LW1DSE's home aerials (or antennas)

Here are my 4 aerials home made. Rigids are made with 10mm (3/8" inch) copper tubbing used frequently as gas conducts. This is a 1/4 wave with a 1/2 added, and a stub to proper phase of both.

This is a 2m slot squeleton antenna. I learn about it in an old spanish book about TV antennas, around 196x.

Those another is a 10m vertical using metal roof of home as ground plane, and a 10m horizontal folded dipole, the aluminum can is a 4:1 balum built using ferrite tubes from PC monitor cables.

Back to them, the stailess steel water tank reservoir.

Those antennas look very well made Osvaldo. I guess they would survive bad weather or storms very well.

Have you seen the higher gain versions of the skeleton slot antenna? I've seen ones where the builders have added reflectors to the antenna, and even added directors as well.

Skeleton slot Yagis (two horizontal Yagis fed with a single slot antenna), were very popular here in the UK a few years ago, possibly because they gave quite a good gain and did not require a complex phasing harness/power splitter. Sadly, my QTH is very poor for VHF or UHF, I am surrounded by hills so my range is limited to maybe a few miles at best.

Many years ago I converted a five element FM broadcast antenna (88MHz - 108MHz) up to the two meter band. I used to take it out to nearby hill tops and work portable from there, mainly SSB.

Wow, your 10m balun looks like a beast! Again, this looks very well made!

73, Mark...

It's an old IF can. Big atmosphere catastrophes are very rare, fortunately. I suffer severily warm wheather, I fell OK 20°C or lower.

All of them are more than 10 years old, as they are soldered using recycled tin/lead for plumber's use, and rosin rock, they haven't the aluminum disadvantage that, when oxidized, radiater harmonics or start behaving intermitent.

Also, all of them are DC short circuited, in order to keem them safe from static charging and eventual rig damage. The 2 and 10m verticals are DC isolated because of tuning capacitance of gamma match, by the same reazon.

Regarding multiple arrays, no, I never tryed them. I have little space at roof, it is about 40m² only.

I always use lead/tin solder as well. Over here in the UK the sale of lead/tin solder was stopped a few years ago. The 'hobby' electronics guys can only buy lead free solder (legally) now. Electronics companies that repair old equipment can still purchase lead/tin solder.

Fortunately, when I first heard about the government announcement to ban lead/tin solder I went online shopping and bought LOTS of lead/tin solder, more than enough to last me my entire lifetime!

I also have some rolls of lead/tin/silver solder. I used to work in a place that re-manufactured automotive engine management units, and they used lead/tin/silver solder because it resists corrosion. When they closed down the department they were throwing away lots of things, and so I asked them if I could have some of the solder containing silver. They said "Sure, take what you want", so I ended up with about six rolls of the stuff! I found it very good for solder joints that get exposed to water. It does not go 'dull' like lead/tin solder, but remains bright and shiny. I think it is supposed to be better for joints that get exposed to high temperatures too.

OK about your lack of roof space. I still think you have done well to squeeze all of those antennas in there!

73, Mark...

Lead less solder is very prone to fracture with time and temperature. In my last job untill 2020 when pandemic come on, I worked in a small family company repairing lots of industrial electronic equipment and stuff, from tiny 50W SMPS for led lighting to 600Amper frequency inverter for AC or servo motors.

Commonly, 90/95% of the failures were fatigated solder joints, both at through hole and SMD components (maily resistors), and failure on electrolytic caps. An insignificant resitor type 0805 located at the gate of a power IGBT, that starts be intermitent contact, causes the gate to become undrived/unbiased with catastofic consecuences for the IGBT itself and the load. I seriously think that is another face of the programmed obsolescence of goods.

I never used leadless solder, and I have a reservoir of lead/tin solder wire too, but here it still marketed normally. I unknown any prohibition for use, sale or manufacture it.

My work involves repairing industrial electronics too. I mainly repair things like DC inverters and three phase AC inverters, either 230VAC input or 415VAC input. Many of them are capable of 650A or more output at around 350-450VAC out, sometimes up to 7000Hz (for high frequency industrial drive motors).

I am very used to loud explosions in my work!

The other day one of my colleagues managed to burn out a 15,000W resistor he was using as a test load. He was puzzled about why the resistor failed, so I did a calculation and worked out the he had fed over 36,000W in to it! The resistor was over 60cm long and maybe 20cm in diameter, with a ceramic core wrapped with three metal strips. He said to me that "it glowed as bright as a light bulb" just before it burnt out!

73, Mark...

This is my home, wiewed from Google Go Satellite. You can see clearly the solar panels set, and my humble neighborhood.

Wow, 36KW blowing into smoke in front of your face!!!

My explosions usually were very much moderated, some MOSFET or IGBT. But several times involuntary wrong placed 'lytics. I must confess that I exploded several of them. Some of their capsules still are inserted in the ceiling.

Normally when the IGBT or thyristor output devices fail it is loud but not too much shrapnel. I've seen some of the capacitors (about 10cm diameter x 30cm in length), explode and have heard and felt the metal foil and insulating material fall down on the workshop area from about 20-25m away. It's like being in a war zone on bad days.

It sounds like we have worked in very similar jobs over the years. It's a wonder we have survived hi hi.

