loopantennas@groups.io

Either or both ways.

Grady

Re: Loop Antenna Prices

#15846

Yes, I do get it.? But the DIY option is always less expensive.? I am fortunate in that I've been home brewing since my early SWL days at age 8 and upward.? All my test equipment is HP or Agilent.? I have one Rigol spectrum analyzer, but the rest is professional equipment.? It's no low-end error-prone equipment (MFJ "antenna analyzers" come to mind) that graces most ham shacks, if they even have measuring equipment other than SWR? and use them with no real understanding of what's really going on.? STILL, the vast majority of hams judge the "goodness" of an antenna by the SWR they measure.? I always point out that a dummy load exhibits a really low SWR, but doesn't radiate too well.

Yes, I've worked in the design end of the commercial world of electronic "widgets" to well understand.? I really do.? But when I see something that I believe I "need" and the price is too high, the first thing I ask myself is how can I design and build it myself.? Or maybe first, do I really "need" it?? In evaluating my DIY common mode chokes above and beyond what the HP 8753C could tell me, I needed something to indicate the balance between the two conductors to my open wire feeders - basically the balance at the DM output of the chokes at power.? It didn't take long to cook a plan in the gray matter and visit the electronic parts stash in the cabinet and garage.

As far as transmitting loops are concerned, I went through the 2 kV rated variable capacitors pretty rapidly even at 100-watts.? Living at a mile high doesn't help.? I finally bought at a ham swap meet a 12 kV vacuum cap at max C of 1200 pF.? Won't quite make 160-meters, but close.? Need a shunt fixed cap that will take the voltage and current.?

Dave - W?LEV ?

?? ? ?

Show quoted text

On Mon, Jan 10, 2022 at 9:05 AM Tom Crosbie G6PZZ <tom@...> wrote:

You are still not getting it Dave, despite having business practices explained to you more than once. You have certainly not factored in your own costs in getting educated through to the point where you can build something acceptable to yourself. I doubt Mr Ikin and others are relying on cheap Chinese test gear either.

?

Let me give you another perspective. Not everyone has these skills. I had some skills but a disability leaves me unable to solder and to wield other tools with any degree of fitness, let alone safety. Therefore I have to buy certain items of equipment and pay what I need to, grateful that someone has designed, built and warranted it for me.

?

There are many sharks in our waters producing sub-standard products for the unwary. Please share with the group your test methodology and model numbers of test equipment. Show us your test results so we may compare your product with others available to us, better still, have one of your amps independently tested, then we, the buyers, can determine what we would buy or give a wide berth too. It is not for you to sit as judge and jury on the various products offered to us. The community decides that by choosing to buy. Bad products and manufacturers don’t last long in this hypercritical market place.

?

Tom G6PZZ

?

From: [email protected] <[email protected]> On Behalf Of W0LEV
Sent: 09 January 2022 21:10
To: [email protected]
Subject: Re: [loopantennas] GENERAL QUESTION

?

OK.? I get it.? But even if I include (my) labor at, say, $50/hour, add another $150. ? When we can buy highly capable vector network analyzers (NANOVNAs) and spectrum analyzers (TinySA) from China for less that $150 (that's top-end quote), there is no excuse for the high price of commercially available receive loops. ?

?

The point I would like to make here is that home brewing can save significant $$ and a lot is learned in the process.? And, I didn't copy anything offered online.? I used my noggin for the design and construction.? At 75 years old, it still works relatively well (but not as well as when I was 35!!!).

?

Dave - W?LEV?

?

?

?

On Sun, Jan 9, 2022 at 9:03 PM Tom Seeger <thomas.b.seeger@...> wrote:

You forgot to factor in the cost of labor to design the loop circuit, the PCB and the mechanical items. Then there is the labor cost to procure the parts. And finally the cost to build and test each one. Oh and the cost of returns, marketing, customer correspondences, quality control issues, packaging, book keeping etc.
Its one thing to take an existing design off the web and build something for your own use as a hobbyist. Its quite another thing when you try to run a business and make enough profit to feed your family. I'm not saying that super high prices are always justified, but I can understand why the prices are very much more simply the sum of the parts.
73 Tom

--

Dave - W?LEV

Just Let Darwin Work

?

