how does RF feel/taste? how about rf injury?

[AF6LJ]

Speaking from experience they hurt like hell, they call it RF Burn because it burns and while with low energy, and not accompanied by DC voltage it takes a while for the result to appear.

Now if you want bleached and desiccated tissue that smokes, add a few hundred watts and a few hundred volts...
Been there..
Done that (not intentionally)
Had the scars for twenty five years before they faded away.
Oh I almost forgot.
That experience was entirely painless at the time and there was so much nerve damage that except for the occasional stabling pain it itched a lot.
 

[TheDane]

Back in the 90's I was on packet - 144.675 MHz, the 10W output from my radio ran into a BNC T-splitter (my antenna cable wasn't long enough, so I used the t-splitter as a pass through with another cable on it - and everything would fit into my desk setup neatly).

One day I had to move something around below my table, where the t-splitter was located. When I grabbed the connector to move it, my TNC-2c decided to send a packet - while my thumb was touching the BNC male end. My finger felt like a nail suddenly had been hammered into it. (I knew what had happened instantly, as I heard the relay click and knew it was on TX - into 50 ohm, but the cable was quite long, and RG-58 - so I wonder what impedance my finger had, and what was offloaded into the antenna)

After a day or so, I had a really sore and hurtful white spot in the center of a ring - naturally fitting the end size of the BNC connector. It took a looong time to heal, and i remember at one point being able to pull out a piece of white dead flesh at the center.


On a different note, I was repairing TV's at that time. One day the cable going into the high voltage transformer broke off the stud we used to insert into the transformer. (Easy insert/removal - as the standard connection is just a wire, not good for a module repair station)
The end was exposed, and naturally it broke off right when I touched it - leaving my right finger in such close proximity that I could see a blue glowing halo around my fingertip. 15625 Hz, 27kV (as I remember) feels not quite fun. I could move my arm away, and did so very fast. It didn't hurt as much, but it's surely something I wouldn't recommend. (It was pure AC, as the tube was disconnected - a huge nasty capacitor that zaps - and that hurts too, I know...)

Other things that hurts when fixing tv's and not being lucky touching insulated items 100% of the time:
Touching the 1200V vertical line deflection yoke circuit feels like it kind of snerrs, or saws - as it is a saw tooth signal (at 50 Hz here in Europe). It stuns your arm for a while (minutes), and the few times I was so unfortunate, I was sweating tons afterwards.
Touching the 300Vdc capacitor contracts muscles while the capacitor de-energizes. It is amazing how much muscles can contract, and the feeling when discharging makes you aware how your muscles react. I have never touched 300Vdc live, it was always off net - and I was stuck until the voltage was low enough to 'get away' -  it might have been a mind trick, and time seemed to go very slow for an instant. Anyways, it is not recommended - and I'm happy to report that it's been a long while since I last touched something I later would rather have not.

In any case - use your mind before you use your hand - something I have learned, and used since.
- also having one hand in your pocket (or elsewhere, not touching ground or other conductive materials) is a super good idea.

[bd139]

High voltage scares me!

 A friend had a very illegal CB PA. think it was 100W or so. We tried it on a Heath cantenna. All good. So I lean out the window to connect it to the mast and have my finger on the end and the bastard keyed the TX. I felt it, then it stopped hurting after about half a second. Shouted at him to pack it in. Climbed back in and there was a black spot on my finger. This turned into a pimple, burst and within 2 days my entire finger went purple. Cleared up in a couple of weeks. Never hurt past the first half a second.

Then about a year ago I sliced the finger open with a Stanley knife which suspiciously didn't hurt even slightly. Reckon I killed off all the pain receptors 25 years ago!

[CopperCone]

damn I think I might get some protective gear from hollandsheilding!

[vk6zgo]

High voltage scares me!

