could use the camera mount to point and tilt a loop antenna. I have a cylindrical box from a bottle of single malt (another hobby) and I intend to wind a coil or coils around this and see what happens. Somewhere around there is a formula involving coil diameter, size of wire, number of turns and impedance which I will have to find. If it turns out the tube’s diameter is wrong, I’ll just have to buy other bottles until I get it right! This could affect getting the number of turns correct…

 

Tom G6PZZ  

 

From: CrossCountryWireless@groups.io <CrossCountryWireless@groups.io> On Behalf Of Martin - G8JNJ via Groups.Io
Sent: 04 December 2019 12:18
To: CrossCountryWireless@groups.io
Subject: Re: [CrossCountryWireless] Antenna rotators for loop antennas

 

Hi Chris,

A cheaper option for control is to buy a USB to RS485 dongle and use one of the many free PTZ controller apps for the PC (or write your own).

Here's a couple of examples

https://www.amazon.co.uk/WINGONEER-USB-485-Converter-Adapter-Window-1/dp/B016IG6X7I/ref=sr_1_8?keywords=usb+to+rs485+cable&qid=1575461769&sr=8-8

https://download.cnet.com/PTZ-Controller/3000-2653_4-10810761.html

It could perhaps also be used for satellite tracking with a lightweight beam.

Sounds like a good project :-)

Regards,

Martin - G8JNJ


Chris Moulding
 

Oene, I would ask you to measure the whisky cylinders but it would spoil Tom's fun!

Here is the best coil inductance calculator I've found:

https://hamwaves.com/inductance/en/index.html#input

Regards,

Chris


Tom Crosbie G6PZZ
 

Chris,

Everybody knows you should only measure the box AFTER the whisky has been consumed. It would otherwise jinx the whole experiment.

On a slightly more serious note I have a two-gang air spaced variable capacitor that fits inside the tube and will attach to one of the tin stoppers that are at each end. There is also a large empty space inside that could be filled with ferrite. (I have enough random Chinese ferrite!)

I would hope for a varicap solution later so I could fix the antenna and PTZ mount on the ceiling, or on a windowsill.

Another experiment could involve one of your loop amps Chris but that would probably need a much smaller amp box though (uncased version?)or a much bigger whisky box. (Any suggestions Oene?)  

I made a mistake on that calculator Chris. I started reading the FAQ and got lost on the first paragraph. The site looks fascinating though and I haven’t seen it before.

Cheers

Tom G6PZZ  

 

From: CrossCountryWireless@groups.io <CrossCountryWireless@groups.io> On Behalf Of Chris Moulding
Sent: 04 December 2019 20:05
To: CrossCountryWireless@groups.io
Subject: Re: [CrossCountryWireless] Antenna rotators for loop antennas

 

Oene, I would ask you to measure the whisky cylinders but it would spoil Tom's fun!

Here is the best coil inductance calculator I've found:

https://hamwaves.com/inductance/en/index.html#input

Regards,

Chris


Oene Spoelstra
 

Perhaps a barrel ?

Op wo 4 dec. 2019 22:15 schreef Tom Crosbie G6PZZ <tom@...>:

Chris,

Everybody knows you should only measure the box AFTER the whisky has been consumed. It would otherwise jinx the whole experiment.

On a slightly more serious note I have a two-gang air spaced variable capacitor that fits inside the tube and will attach to one of the tin stoppers that are at each end. There is also a large empty space inside that could be filled with ferrite. (I have enough random Chinese ferrite!)

I would hope for a varicap solution later so I could fix the antenna and PTZ mount on the ceiling, or on a windowsill.

Another experiment could involve one of your loop amps Chris but that would probably need a much smaller amp box though (uncased version?)or a much bigger whisky box. (Any suggestions Oene?)  

I made a mistake on that calculator Chris. I started reading the FAQ and got lost on the first paragraph. The site looks fascinating though and I haven’t seen it before.

Cheers

Tom G6PZZ  

 

From: CrossCountryWireless@groups.io <CrossCountryWireless@groups.io> On Behalf Of Chris Moulding
Sent: 04 December 2019 20:05
To: CrossCountryWireless@groups.io
Subject: Re: [CrossCountryWireless] Antenna rotators for loop antennas

 

Oene, I would ask you to measure the whisky cylinders but it would spoil Tom's fun!

Here is the best coil inductance calculator I've found:

https://hamwaves.com/inductance/en/index.html#input

Regards,

Chris