--

Dave - W?LEV

Just Let Darwin Work

Re: Anyone perhaps able to ID this noise source on top band please?

#15845

I can not look at the link.? My PC cautions of a possible security risk.??

Dave - W?LEV

Show quoted text

On Mon, Jan 10, 2022 at 1:33 PM Chris Wilson <chris@...> wrote:

10 January 2022

Only daylight hours, AFAIK, and? MUCH louder on a big (about 380 feet in circumference) horizontal quad wire loop that along one leg runs parallel to overhead phone and mains LV power lines.

On my wide aperture Wellbrook loop about 70 yards away from the overhead lines and 20 yards away from the horizontal loop it's much reduced. The noise lasts 2 minutes or so mainly, disappears and comes back? few minutes later. (Usually, but fairly random other times). It's not emanating? from my house, it's there running batteries and all power off. If you can spare the time to look any ideas are much appreciated, it's a well defined pattern some may have come across before, thanks.

File names should be pretty self explanatory

--

Best regards,
?Chris? ? ? ? ? ? ? ? ? ? ? ? ? ? mailto:chris@...

--

Dave - W?LEV

Just Let Darwin Work

Re: Anyone perhaps able to ID this noise source on top band please?

Tomasz Lemiech

#15844

On Mon, Jan 10, 2022 at 2:47 PM Martin via <martin_ehrenfried=[email protected]> wrote:

Hi Chris,

It's typical of a switched mode power supply, which looks to have an approximate 9KHz component.

Power supplies stop abruptly when the power is switched off. This thing clearly has a spin-up and spin-down phase, both 3-4 seconds long.

It might be a large variable-speed motor. An elevator in my house draws similar patterns (it has a soft-start and soft-stop phase in order not to shake the passengers too much).

Regards,

?

--

Tomasz Lemiech

Re: New Chameleon CHA RXL receive loop antenna

#15843

On Mon, Jan 10, 2022 at 11:20 AM, Zulu-Romeo wrote:

On Sun, Jan 9, 2022 at 08:06 PM, Tom Seeger wrote:

Hi Zulu-Romeo. I wonder if you have compared the eBay loop amplifier (M0AYF circuit) to any other loop amplifiers in an A/B test? I have, and found it to compare quite well above 2MHz. But on LF and especially on VLF the M0AYF did not perform nearly as well as my LZ1AQ, Wellgood or Blue Wave amplifiers. It did do much better than the MLA-30 on longwave though :-)
Tom
Hi Tom, I have not compared as I have no other loop amplifiers here besides the M0AYF. But from South-Central Oregon, I consistently receive VLF signals from WWVB, the Jim Creek WA naval station, and a couple of NDBs with a Signal-To-Noise ratio of 12 to 20+ db so I am pleased with it.

I can also receive several distant MW stations here during the day via ground wave with this loop which are nonexistent on any other antenna here.

BUT,

I am not 100% sure that my amplifier is a true M0AYF design. I bought it on eBay. From tracing the board, it looks like the M0AYF design with minor changes. But maybe it has something far different than the Chameleon knock-off.?

??

It also could be that my VLF results are good with this amp due to the loop itself - my loop is made from 108" of 75Ω RG-11/U single-braid direct-bury coax. Both ends of the solid inner conductor are connected to the amplifier inputs, and the ends of the outer conductor are connected together through a 100pf capacitor with one side grounded. Not sure what the impedance is though.....?

