Re: loop material question
Thanks by the way. Forgot to add that in my reply ??♂??
John is my name.?
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Re: loop material question
currently using an mla30+, I am incapable of not tinkering.?
pre amped, probably will use LZA1Q but wouldn’t mind something stateside.?
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Possibly tuned with dual gang capacitor.?
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really my question is can I use sheet metal instead of tubing? I have a sheet metal shop and access to copper and or aluminum sheet and coil. If we are looking for the lowest inductance would for eg a 1m diameter loop made from 6” wide copper be acceptable??
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Re: loop material question
On Mon, Jan 13, 2025 at 12:47 PM, Simon wrote:
However, in general there is no such thing as too big a tube diameter.
Hi, Simon
A thicker tube diameter causes a higher loop capacitance and therefore has an impact on the self-resonance frequency of the loop.
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regards, Fred
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Re: loop material question
Hi
Welcome.
We need much more info on what you intend to make before advice can be reliably given.
Ie.. active pre amped no tune loop antenna,( ie lz1aq type,) high q tuned? Dia of loop, frequencies of interest etc etc.
However, in general there is no such thing as too big a tube diameter.( dia of tube not loop.) Its usually limited by what you have/ can get/ bend/ not worth the effort due to no real world gains, etc.
A name to call you?
Regards Simon g0zen
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Hello,
lots of great info here. I am new to the group IO format, just created an account. I have been paging through the topics and tags but I cannot seem to find anything that deals directly with the shape of the loop material. I have been debating building an upgraded receive only loop. I see most loops are made of round material, either tubing, wire, coax etc.. i am wondering if using sheet metal cut to a certain width then passed though a 3 pin roller to achieve the correct diameter would be OK? The 3 pin can also take up to 3/8" solid or hollow round stock. How wide would be too wide??
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Thanks a lot
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Re: Items that may be of interest to some
Le samedi 11 janvier 2025 à 11h06, Everett N4CY a écrit :
Happy New Year 2025 Everett
Thank you for your new document and for all your information and advice disclosed on this group
Best regards
Bernard
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Items that may be of interest to some
I have attached a link the has information on some of the items that I have designed that may be of interest to the group that will enhance your listening experience on the bands.
?
Everett N4CY?
?
?
https://www.icloud.com/iclouddrive/05098Uoz4s1Mo19gRTsehNv7g#Offerings_of_N4CY
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Re: AlexTune: max brightness != lowest SWR?
There could be many explanations for this, but I'll offer a few of the more likely ones.
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It may simply be that your loop is not a 50 ohm match, and when tuned for "maximum smoke", the actual input impedance is something other than 50 ohms.
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The Alextune is basically a simple RF "sniffer", and the nearby E-Field energises a LED, which glows more brightly as the RF field strength increases.
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I think the W2LI magnetic loop antenna is a slightly different design to the Alex loop, in that it uses two capacitors in what is often called a "Navy Match" and it doesn't use a separate feed loop.
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As a result, the RF field around the tuning box may not be entirely produced by radiation from the loop itself, and some of it may be from the internal wiring. Therefore, the localised E-Field, where the Alextune is attached, may not correspond to maximum radiation in the far field. I note that some versions of the W2LI magnetic loop also have an extra external balun box, which also suggests that here may be some unwanted feeder radiation too, which is not uncommon with many commercial loops. This will also distort the local E-Field around the antenna.
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If you are feeding the loop via a length of coax. The SWR you observe at the radio end, may not be the same as the SWR at the interface between the coax and the loop. If you tune the loop for best match at the radio end, it may well be something different at the loop, but as long as the radio is happy with the match, the SWR protection shouldn't kick in, and the radio should be producing it's maximum output power. However, modern transmitters don't have a 50 ohm output impedance, but they are designed to deliver as much power as possible to a 50 ohm load, as long as the output voltage and current don't exceed the rated limits of the PA devices. As a result, they can sometimes be "fooled" into producing more output into something that is not an exact 50 ohm resistive load, but one has some reactance present.
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I hope this helps.
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Martin
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Re: A link with will show items that might be of interest
Glads,
Thanks, now I will have to figure this out.?
On Saturday, January 11, 2025, 11:32 AM, Gedas via groups.io <w8bya@...> wrote:
you need to grant
access to everyone
Gedas, W8BYA EN70JT
Light travels faster than sound.....
This is why some people appear bright until you hear them speak.
On 1/11/2025 11:59 AM, Everett N4CY via
groups.io wrote:
I have attached a link the has
information on some of the items that I have designed that
may be of interest to the group that will enhance your
listening experience on the bands.
?
Everett N4CY
?
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Re: A link with will show items that might be of interest
you need to grant
access to everyone
Gedas, W8BYA EN70JT
Light travels faster than sound.....
This is why some people appear bright until you hear them speak.
On 1/11/2025 11:59 AM, Everett N4CY via
groups.io wrote:
toggle quoted message
Show quoted text
I have attached a link the has
information on some of the items that I have designed that
may be of interest to the group that will enhance your
listening experience on the bands.
?
Everett N4CY
?
|
A link with will show items that might be of interest
I have attached a link the has information on some of the items that I have designed that may be of interest to the group that will enhance your listening experience on the bands.
?
Everett N4CY
?
