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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Re: Looking for a UK ham who can support with Wellbrook loop enclosures
Hi, Jorge here (M0LDW...also LW5DX) in Leeds. I found them in different variants in Amazon UK. I don't think there will be an issue with the stock.
The way to search is looking for: "20mm Conduit 2 Way U Box" if galvanised metal, "2-Way Through Box, 20 mm Syste m, White", "2 Way Through Junction Box 20MM BLK, Conduit Fittings Bodies/Boxes Cable Management", or "PVC Conduit Circular Boxes Two-Way-Through- 20mm / 25mm".
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I hope it helps and keep me informed on the advances!
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73 DX DE Jorge, M0LDW in IO93FU
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Looking for a UK ham who can support with Wellbrook loop enclosures
Dear UK ham,
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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: LN 1530 Wellbrook amplifier replica deaf on LW - MW
Francesco, that label means the maximum RF and DC input both
ports can take before damage--it has nothing to do with the actual
S21 output level--you have to measure it as I showed in a recent
post along with a simple? test fixture to get an approximate level
of your specific VNA.
Steve
On 1/9/2025 12:22 AM, Francesco Caizzi
via groups.io wrote:
toggle quoted message
Show quoted text
Goodmorning, An answer to your appreciated questions...
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Thank you all again, Francesco Caizzi IU4TSV.
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Re: LN 1530 Wellbrook amplifier replica deaf on LW - MW
Goodmorning, An answer to your appreciated questions...
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Dave Martin - What can I say, I use these capacitors in all my electronic constructions... I can say that I can trust them...
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Thank you all again, Francesco Caizzi IU4TSV.
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Re: LN 1530 Wellbrook amplifier replica deaf on LW - MW
I agree that oscillation is possible, but it should be noted that the amplifier is push-pull, and the 1T coil driving the transistor needs to be in opposite phases.
You can view the schematic diagram here
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Re: OptiLOUPE for OptiVISOR
I have had an Optivisor and loupe for the past several years.. it has worked well! But.. now the lens in the front pops out now an again and the visor has black push buttons to hold it in.. if you have a loupe it is held in by a spring loaded screw. It always seemed to me the plastic head band could have been better as this was not inexpensive..
I am now looking at loupe glasses for my radio work. A desk microscope would be great but it takes up way too much space..
A variety of lenses are made which work well.. the higher the mag the closer the work.
Best
Guy N1GMM
--
73/
Guy, N1GMM
Web Presence:
Withywindle ( )
tom-bombadillo ( )
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Re: OptiLOUPE for OptiVISOR
I used a stereo microscope at work daily for the last 10 years of my electronics career. The B&L were most common, but I used my personal Zeiss scope. The B&L scopes were used with fiber optic halogen light sources that could brand your skin if you touched the bright end. My scope had a florescent ring light. In my opinion the ring light gave the most even lighting, but it had cool white color spectrum and that made reading resistor color codes a problem. I do not have any experience using LED ring lights made for video cameras but I expect they would be perfect for the purpose. ALL of the scopes had added 0.5x adapters added to the final lenses. That halves the total magnification but doubles the working distance under the scope. That is really a requirement. The adapter lens is also cheap protection for the expensive lens system of the microscope. You absolutely want to protect the expensive scope from deposits of crud from solder smoke and spitting flux or anything else coming off your work piece. All of the B&L scopes had 10x eyepieces. The 0.5x adapter made that 5x actual optical magnification. My scope had 15x eyepieces, but I used it at 0.5x zoom level. The added 0.5x adapter made that about 4x optical magnification. I preferred having slightly more field of view but could still zoom in if I needed more detail. In actual fact, many of the other techs used their florescent adjustable arm bench lamps with a 6" glass lens in the middle. With young eyes that gave enough magnification to do the work but I could always tell the difference when I compared their work against similar work done under a microscope.