Re: New Chameleon CHA RXL receive loop antenna

#15842

On Sun, Jan 9, 2022 at 08:06 PM, Tom Seeger wrote:

Hi Zulu-Romeo. I wonder if you have compared the eBay loop amplifier (M0AYF circuit) to any other loop amplifiers in an A/B test? I have, and found it to compare quite well above 2MHz. But on LF and especially on VLF the M0AYF did not perform nearly as well as my LZ1AQ, Wellgood or Blue Wave amplifiers. It did do much better than the MLA-30 on longwave though :-)
Tom

Hi Tom, I have not compared as I have no other loop amplifiers here besides the M0AYF. But from South-Central Oregon, I consistently receive VLF signals from WWVB, the Jim Creek WA naval station, and a couple of NDBs with a Signal-To-Noise ratio of 12 to 20+ db so I am pleased with it.

I can also receive several distant MW stations here during the day via ground wave with this loop which are nonexistent on any other antenna here.

BUT,

I am not 100% sure that my amplifier is a true M0AYF design. I bought it on eBay. From tracing the board, it looks like the M0AYF design with minor changes. But maybe it has something far different than the Chameleon knock-off.?

??

Re: Transmit Loop?

#15841

Hi Grady

No..apart from the Italian silly  expensive ones, but even they are limited..ie no 160m

You want a good one?? Then build one.. 

Simon g0zen

Re: Best SDR Receivers

#15840

THANK you Martin and Danny G for your great suggestions about SDR

ANYBODY in this Group living near Santa Monica, Calif ???

Garey Wittich?? Santa Monica, Calif.

On Mon Jan 10 2022 03:58:01 GMT-0800 (PST), Martin via groups.io <martin_ehrenfried@...> wrote:

On Mon, Jan 10, 2022 at 01:00 AM, gareywittich2000 wrote:

Never used a SDR -? just learning about them, as I watch these discussions.? I understand seeing signals across a freq range all at one time ( spectrum of frequencies ), but what does a "water fall" show - how the signal levels change ????? Do SDR measure and display SNR -? which would be good in comparing different antennas ( assuming a constant signal level is being received ).

Hi Gary,

If you want to try for yourself take a look at the many KiWi web sdr's that are available free on-line.

Software such as SDR Sharp does give an indication of received Signal to Noise Ratio.

If you want to try playing with that software you can download it from

You don't need to own your own receiver as you can choose a 'source' as being Spyserver network, this will allow you to choose other peoples sdr's that they have made public from a list or map that can be brought up within the software.

Both of these methods will allow you to get a feel SDR's without having to spend any money.

Regards,

Martin

Re: Transmit Loop?

#15839

On Mon, Jan 10, 2022 at 04:40 PM, Chris Wilson wrote:

I have received some really strong signals on 160 meters from people using a small transmitting loop

Yeh,

Simon is one of those guy's :-)

Re: Transmit Loop?

#15838

Hello Grady,

 Monday, January 10, 2022

 I have received some really strong signals on 160 meters from people using a small transmitting loop. I would imagine they are tuning with a BIG vacuum capacitor and the tuning will be fickle, but fair play to them, they are banging a hell of a signal out from what's a tiny aerial on top band. I would imagine these are home made loops and have some mega voltages on them, let the cat beware ;)

Best regards,
 Chris      mailto:chris@...

GH> Are there any transmit rated loops out there that are worth their salt?

GH> Thanks
GH> Grady

Re: Transmit Loop?

#15837

And what frequencies and power rating ?

Re: Transmit Loop?

ED MONTAIGNE

#15836

To purchase or to make?

Mr Ed?

Show quoted text

On Mon, Jan 10, 2022, 10:52 AM Grady Hawkins <gradyhawk1952@...> wrote:

Are there any transmit rated loops out there that are worth their salt?

Thanks
Grady

Re: Loop Antenna Prices

ED MONTAIGNE

#15835

Dave, I am 79 and my wife is 77 and we are both Amateur Radio Operators and enjoy building antennas more than we do talking on HF. I have been building antennas since I was 14 and will never get over the joy of having it work. Sometimes they don't work the on the first try, but solving the problem and seeing it work is part of the fun and what a great learning experience. We look at an antenna we are using (that we built) and think, "What can? do to make it better".

We too would love to see simple diagram or specs on your loop.

73's and look out for Darwin ites.

