One-off special...Indoor HF Active Loop antenna


Chris Moulding
 

Sometimes we are asked to do one-off versions of our products for special applications, very often it helps push the development of our products into new areas.

Recently I was asked by a short wave listener who only lives a few miles from us if we could build an indoor version of our HF Active Loop antenna. It's not possible for him to erect outdoor antennas but he still wants an antenna that can hear DX and non directional beacons around 300 kHz.

It's an interesting challenge on two fronts. First it has too look good for indoor use so two separate boxes and ethernet cable connection were out and it has to have some form of flat mount to fit on a table. All the amplifier and power filtering was fitted into what would usually be the head unit and I sourced a rather nice oak plinth usually used for making trophies as a base.

The second challenge was even tougher. The standard loop antenna we make at present rolls off at 500 kHz. I used a revised circuit made for another "special" loop antenna but changed the biasing arrangement so that it would work better at low frequencies. I overdid it a bit as I can now hear the VLF submarine transmission from the Anthorn radio station in north west England on 22.1 kHz with the loop. To allow it to be used indoors I added a common mode filter to the antenna input to stop the loop acting as an electric field probe picking up RF noise from the house electrical system. I adder extra common mode filters to the DC input and RF output to further isolate the antenna from noise.

Testing it on HF shows that it will receive DX as ordered. Yesterday evening I was doing comparison tests with a Terminated Inverted U antenna (the lowest noise antenna here so far) on the 80m amateur band and the loop out-performed it even though it was mounted indoors next to two computers.

The improved loop amplifier design is now going to be added to the existing HF Active Loop antenna extending the frequency coverage from 20 kHz to 70 MHz with a dipole loop pattern and multilobe pattern up to 148 MHz.

Unfortunately the indoor version is likely to remain a one-off as I can no longer source a RF quiet linear 12V power supply due to EU regulations outlawing them replacing them with switch mode power supplies in the quest for power efficiency. Every switch mode power supply I've tried generates too much noise even with the common mode filters added to the antenna amplifier. I'm supplying the last of my stock of linear power supplies with it.

Here are some photos of the antenna taken today before it's delivered to the customer tomorrow.



Regards,

Chris


Graham J Smith G4NMD
 

But.... if one could supply ones own non-noisy supply.....

I had a long association with Anthorn, Inskip, Rugby and acrimony

Graham NMD


On 26 Sep 2018, at 21:12, Chris Moulding <chrism@...> wrote:

Sometimes we are asked to do one-off versions of our products for special applications, very often it helps push the development of our products into new areas.

Recently I was asked by a short wave listener who only lives a few miles from us if we could build an indoor version of our HF Active Loop antenna. It's not possible for him to erect outdoor antennas but he still wants an antenna that can hear DX and non directional beacons around 300 kHz.

It's an interesting challenge on two fronts. First it has too look good for indoor use so two separate boxes and ethernet cable connection were out and it has to have some form of flat mount to fit on a table. All the amplifier and power filtering was fitted into what would usually be the head unit and I sourced a rather nice oak plinth usually used for making trophies as a base.

The second challenge was even tougher. The standard loop antenna we make at present rolls off at 500 kHz. I used a revised circuit made for another "special" loop antenna but changed the biasing arrangement so that it would work better at low frequencies. I overdid it a bit as I can now hear the VLF submarine transmission from the Anthorn radio station in north west England on 22.1 kHz with the loop. To allow it to be used indoors I added a common mode filter to the antenna input to stop the loop acting as an electric field probe picking up RF noise from the house electrical system. I adder extra common mode filters to the DC input and RF output to further isolate the antenna from noise.

Testing it on HF shows that it will receive DX as ordered. Yesterday evening I was doing comparison tests with a Terminated Inverted U antenna (the lowest noise antenna here so far) on the 80m amateur band and the loop out-performed it even though it was mounted indoors next to two computers.

The improved loop amplifier design is now going to be added to the existing HF Active Loop antenna extending the frequency coverage from 20 kHz to 70 MHz with a dipole loop pattern and multilobe pattern up to 148 MHz.

Unfortunately the indoor version is likely to remain a one-off as I can no longer source a RF quiet linear 12V power supply due to EU regulations outlawing them replacing them with switch mode power supplies in the quest for power efficiency. Every switch mode power supply I've tried generates too much noise even with the common mode filters added to the antenna amplifier. I'm supplying the last of my stock of linear power supplies with it.