73, Mark...

Yes, 18 years repairing industrial stuff. In fact, such company started with the videogame business, those ARCADE big machines, but as they was becoming obsolete, the owned turned into the area of industrial goods. Hundredths of SMPS's from few watts to several KW (remember particularly those Siemens 24V 40A very difficult to repair, suddenly they detoned into smoke without no apparent reason), metal detectors, ultrasound cleaners, welding machines (arc, mig, tig) ultrasonic generators to detect improperly closed fizzy drink bottles, AC/DC thyristor controller for DC motors (mainly Siemens), AC/AC inverters for AC squirrel cage motors or servos, solar cell regulators/inverters, pirometers, process controllers, PLC's and a large et cetera.

Apart from the arcade machines and video games everything else is the same here. I also used to repair medical equipment for the ambulance service, and some time working in development designing and building test equipment for automotive electronics. A few years ago I was also repairing and updating amateur radio equipment. I have a few more turns on the coil than yourself possibly, I have been servicing and repairing items for around 40+ years now.

The Siemens power supply you mentioned reminds me of the Indramat ones. They are known as "Indra-bombs" by my colleagues as they have a habit of exploding when first powered up after repairs. We have a special, really long test lead so that they can be enabled from 4m away!

It's funny, no one bothers when things go bang in the workshop, we just generally mutter "Fixed!" under our breath and just carry on working hi hi.

73, Mark...

This thrash.They have a half bridge topology with 2 MOSFET paralleled in each leg. The current sense circuit is about 10 units 6.8R in parallel. When MOSFET blows, this resistors dissapear, and with them all low power circuitry.

I never could understand why not to use a current transformer IN DEVICES of such.

I recognise those Sitop PSU's. I don't work on them but some of the other guys do. I tend to get allocated 'weird' stuff from 30yrs ago or more, normally every part I need is obsolete and I have to find modern day equivalents. I think I have some photos on my work camera of some of the larger items, I'll have to dig them out. I also get allocated lots of stepper drives too. The problem there though is that they can often be rack mounted types and we have no connection information for them. So not only do we have to work out the issues with the unit we then have to reverse engineer the thing in order to make the connections to test it.

There are test rigs for much of the more common items like Siemens, Lenze, Indramat, ABB (normally it's comm's we struggle with on ABB drives), and so on.

73, Mark...

Ok guy. Thanks for your comments. Sorry for went off topic (ham radio and related stuff) but the conversation went this way.
I see little activity here. Is the forum recently dveloped? I pasted a link to it in my whatsapp state to try to capture some colleagues.

I used to be loggged in at several forums (UK vintage radio, DIYAudio, DIYTube Audio, etc) but some went to too sterile discussions about cable for speakers, "the sound of coupling capacitor" or stupidities like those, that tired and bored me.
The more interesting for me was UKVintage Repair, really interesting guys there, but because of (supposed) spam from some countries, Paul, the owner closed the access from Argentina.

Whishing the best from 2026 for you, family, friends and all guys here.

LW1DSE said:

Ok guy. Thanks for your comments. Sorry for went off topic (ham radio and related stuff) but the conversation went this way.
I see little activity here. Is the forum recently dveloped? I pasted a link to it in my whatsapp state to try to capture some colleagues.

I used to be loggged in at several forums (UK vintage radio, DIYAudio, DIYTube Audio, etc) but some went to too sterile discussions about cable for speakers, "the sound of coupling capacitor" or stupidities like those, that tired and bored me.
The more interesting for me was UKVintage Repair, really interesting guys there, but because of (supposed) spam from some countries, Paul, the owner closed the access from Argentina.

Whishing the best from 2026 for you, family, friends and all guys here.

Click to expand...

Happy new year to you as well Osvaldo!

No worries about going off topic, it is still electronics so it all counts.

Thanks for adding the link on Whatsapp, every link helps folks to find us.

73, Mark...

OK. The mods, owners and administrators on these and other forum I'd participated, usually get hungry when the thread goes too heavily off topic. So I was worried by these circumstance. Particularly those at DIYAudio. (And, betwwen us, I always suspected or feel some level discrimination coming from a non-native-english speaker.).

Here are some pic taken from the spanish book where I took conscience about the existence of the Skeleton and Slot antennas. I had seen few ARRL's hanbooks but I don't remember an article about it. Please, feel free to erase them if there may be some kind of legal issues regarding copyrights.

Note that my construction resembles the leftmost of the last page. I added a coax balun to load the antenna as symmetricaly as it made me possible.

I was wondering, the skeletal slot antenna is bi-directional? Did you want a bi-directional antenna? The reason I ask is that there is an old collinear design by Fred Judd G2BCX that uses two 5/8 elements mounted dipole fashion that is very simple to build and gives about 3.5dBd (5.65dBi) gain and is omnidirectional.

The article starts on page 24 of this PDF: https://www.worldradiohistory.com/UK/Practical-Wireless/90s/PW-1990-11.pdf

He also designed a number of other popular antennas, one of them was the "Slim Jim" which was a j-matched folded halfwave:

https://www.hamuniverse.com/g2bcxslimjimantenna.html

He designed another "folded collinear" as well, but there was a lot more metal required and it had less gain than the antenna in the first link above.

73, Mark...