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Those bench lamps had around 2x-3x magnification but had excellent eye relief and around 6" (15cm) working distance. It is critical to have enough working distance to get your soldering iron under the lens system. The more magnification, the less working distance. The 10x 4" adjustable arm desk lamps I see on Amazon claim to have useful working distance. When I tried a 3x headband, I was worried I'd burn my nose with the soldering iron.... I tried a 10x jeweler's eye loupe but that was useless except for doing close inspection. I haven't tried a video camera system but I look at them online. I've considered playing around with cheap USB computer cameras, USB inspection cameras, or fancier DLSR cameras with close-focus lenses. For a DIY system I'd recycle a gooseneck desk lamp as the camera mount and use a LED ring light with the camera. I've ordered a 10x 5"x3" magnifier adjustable lamp from Amazon to try. I ordered one with 19" arms so it can mount further back on the table.
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LN 1530 Wellbrook amplifier replica deaf on LW - MW
I have two handheld VNAs--a Seesii NanoVNA-H (3 inch screen) and a Zeenko LiteVNA 64 (4 inch screen). Using a SA with VNA set to Start 1 MHz and Stop 1 MHz, the VNA-H S11 output was about -10 dBm; the LiteVNA was about -5 dBm. Note both outputs are a square wave. I rigged up a very simple test fixture using a diode, filter cap and DMM set to volts and calibrated it from -10 dBm to +10 dBm. If you're not sure what your VNA's S11 output level you could measure it using this set up. I've made a file in Photos and put the file in it, labeled "VNA S11 Output Level and Test Setup and Results". /g/loopantennas/album?id=29989573, Steve AA7U
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Re: LN 1530 Wellbrook amplifier replica deaf on LW - MW
What I mean is that the input coupling capacitor may not be the value it's marked with.? In 40 years of repairing electronic equipment I've run into many cases of mismarked, or maybe just floor sweepings parts.? We had a package of .1 uf bypass caps that all measured about 15pf and a bunch of 2N3055 transistors that were PNP not NPN and the best ones were 1% resistors that measured not closer than about 20%.? My "guess" is just that like all the other guesses you have received.? I've found it pays to not overthink the problem until you have checked the simple things first.? I've been guilty of not checking the power supply first, many times, when I was in a hurry.? 73? Dave
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Re: LN 1530 Wellbrook amplifier replica deaf on LW - MW
The saturated output power of meany of the decent loop amplifiers is >+20dBm, which can easily damage a Spectrum Analyser input.
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I was always taught to put an external 20dB attenuator on the input to the SA, as a sacrificial item, in case you accidentally squirt too much RF or DC into it. This was back in the day, when SA's could easily cost >$50,000. But even with a $150 item, I still think it's worth doing, as you hardly ever need to use the SA full input sensitivity, and you nearly always remember to take more care if you have removed the attenuator for some reason.
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Regards,
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Martin
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Re: LN 1530 Wellbrook amplifier replica deaf on LW - MW
Whenever I check presmps for whatever purpose, I always assure the input level to the presmp is around -45 dBm.? I use the Rigol SA equipmed with the tracking generator.? The generator is set to -20 dBm (the minimum).? I add another 25 dB attenuator to that for a total of -45 dBm.?
Dave - W?LEV
On Sat, Jan 4, 2025 at 7:21?PM Steve Ratzlaff via <ratzlaffsteve= [email protected]> wrote:
Yes, Tom is correct-- it's entirely possible a second attenuator
is needed on the VNA's receiver S21 port to prevent overloading
the VNA. The specs of the VNA should state the max S21 input.
The other consideration is not overloading the preamp DUT--input
impedance S11 and gain S21 will not be correct if the DUT is
overloaded. I like to ensure the DUT test output is not much over
0 dBm--a decent preamp should not be overloading at that level.
The ALA1530LN has about +22 dB peak gain--so for 0 dBm output that
would be -22 dBm input. Most of the inexpensive nanoVNAs have a
fixed transmit S11 output, usually in the +10 dBm to -10 dBm
range--the VNA specs should tell what that level is. Knowing that
along with the DUT gain, you can get an estimate of the input
attenuator required.
73,
Steve AA7U
On 1/4/2025 5:10 AM, Tom ANderson via
wrote:
?Francesco,
I
want to say I might be wrong here so, please double check
me.