Here are some photos of the antenna taken today before it's delivered to the customer tomorrow.

<Indoor_active_loop1.jpg><Indoor_active_loop2.jpg>

Regards,

Chris


Graham J Smith G4NMD
 

Damn spell check it was Crimond not acrimony


On 26 Sep 2018, at 21:56, Graham J Smith G4NMD <gjsmith@...> wrote:

But.... if one could supply ones own non-noisy supply.....

I had a long association with Anthorn, Inskip, Rugby and acrimony

Graham NMD


On 26 Sep 2018, at 21:12, Chris Moulding <chrism@...> wrote:

Sometimes we are asked to do one-off versions of our products for special applications, very often it helps push the development of our products into new areas.

Recently I was asked by a short wave listener who only lives a few miles from us if we could build an indoor version of our HF Active Loop antenna. It's not possible for him to erect outdoor antennas but he still wants an antenna that can hear DX and non directional beacons around 300 kHz.

It's an interesting challenge on two fronts. First it has too look good for indoor use so two separate boxes and ethernet cable connection were out and it has to have some form of flat mount to fit on a table. All the amplifier and power filtering was fitted into what would usually be the head unit and I sourced a rather nice oak plinth usually used for making trophies as a base.

The second challenge was even tougher. The standard loop antenna we make at present rolls off at 500 kHz. I used a revised circuit made for another "special" loop antenna but changed the biasing arrangement so that it would work better at low frequencies. I overdid it a bit as I can now hear the VLF submarine transmission from the Anthorn radio station in north west England on 22.1 kHz with the loop. To allow it to be used indoors I added a common mode filter to the antenna input to stop the loop acting as an electric field probe picking up RF noise from the house electrical system. I adder extra common mode filters to the DC input and RF output to further isolate the antenna from noise.

Testing it on HF shows that it will receive DX as ordered. Yesterday evening I was doing comparison tests with a Terminated Inverted U antenna (the lowest noise antenna here so far) on the 80m amateur band and the loop out-performed it even though it was mounted indoors next to two computers.

The improved loop amplifier design is now going to be added to the existing HF Active Loop antenna extending the frequency coverage from 20 kHz to 70 MHz with a dipole loop pattern and multilobe pattern up to 148 MHz.

Unfortunately the indoor version is likely to remain a one-off as I can no longer source a RF quiet linear 12V power supply due to EU regulations outlawing them replacing them with switch mode power supplies in the quest for power efficiency. Every switch mode power supply I've tried generates too much noise even with the common mode filters added to the antenna amplifier. I'm supplying the last of my stock of linear power supplies with it.

Here are some photos of the antenna taken today before it's delivered to the customer tomorrow.

<Indoor_active_loop1.jpg><Indoor_active_loop2.jpg>

Regards,

Chris


Chris Moulding
 

Hi Graham,

I've had a few suggestions already about supplying your own supply so I might be persuaded to make a few more.

Whenever I mention VLF in the forum or on the Facebook page I'm always surprised at the amount of interest in it and the number of people who have had a professional interest in it.

Regards,

Chris G4HYG

--
Chris Moulding
Cross Country Wireless
7 Thirlmere Grove, Bolton, Lancs, BL4 0QB, UK
Tel/fax: +44(0)1204 410626
Mob/workshop: +44(0)7752 391908
Secure email: g4hyg@protonmail.com
Website: http://www.crosscountrywireless.net
Groups.io: https://groups.io/g/CrossCountryWireless

On 26/09/18 21:56, Graham J Smith G4NMD wrote:
But.... if one could supply ones own non-noisy supply.....
I had a long association with Anthorn, Inskip, Rugby and acrimony
Graham NMD
On 26 Sep 2018, at 21:12, Chris Moulding <chrism@crosscountrywireless.net <mailto:chrism@crosscountrywireless.net>> wrote:

Sometimes we are asked to do one-off versions of our products for special applications, very often it helps push the development of our products into new areas.

Recently I was asked by a short wave listener who only lives a few miles from us if we could build an indoor version of our HF Active Loop antenna. It's not possible for him to erect outdoor antennas but he still wants an antenna that can hear DX and non directional beacons around 300 kHz.

It's an interesting challenge on two fronts. First it has too look good for indoor use so two separate boxes and ethernet cable connection were out and it has to have some form of flat mount to fit on a table. All the amplifier and power filtering was fitted into what would usually be the head unit and I sourced a rather nice oak plinth usually used for making trophies as a base.