Mr Ed?

Show quoted text

On Mon, Jan 10, 2022, 9:57 AM Steven Greenfield AE7HD via <alienrelics=[email protected]> wrote:

I'm reminded of when a friend and I were watching Norm Abrams build something absolutely beautiful like a trestle table with free lumber scavenged from a barn being torn down.

She turned to me and said "In his half-million dollar workshop".

In any case... enough people choose to buy. For some of us, building is more than half the fun. For others, it is DXLing that is more than half the fun.

--
Steve Greenfield AE7HD

Transmit Loop?

#15834

Are there any transmit rated loops out there that are worth their salt?

Thanks
Grady

Re: Loop Antenna Prices

#15833

I'm reminded of when a friend and I were watching Norm Abrams build something absolutely beautiful like a trestle table with free lumber scavenged from a barn being torn down.

She turned to me and said "In his half-million dollar workshop".

In any case... enough people choose to buy. For some of us, building is more than half the fun. For others, it is DXLing that is more than half the fun.

--
Steve Greenfield AE7HD

Re: Anyone perhaps able to ID this noise source on top band please?

#15832

Very similar to an issue I have here, does it sound like a whirring noise if you listen to it? Mine runs for perhaps 20 minutes then 'has a rest' and may restart after 10 minutes or often longer.
I identified mine by taking a walk around with a MW radio, turns out to be a faulty inverter in a water pumping station some 30 metres away. Despite positive identification (with the assistance of the Water board themselves) there is no intention of replacing offending item as 'no money in budget'.

Re: Anyone perhaps able to ID this noise source on top band please?

#15831

On Mon, Jan 10, 2022 at 01:33 PM, Chris Wilson wrote:

Only daylight hours

Ah just saw that part.

Is it on / off at the same time every day (on a time switch), or does it vary with the weather (Solar PV,? street lamps, heating system) ?

Re: Anyone perhaps able to ID this noise source on top band please?

#15830

Hi Chris,

It's typical of a switched mode power supply, which looks to have an approximate 9KHz component.

Maybe a car or mobility scooter charger or Solar PV invertor (if it doesn't go off at night it may be one with a power wall / battery bank), variable speed motor / fan drive, but to be honest it could be almost anything these days.

I'd build a small loop antenna and try to DF the source if possible.

Regards,

Martin

Anyone perhaps able to ID this noise source on top band please?

#15829

10 January 2022

Only daylight hours, AFAIK, and  MUCH louder on a big (about 380 feet in circumference) horizontal quad wire loop that along one leg runs parallel to overhead phone and mains LV power lines. 

On my wide aperture Wellbrook loop about 70 yards away from the overhead lines and 20 yards away from the horizontal loop it's much reduced. The noise lasts 2 minutes or so mainly, disappears and comes back  few minutes later. (Usually, but fairly random other times). It's not emanating  from my house, it's there running batteries and all power off. If you can spare the time to look any ideas are much appreciated, it's a well defined pattern some may have come across before, thanks. 

File names should be pretty self explanatory

-- 

Best regards,
 Chris                            mailto:chris@...

Re: Best SDR Receivers

#15828

On Mon, Jan 10, 2022 at 01:00 AM, gareywittich2000 wrote:

Never used a SDR -? just learning about them, as I watch these discussions.? I understand seeing signals across a freq range all at one time ( spectrum of frequencies ), but what does a "water fall" show - how the signal levels change ????? Do SDR measure and display SNR -? which would be good in comparing different antennas ( assuming a constant signal level is being received ).

Hi Gary,

If you want to try for yourself take a look at the many KiWi web sdr's that are available free on-line.

Software such as SDR Sharp does give an indication of received Signal to Noise Ratio.

If you want to try playing with that software you can download it from

You don't need to own your own receiver as you can choose a 'source' as being Spyserver network, this will allow you to choose other peoples sdr's that they have made public from a list or map that can be brought up within the software.

Both of these methods will allow you to get a feel SDR's without having to spend any money.

Regards,

Martin

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