In
your drawing you show the 20db attn connected to the input
of the amp I assume this is to prevent over driving your
amp.? However, you do not have an attn on the output side.
Is
this accurate? ?
I
have read that you will damage your VNA if you apply too
much of an input. S21 port, So in my mind, you should have
an attn on both the input and output to protect the VNA?? If
this is not necessary please let me know.
Good
luck in your efforts?
?
Tom
Anderson
SDR_Radio@...
On Jan 4, 2025, at 6:03?AM, Francesco
Caizzi via <netsmo62@...>
wrote:
Francesco
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Re: LN 1530 Wellbrook amplifier replica deaf on LW - MW
Yes, Tom is correct-- it's entirely possible a second attenuator
is needed on the VNA's receiver S21 port to prevent overloading
the VNA. The specs of the VNA should state the max S21 input.
The other consideration is not overloading the preamp DUT--input
impedance S11 and gain S21 will not be correct if the DUT is
overloaded. I like to ensure the DUT test output is not much over
0 dBm--a decent preamp should not be overloading at that level.
The ALA1530LN has about +22 dB peak gain--so for 0 dBm output that
would be -22 dBm input. Most of the inexpensive nanoVNAs have a
fixed transmit S11 output, usually in the +10 dBm to -10 dBm
range--the VNA specs should tell what that level is. Knowing that
along with the DUT gain, you can get an estimate of the input
attenuator required.
73,
Steve AA7U
On 1/4/2025 5:10 AM, Tom ANderson via
groups.io wrote:
toggle quoted message
Show quoted text
?Francesco,
I
want to say I might be wrong here so, please double check
me.
In
your drawing you show the 20db attn connected to the input
of the amp I assume this is to prevent over driving your
amp. ?However, you do not have an attn on the output side.
Is
this accurate? ?
I
have read that you will damage your VNA if you apply too
much of an input. S21 port, So in my mind, you should have
an attn on both the input and output to protect the VNA? ?If
this is not necessary please let me know.
Good
luck in your efforts?
?
Tom
Anderson
SDR_Radio@...
On Jan 4, 2025, at 6:03?AM, Francesco
Caizzi via groups.io <netsmo62@...>
wrote:
Francesco
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Re: OptiLOUPE for OptiVISOR
I don't have a microscope, but it would be very useful to have. I have various magnifiers I use on occasion, but a microscope would be much better.
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===================================================================
Mike M
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Re: OptiLOUPE for OptiVISOR
I use a cheap Chinese copy using plastic lenses, that originally cost around ?8 GBP.
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It has a second drop down lens behind the first, to further increase the magnification, plus a single swivel monocular.
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It also had a pair of incandescent bulbs, either side of the headband, which I have swapped out for LED's powered by rechargeable cells, recovered from discarded disposable vapes, I often find littering the street.
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It works well enough for my purposes, as I still have to wear my prescription spectacles underneath, because they have corrective prism lenses.
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I also just acquired from AliExpress, a cheap <?20 GBP video microscope, with a desk mounted angle poise stand. This works really well when used close up, and can be connected to a PC for a larger display, or for taking videos and snapshots of items being viewed. The contrast isn't quite as good when the object being viewed is a few inches away, such as when soldering a PCB, but it's generally OK. The anglepoise stand is a great addition, as I can quickly swing the whole thing out of the way, when I don't need it.
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Here are some are typical listings.
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Updated version of my headband magnifier
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Some other styles
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4.3" digital microscope
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Anglepoise Stand
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All of these types of aids can be of considerable use, especially as we age. I tend to use SMD components most of the time, even when breadboarding circuits using "dead bug" or "Manhattan" style construction, and I don't really find it any more difficult than using much larger through hole components.
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Regards,
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Martin
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On Fri, Jan 3, 2025 at 09:46 PM, Mike M wrote:
The OptiVISOR is one solution:
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Re: LN 1530 Wellbrook amplifier replica deaf on LW - MW
?Francesco,
I want to say I might be wrong here so, please double check me.