The second challenge was even tougher. The standard loop antenna we make at present rolls off at 500 kHz. I used a revised circuit made for another "special" loop antenna but changed the biasing arrangement so that it would work better at low frequencies. I overdid it a bit as I can now hear the VLF submarine transmission from the Anthorn radio station in north west England on 22.1 kHz with the loop. To allow it to be used indoors I added a common mode filter to the antenna input to stop the loop acting as an electric field probe picking up RF noise from the house electrical system. I adder extra common mode filters to the DC input and RF output to further isolate the antenna from noise.

Testing it on HF shows that it will receive DX as ordered. Yesterday evening I was doing comparison tests with a Terminated Inverted U antenna (the lowest noise antenna here so far) on the 80m amateur band and the loop out-performed it even though it was mounted indoors next to two computers.

The improved loop amplifier design is now going to be added to the existing HF Active Loop antenna extending the frequency coverage from 20 kHz to 70 MHz with a dipole loop pattern and multilobe pattern up to 148 MHz.

Unfortunately the indoor version is likely to remain a one-off as I can no longer source a RF quiet linear 12V power supply due to EU regulations outlawing them replacing them with switch mode power supplies in the quest for power efficiency. Every switch mode power supply I've tried generates too much noise even with the common mode filters added to the antenna amplifier. I'm supplying the last of my stock of linear power supplies with it.

Here are some photos of the antenna taken today before it's delivered to the customer tomorrow.

<Indoor_active_loop1.jpg><Indoor_active_loop2.jpg>

Regards,

Chris


David Cutter
 

Well done, Chris. 

 

Two things come to mind: when you say it out-performed the inverted U, I imagine you mean it was quieter, however do you mean that you could hear signals not heard on the inverted U?

 

Re power supplies: for the ultimate in quiet listening there's always the option of batteries in an outboard cassette, such as the re-chargeable LiIon which I can now get it in a neat 12V package.  There's always the option of using the shack linear dc supply.

 

Very many folks have unbelievably noisy local environments making communications unworkable from home; but with a quiet receive system it makes it perfectly possible to have meaningful communications if the transceiver can handle 2 antennas.  I built a changeover antenna switch for a friend whose radio has only one antenna socket, perhaps you could make such a unit to accompany your quiet receive systems.

 

I can imagine using an inverted U for tx and rx, then this receive-only antenna as the other, perhaps on a small TV rotator. 

 

David G3UNA

 

From: CrossCountryWireless@groups.io [mailto:CrossCountryWireless@groups.io] On Behalf Of Chris Moulding
Sent: 26 September 2018 21:12
To: CrossCountryWireless@groups.io
Subject: [CrossCountryWireless] One-off special...Indoor HF Active Loop antenna

 

Sometimes we are asked to do one-off versions of our products for special applications, very often it helps push the development of our products into new areas.

Recently I was asked by a short wave listener who only lives a few miles from us if we could build an indoor version of our HF Active Loop antenna. It's not possible for him to erect outdoor antennas but he still wants an antenna that can hear DX and non directional beacons around 300 kHz.

It's an interesting challenge on two fronts. First it has too look good for indoor use so two separate boxes and ethernet cable connection were out and it has to have some form of flat mount to fit on a table. All the amplifier and power filtering was fitted into what would usually be the head unit and I sourced a rather nice oak plinth usually used for making trophies as a base.

The second challenge was even tougher. The standard loop antenna we make at present rolls off at 500 kHz. I used a revised circuit made for another "special" loop antenna but changed the biasing arrangement so that it would work better at low frequencies. I overdid it a bit as I can now hear the VLF submarine transmission from the Anthorn radio station in north west England on 22.1 kHz with the loop. To allow it to be used indoors I added a common mode filter to the antenna input to stop the loop acting as an electric field probe picking up RF noise from the house electrical system. I adder extra common mode filters to the DC input and RF output to further isolate the antenna from noise.

Testing it on HF shows that it will receive DX as ordered. Yesterday evening I was doing comparison tests with a Terminated Inverted U antenna (the lowest noise antenna here so far) on the 80m amateur band and the loop out-performed it even though it was mounted indoors next to two computers.

The improved loop amplifier design is now going to be added to the existing HF Active Loop antenna extending the frequency coverage from 20 kHz to 70 MHz with a dipole loop pattern and multilobe pattern up to 148 MHz.