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Re: AlexTune: max brightness != lowest SWR?
Lowest (1:1)? SWR is the point where the highest level of power transfer occurs between the source and the load.
Not sure what an AlexTune is though
John?
On Sat, Jan 11, 2025 at 9:56?AM Todd - KE2AEQ via <ke2aeq+groups= [email protected]> wrote: Hello all,
?
I'm clipping an onto a W2LI magnetic loop antenna. I'm puzzled by something: the point at which it shines brightest is consistently about +20 kHz above what a NanoVNA (and the transceiver) indicates is the bottom of the SWR curve (on 40M).
?
What explains this? Is this a case where lowest SWR isn't necessarily where the maximum RF radiation is? Defective unit (would love to know what's inside)? User error?
?
Thank you!
?
-Todd
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Re: AlexTune: max brightness != lowest SWR?
Not sure but maybe the AlexTune is detuning the antenna slightly. Try running the NanoVNA with the AlexTune clipped on there and see if the Nano results are different.
Tony
AD0VC
toggle quoted message
Show quoted text
Hello all,
?
I'm clipping an onto a W2LI magnetic loop antenna. I'm puzzled by something: the point at which it shines brightest is consistently about +20 kHz
above what a NanoVNA (and the transceiver) indicates is the bottom of the SWR curve (on 40M).
?
What explains this? Is this a case where lowest SWR isn't necessarily where the maximum RF radiation is? Defective unit (would love to know what's inside)? User error?
?
Thank you!
?
-Todd
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Re: AlexTune: max brightness != lowest SWR?
The NanoVNA and your xcvr is telling you at what frequency the loop
is exhibiting nearest to 50 ohms resistive.
The AlexTune is showing the frequency of maximum power transfer,
indicating the the o/p impedance of the xcvr is not 50 ohms
resistive.
Mike - M0MLM
On 11/01/2025 13:51, Todd - KE2AEQ via
groups.io wrote:
toggle quoted message
Show quoted text
Hello all,
?
I'm clipping an
onto a W2LI magnetic loop antenna. I'm puzzled by something: the
point at which it shines brightest is consistently about +20 kHz
above what a NanoVNA (and the transceiver) indicates is
the bottom of the SWR curve (on 40M).
?
What explains this? Is this a case where lowest SWR isn't
necessarily where the maximum RF radiation is? Defective unit
(would love to know what's inside)? User error?
?
Thank you!
?
-Todd
|
AlexTune: max brightness != lowest SWR?
Hello all,
?
I'm clipping an onto a W2LI magnetic loop antenna. I'm puzzled by something: the point at which it shines brightest is consistently about +20 kHz above what a NanoVNA (and the transceiver) indicates is the bottom of the SWR curve (on 40M).
?
What explains this? Is this a case where lowest SWR isn't necessarily where the maximum RF radiation is? Defective unit (would love to know what's inside)? User error?
?
Thank you!
?
-Todd
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Re: Looking for a UK ham who can support with Wellbrook loop enclosures
Dear people,
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What a great quick support offers from you.
I have made a deal with Matt to help me getting those PVC boxes.
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Those, together with my own Alu bending machine and the N4CY PCB which fit perfectly in those boxes, will complete my home made loop :factory"...hi.
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I will post a picture as soon all is fixed.
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Thanks agn fr the great support!
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73e Michael
PA5M
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Re: Looking for a UK ham who can support with Wellbrook loop enclosures
? Hello Michael
?
? Yes they are still commonly used and a Google search on "20mm 2 Way Through Junction Box - White" brings up plenty of them, much cheaper than the one that you list.
? For example,
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? There is an extra 22p for the lid and the postage would however push the price up.
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? I could pick the following two items up locally and post them to you if you're happy to cover the cost and postage.
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? I wonder if you've tried your local electrical wholesalers as these are 20mm boxes and just as likely to be used in Europe as opposed to the UK?
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? 73s Tracey G5VU
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toggle quoted message
Show quoted text
----- Original Message -----
Sent: 09/01/2025 14:49:50
Subject: [loopantennas] Looking for a UK ham who can support with Wellbrook loop enclosures
Dear UK ham,
?
I am building my Wellbrook copy with the PCB from Everett.
This PCB fits into the original enclosure: 20mm 2 Way Through Junction Box - White.
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Unfortunately it is out of production with Schneider Electric as of Octiber 2024, but I found an online shop who showed they them in stock.
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I am not sure if those are still commonly used in the UK, but perhaps you can give me advice.
Tnx in advance!
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73e Michael
PA5M
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Re: Looking for a UK ham who can support with Wellbrook loop enclosures
Did anyone mention CPC? may also be available through Farnell their parent company.
?
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73
Nick
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Re: Looking for a UK ham who can support with Wellbrook loop enclosures
It seems that the exact Schneider part is also available from:
?
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and
?
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Feel free to email me directly (correct on qrz.com) if I can help.
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Matt
M0LMK
KI5GXV
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Re: Looking for a UK ham who can support with Wellbrook loop enclosures
I would be happy to post you some of these if you cover the cost.
?
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Matt
M0LMK
KI5GXV
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Superlite
Everett N4CY
Todd - KE2AEQ
Nick B.
Matt M0LMK - KI5GXV