In your drawing you show the 20db attn connected to the input of the amp
I assume this is to prevent over driving your amp. ?However, you do not have an attn on the output side.
Is this accurate? ?
I have read that you will damage your VNA if you apply to much of an input.
S21 port, So in my mind, you should have an attn on both the input and output to protect the VNA? ?If this is not necessary please let me know.
Good luck in your efforts?
?
Tom Anderson
SDR_Radio@...
toggle quoted message
Show quoted text
On Jan 4, 2025, at 6:03?AM, Francesco Caizzi via groups.io <netsmo62@...> wrote:
Francesco
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Re: LN 1530 Wellbrook amplifier replica deaf on LW - MW
Good morning, sorry if I didn't answer all the appreciated replies but yesterday I sat there to do some tests and I have to say that maybe the apparent poor sensitivity on the low ranges of the LN amplifier can also be attributed to the positioning of the loop? In fact I moved the test loop (1 mt) inside the laboratory connected to the T-Bias with another shorter test cable (even if the longer external cable is fine) and things seem to be going better. It is true that maybe positioning the loop on a branch of a tree (about two meters high) with a metal net less than three meters away plus one of those mobile shelters for cars probably also made of metal structure, with a sheet metal shed on the side also less than three meters away... maybe it's not the best condition for this reception band, while on others with other types of propagation it goes decidedly better. I tried with the sample made both with the two types of jfet (2SK932 and original 2SK715) and with the normal two transistors amplifier with the BFU590 (qx) and the results are more or less similar, so... I don't think there are problems of construction or electronic components. Having said that, I answer individually to those who answered me:
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Dave Martin: What do you mean? The coupling capacitors are those in the diagram, already used similarly in other amplifiers.
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Tom VE3PSZ: Ferrite material is always 73. BN 73-302 ferrite core.
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Steve Ratzlaff: Yes, I have had a NanoVNA from some time and in fact I really needed to understand how to do some bench tests of the amplifiers with that instrument. I made a diagram that I put together with the photos of the two boards, to understand if I understood well how to make the connections you suggested, if you can take a look at it... /g/loopantennas/photo/299839/3872714?p=Created%2C%2C%2C20%2C2%2C0%2C0
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Martin Southwest UK: Windings are correct, I have always taken into account the construction diagrams that appeared on the Wellgood Loop page which are always valid. However, for the test I tried to invert or rather "rectify" the connection of the secondary of the first transformer and obviously the amplifier DOES NOT WORK AT ALL...
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Everett N4CY: In the meantime, thanks for the private replies, that's why I asked you if you sell an unpopulated board of your version to see what differences there may be... mine is already double-sided, since SMD elements need to be mounted. I also did some tests with the insulation of the copper wires from the ferrite body using 3D printed insulators and although I can confirm that the 73 material conducts (we are about 25-30 Kohm) at least audibly I don't see/hear differences, which surely there will be instrumentally...
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On the side of the discussion, yesterday I also tried to build the "Everett N4CY" version of the LZ1AQ amplifier using 4 BFU590GX transistors (the ones in the bigger case) and I have to say that the first tests are really impressive, at least inside my lab it receives better than the LNs and even better than the original LZ1AQ that I also placed outside hanging from a tree and powered via CAT7 network cable!! I was really amazed...ok thanks to everyone, Francesco Caizzi IU4TSV
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Not affiliated with them but have used them ever since I was trying to solder and wondered why I couldn't focus close enough.
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As you age you inevitably run into the issue. The OptiVISOR is one solution:
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I am posting this because I just got the OptiLOUPE accessory and it works really well. I could read the markings on a SOD-123 diode:
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As I understand it the OptiVISOR has glass lenses and the OptiVISOR LX has plastic lenses. The plastic lenses may not be as good, so bear that in mind if you are looking.
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I have the DA-4 lenses for the OptiVISOR and they work well for soldering surface mount components. I have the DA-5 lenses on the way. Thought I would see how they compare to the DA-4.
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===================================================================
Mike M
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Nick B.
Matt M0LMK - KI5GXV
Jorge Jaroslavsky
Guy Mengel N1GMM