Unfortunately the indoor version is likely to remain a one-off as I can no longer source a RF quiet linear 12V power supply due to EU regulations outlawing them replacing them with switch mode power supplies in the quest for power efficiency. Every switch mode power supply I've tried generates too much noise even with the common mode filters added to the antenna amplifier. I'm supplying the last of my stock of linear power supplies with it.

Here are some photos of the antenna taken today before it's delivered to the customer tomorrow.



Regards,

Chris


david
 

An HF active antenna that manages a good s/n ratio at LF would be greatly appreciated.
The bigger problem appears to be sourcing that 'TV Rotator'. If you only need to turn a small loop like the CCW antenna, all the rotators on today's market are over-specified and expensive.

David, GM8XBZ

-----Original Message-----
From: CrossCountryWireless@groups.io <CrossCountryWireless@groups.io> On Behalf Of David Cutter via Groups.Io
Sent: 27 September 2018 10:59
To: CrossCountryWireless@groups.io
Subject: Re: [CrossCountryWireless] One-off special...Indoor HF Active Loop antenna

Well done, Chris.

<snip>

I can imagine using an inverted U for tx and rx, then this receive-only antenna as the other, perhaps on a small TV rotator.


Greg_2e1gw
 

With regards to rotators...  The only one I could find that was a TV type and cheaper was on a well known internet auction site.  It had to come from the US, but the company had signed up for the scheme where the postage covers all the p&p, customs and vat duty etc so you didn't have the performance getting it into the country.  It was a Channel Master 9521.  Think it was around £142 all in compared to silly cash for ham brands, although not as good as the £80 you used to be able to pay.
Best wishes
Greg
M6ORT 


From: CrossCountryWireless@groups.io <CrossCountryWireless@groups.io> on behalf of david via Groups.Io <zinc65@...>
Sent: 27 September 2018 12:40
To: CrossCountryWireless@groups.io
Subject: Re: [CrossCountryWireless] One-off special...Indoor HF Active Loop antenna
 
An HF active antenna that manages a good s/n ratio at LF would be greatly appreciated.
The bigger problem appears to be sourcing that 'TV Rotator'. If you only need to turn a small loop like the CCW antenna, all the rotators on today's market are over-specified and expensive.

David, GM8XBZ

-----Original Message-----
From: CrossCountryWireless@groups.io <CrossCountryWireless@groups.io> On Behalf Of David Cutter via Groups.Io
Sent: 27 September 2018 10:59
To: CrossCountryWireless@groups.io
Subject: Re: [CrossCountryWireless] One-off special...Indoor HF Active Loop antenna

Well done, Chris. 

<snip>

I can imagine using an inverted U for tx and rx, then this receive-only antenna as the other, perhaps on a small TV rotator. 

 





K4KDR
 

Solid Signal has a number of AZ-only “TV” rotators:
 
 
... in particular, for years I’ve used an earlier version similar to:
 
 
... and it’s even computer-controllable with a USB IR adapter that the PSTRotator software talks to perfectly.
 
The how-to on that is a little out-dated since software versions & product availability change constantly, but if anyone is interested that’s at:
 
 
-Scott,  K4KDR
 
 
======================================
 
 
 

From: Greg_M6ORT
Sent: Thursday, September 27, 2018 9:01 AM
Subject: Re: [CrossCountryWireless] One-off special...Indoor HF Active Loop antenna
 
With regards to rotators...  The only one I could find that was a TV type and cheaper was on a well known internet auction site.  It had to come from the US, but the company had signed up for the scheme where the postage covers all the p&p, customs and vat duty etc so you didn't have the performance getting it into the country.  It was a Channel Master 9521.  Think it was around £142 all in compared to silly cash for ham brands, although not as good as the £80 you used to be able to pay.
Best wishes
Greg
M6ORT 
 

From: CrossCountryWireless@groups.io <CrossCountryWireless@groups.io> on behalf of david via Groups.Io <zinc65@...>
Sent: 27 September 2018 12:40
To: CrossCountryWireless@groups.io
Subject: Re: [CrossCountryWireless] One-off special...Indoor HF Active Loop antenna
 
An HF active antenna that manages a good s/n ratio at LF would be greatly appreciated.
The bigger problem appears to be sourcing that 'TV Rotator'. If you only need to turn a small loop like the CCW antenna, all the rotators on today's market are over-specified and expensive.

David, GM8XBZ

-----Original Message-----
From: CrossCountryWireless@groups.io <CrossCountryWireless@groups.io> On Behalf Of David Cutter via Groups.Io
Sent: 27 September 2018 10:59
To: CrossCountryWireless@groups.io
Subject: Re: [CrossCountryWireless] One-off special...Indoor HF Active Loop antenna

Well done, Chris. 

<snip>

I can imagine using an inverted U for tx and rx, then this receive-only antenna as the other, perhaps on a small TV rotator. 


David Cutter
 

I started to design a small rotator from a BBQ spit rotator.  Amazon has them at around £5. The battery is integral and I think it could be done without much ado.  It is just the business end, no controller or direction indicator.  Should be a great little project for someone with the time…whatever that is. 

David G3UNA

 

From: CrossCountryWireless@groups.io [mailto:CrossCountryWireless@groups.io] On Behalf Of Greg_M6ORT
Sent: 27 September 2018 14:02
To: david via Groups.Io; CrossCountryWireless@groups.io
Subject: Re: [CrossCountryWireless] One-off special...Indoor HF Active Loop antenna

 

With regards to rotators...  The only one I could find that was a TV type and cheaper was on a well known internet auction site.  It had to come from the US, but the company had signed up for the scheme where the postage covers all the p&p, customs and vat duty etc so you didn't have the performance getting it into the country.  It was a Channel Master 9521.  Think it was around £142 all in compared to silly cash for ham brands, although not as good as the £80 you used to be able to pay.

Best wishes

Greg

M6ORT 

 


From: CrossCountryWireless@groups.io <CrossCountryWireless@groups.io> on behalf of david via Groups.Io <zinc65@...>
Sent: 27 September 2018 12:40
To: CrossCountryWireless@groups.io
Subject: Re: [CrossCountryWireless] One-off special...Indoor HF Active Loop antenna

 

An HF active antenna that manages a good s/n ratio at LF would be greatly appreciated.
The bigger problem appears to be sourcing that 'TV Rotator'. If you only need to turn a small loop like the CCW antenna, all the rotators on today's market are over-specified and expensive.

David, GM8XBZ

-----Original Message-----
From: CrossCountryWireless@groups.io <CrossCountryWireless@groups.io> On Behalf Of David Cutter via Groups.Io
Sent: 27 September 2018 10:59
To: CrossCountryWireless@groups.io
Subject: Re: [CrossCountryWireless] One-off special...Indoor HF Active Loop antenna

Well done, Chris. 

<snip>

I can imagine using an inverted U for tx and rx, then this receive-only antenna as the other, perhaps on a small TV rotator. 

 




Tom Crosbie G6PZZ
 

I’ve been experimenting with indoor MW loops, pan and tilt being achieved using a camera tripod so the direction indicator is by eyeball. I wanted to mount the loop further away and use some form of remote control. I found some low-speed (2rpm) high torque motors on eBay that looked very capable. 12V DC in one terminal to go clockwise and the same into another to go backwards. Again direction is by eyeball and the tilt has gone for now! These are twice the price of David’s suggestion so I may go back to the drawing board.

 

But to get back to the PSU, I would advocate selling the antenna without one. I would suggest many readers have the means to cobble something together, or have an 12V underused linear supply. I recently purchased some PCB’s that accommodate some capacitors and an LM78XX. This would be fed from my 12V shack supply giving me a range of lower voltages dictated by the choice of LM78XX.

 

It may be possible to design a circuit that would be suitable and offer as a kit without requiring CE approval, perhaps even a populated PCB. I may be wrong on this so I’m ready to be corrected. My knowledge of approvals is both limited and dated.

 

As to the antenna itself, a lower frequency response would definitely suit my listening requirements and go straight onto my Wishlist.

 

Tom G6PZZ

 

From: CrossCountryWireless@groups.io <CrossCountryWireless@groups.io> On Behalf Of David Cutter via Groups.Io
Sent: 27 September 2018 14:47
To: CrossCountryWireless@groups.io
Subject: Re: [CrossCountryWireless] One-off special...Indoor HF Active Loop antenna

 

I started to design a small rotator from a BBQ spit rotator.  Amazon has them at around £5. The battery is integral and I think it could be done without much ado.  It is just the business end, no controller or direction indicator.  Should be a great little project for someone with the time…whatever that is. 

David G3UNA

 

From: CrossCountryWireless@groups.io [mailto:CrossCountryWireless@groups.io] On Behalf Of Greg_M6ORT
Sent: 27 September 2018 14:02
To: david via Groups.Io; CrossCountryWireless@groups.io
Subject: Re: [CrossCountryWireless] One-off special...Indoor HF Active Loop antenna

 

With regards to rotators...  The only one I could find that was a TV type and cheaper was on a well known internet auction site.  It had to come from the US, but the company had signed up for the scheme where the postage covers all the p&p, customs and vat duty etc so you didn't have the performance getting it into the country.  It was a Channel Master 9521.  Think it was around £142 all in compared to silly cash for ham brands, although not as good as the £80 you used to be able to pay.

Best wishes

Greg

M6ORT 

 


From: CrossCountryWireless@groups.io <CrossCountryWireless@groups.io> on behalf of david via Groups.Io <zinc65@...>
Sent: 27 September 2018 12:40
To: CrossCountryWireless@groups.io
Subject: Re: [CrossCountryWireless] One-off special...Indoor HF Active Loop antenna

 

An HF active antenna that manages a good s/n ratio at LF would be greatly appreciated.
The bigger problem appears to be sourcing that 'TV Rotator'. If you only need to turn a small loop like the CCW antenna, all the rotators on today's market are over-specified and expensive.

David, GM8XBZ

-----Original Message-----
From: CrossCountryWireless@groups.io <CrossCountryWireless@groups.io> On Behalf Of David Cutter via Groups.Io
Sent: 27 September 2018 10:59
To: CrossCountryWireless@groups.io
Subject: Re: [CrossCountryWireless] One-off special...Indoor HF Active Loop antenna

Well done, Chris. 

<snip>

I can imagine using an inverted U for tx and rx, then this receive-only antenna as the other, perhaps on a small TV rotator. 

 



Graham J Smith G4NMD
 

Hear Hear

Graham G4NMD. Wishing hard


On 27 Sep 2018, at 16:35, Tom Crosbie G6PZZ <tom@...> wrote:

I’ve been experimenting with indoor MW loops, pan and tilt being achieved using a camera tripod so the direction indicator is by eyeball. I wanted to mount the loop further away and use some form of remote control. I found some low-speed (2rpm) high torque motors on eBay that looked very capable. 12V DC in one terminal to go clockwise and the same into another to go backwards. Again direction is by eyeball and the tilt has gone for now! These are twice the price of David’s suggestion so I may go back to the drawing board.

 

But to get back to the PSU, I would advocate selling the antenna without one. I would suggest many readers have the means to cobble something together, or have an 12V underused linear supply. I recently purchased some PCB’s that accommodate some capacitors and an LM78XX. This would be fed from my 12V shack supply giving me a range of lower voltages dictated by the choice of LM78XX.

 

It may be possible to design a circuit that would be suitable and offer as a kit without requiring CE approval, perhaps even a populated PCB. I may be wrong on this so I’m ready to be corrected. My knowledge of approvals is both limited and dated.

 

As to the antenna itself, a lower frequency response would definitely suit my listening requirements and go straight onto my Wishlist.

 

Tom G6PZZ

 

From: CrossCountryWireless@groups.io <CrossCountryWireless@groups.io> On Behalf Of David Cutter via Groups.Io
Sent: 27 September 2018 14:47
To: CrossCountryWireless@groups.io
Subject: Re: [CrossCountryWireless] One-off special...Indoor HF Active Loop antenna

 

I started to design a small rotator from a BBQ spit rotator.  Amazon has them at around £5. The battery is integral and I think it could be done without much ado.  It is just the business end, no controller or direction indicator.  Should be a great little project for someone with the time…whatever that is. 

David G3UNA

 

From: CrossCountryWireless@groups.io [mailto:CrossCountryWireless@groups.io] On Behalf Of Greg_M6ORT
Sent: 27 September 2018 14:02
To: david via Groups.Io; CrossCountryWireless@groups.io
Subject: Re: [CrossCountryWireless] One-off special...Indoor HF Active Loop antenna

 

With regards to rotators...  The only one I could find that was a TV type and cheaper was on a well known internet auction site.  It had to come from the US, but the company had signed up for the scheme where the postage covers all the p&p, customs and vat duty etc so you didn't have the performance getting it into the country.  It was a Channel Master 9521.  Think it was around £142 all in compared to silly cash for ham brands, although not as good as the £80 you used to be able to pay.

Best wishes

Greg

M6ORT 

 


From: CrossCountryWireless@groups.io <CrossCountryWireless@groups.io> on behalf of david via Groups.Io <zinc65@...>
Sent: 27 September 2018 12:40
To: CrossCountryWireless@groups.io
Subject: Re: [CrossCountryWireless] One-off special...Indoor HF Active Loop antenna

 

An HF active antenna that manages a good s/n ratio at LF would be greatly appreciated.
The bigger problem appears to be sourcing that 'TV Rotator'. If you only need to turn a small loop like the CCW antenna, all the rotators on today's market are over-specified and expensive.

David, GM8XBZ

-----Original Message-----
From: CrossCountryWireless@groups.io <CrossCountryWireless@groups.io> On Behalf Of David Cutter via Groups.Io
Sent: 27 September 2018 10:59
To: CrossCountryWireless@groups.io
Subject: Re: [CrossCountryWireless] One-off special...Indoor HF Active Loop antenna

Well done, Chris. 

<snip>

I can imagine using an inverted U for tx and rx, then this receive-only antenna as the other, perhaps on a small TV rotator. 

 



Adrian Rawlings
 

How about building the equivalent of an goniometer, such that the antenna doesn't have to rotate?

You could do it 'old school' by having two antennas mounted at right angles, which feed two coils which are also at right angles.

Then, use a pick-up coil mounted in the field of these two coils and which is capable of rotating, such that it can be adjusted to pick up suitable portions from the two driving coils. This kind of arrangement is used with DF loops on ships and aircraft.


Chris Moulding
 

Following the interest shown in the indoor version of the loop antenna both on the forum and by direct email I've priced up a small batch of antennas made to the same specification as the one shown in the photographs.

For customers in the UK and Europe the price is £130.00 including shipping plus VAT making a total of £158.00. For international customers including the United States the price including shipping is $200.00.

I'll prepare a web page with more information and PayPal buttons tomorrow. I'll post a link to the new web page when it's ready.

Regards,

Chris


Tom Crosbie G6PZZ
 

That’s fantastic news Chris.

 

Is  there anything else we can bully you into whilst we are on a roll…?

 

Tom G6PZZ

 

From: CrossCountryWireless@groups.io <CrossCountryWireless@groups.io> On Behalf Of Chris Moulding
Sent: 27 September 2018 18:58
To: CrossCountryWireless@groups.io
Subject: Re: [CrossCountryWireless] One-off special...Indoor HF Active Loop antenna

 

Following the interest shown in the indoor version of the loop antenna both on the forum and by direct email I've priced up a small batch of antennas made to the same specification as the one shown in the photographs.

For customers in the UK and Europe the price is £130.00 including shipping plus VAT making a total of £158.00. For international customers including the United States the price including shipping is $200.00.

I'll prepare a web page with more information and PayPal buttons tomorrow. I'll post a link to the new web page when it's ready.

Regards,

Chris


Graham J Smith G4NMD
 

Brilliant

Graham


On 27 Sep 2018, at 18:58, Chris Moulding <chrism@...> wrote:

Following the interest shown in the indoor version of the loop antenna both on the forum and by direct email I've priced up a small batch of antennas made to the same specification as the one shown in the photographs.

For customers in the UK and Europe the price is £130.00 including shipping plus VAT making a total of £158.00. For international customers including the United States the price including shipping is $200.00.

I'll prepare a web page with more information and PayPal buttons tomorrow. I'll post a link to the new web page when it's ready.

Regards,

Chris


Greg_2e1gw
 

Wonder if I can fit one of those into my teeneaged daughter's room for her Medium Wave French and Spanish listening... Suspect much as she likes listening to that stuff I suspect that this might just be considered a step too far!
Cheers
Greg
M6ORT


David Cutter
 

A tuned multi-turn loop around the transistor radio usually works very well.

David G3UNA

 

From: CrossCountryWireless@groups.io [mailto:CrossCountryWireless@groups.io] On Behalf Of Greg_M6ORT
Sent: 28 September 2018 16:07
To: CrossCountryWireless@groups.io
Subject: Re: [CrossCountryWireless] One-off special...Indoor HF Active Loop antenna

 

Wonder if I can fit one of those into my teeneaged daughter's room for her Medium Wave French and Spanish listening... Suspect much as she likes listening to that stuff I suspect that this might just be considered a step too far!
Cheers
Greg
M6ORT