 A friend had a very illegal CB PA. think it was 100W or so. We tried it on a Heath cantenna. All good. So I lean out the window to connect it to the mast and have my finger on the end and the bastard keyed the TX. I felt it, then it stopped hurting after about half a second. Shouted at him to pack it in. Climbed back in and there was a black spot on my finger. This turned into a pimple, burst and within 2 days my entire finger went purple. Cleared up in a couple of weeks. Never hurt past the first half a second.

Then about a year ago I sliced the finger open with a Stanley knife which suspiciously didn't hurt even slightly. Reckon I killed off all the pain receptors 25 years ago!

Nope!
You just got older & tougher!

I've noticed the same thing, & although I've had a few RF burns over the years, the loss of "sookiness" also seems to apply to places where the was no such burn.

[bd139]

Interesting point. Shame the rest of me seems to start hurting as I get older

I actually got a minor "warning shot" off my own hooky PA with a diode probe as well when I was replacing something. Must have burned myself a hundred times on hot transistors though.

[CopperCone]

well, at least its difficult to poke yourself with an N connector.

I have been getting zaps because for some reason, when you measure the voltage difference between the GFIC ground and the Earth Ground on a regular outlet, there is a 60V potential (with high Z meter)...

Feels like tingling/burn when I hold two different equipment chassis.
Why do I have a non GFIC ground? Because some of my equipment trips them.

If I connect my hp 70000 SA to a UPS, then plug the UPS into one of the GFIC outlets, it trips.. but not the other ones. I put 5 outlets in the lab during remodeling/putting in new rockwool insulation in the walls, and they are connected to 3 separate circuit breakers, it looks like I need to have seperate breakers and GFCI for the HP70000/UPS then the rest of my equipment.... my home has a new grounding rod too so I don't know what the fuck... 

I am guessing there is ALOT of Y- filtering in the power strip, GFIC and the HP70000, so it trips the residential limit... the traveling wave tube amps seem to do the same thing, so I have a separate outlet and power strip for non GFIC compliant devices... but it burns... enough to lean on the fucking equipment and you get painful tingles. it's a complete mother fucker (but only if you touch a GFIC connected chassis and a non GFCI connected chassis.

I almost want tog et rid of the GFCIs but I don't really trust half the shit I get on ebay.


however, this situation is still alot better then some of the shit I had to deal with in my life (being soaked by a electrohydraulic device not connected to a GFIC, with exposed wiring on 2 phase (that itself runs a cooling system at 150VDC).. then having wiring explode 2 inches away from your finger. I kind of appreciate GFIC since that near miss. No isolation in that thing either. What a fucking death trap that was.

[WastelandTek]

2 phase

not trying to be pedantic, I used to say this also, but I think what you mean is "split phase" unless you were around some very specialized plant power system

[retrolefty]

Many old Ham operators from the vacuum tube era can tell you about RF 'mic burns' on their lips caused by stray RF feedback in the shack. This started in an era where most homes didn't even have a distributed ground running between outlets. One had to install ground rod(s) learn and apply SWR rules about matching tube output to matching networks to antenna bandwidth, all in the hope to prevent those painful lips burns when holding the metal stand mounted microphone. That tended to inhibit long rag-chewing QSOs.   

[CopperCone]

2 phase

not trying to be pedantic, I used to say this also, but I think what you mean is "split phase" unless you were around some very specialized plant power system

yea your right. It;s just difficult to anticipate the DC ground wire being hot with line voltage when the thing is fucking powered off. I did not want to disconnect it because of ESD damage potential, now I just use a grounding clip when I work on stuff so this never repeats itself. Fuck leaving stuff connected to mains. most places are not equipped for that kind of stuff though.... you need to typically build something... or I guess shove a banana plug into the outlet ground but thats dangerous itself. Need a conduit ground with a pip clamp.

[CopperCone]

Many old Ham operators from the vacuum tube era can tell you about RF 'mic burns' on their lips caused by stray RF feedback in the shack. This started in an era where most homes didn't even have a distributed ground running between outlets. One had to install ground rod(s) learn and apply SWR rules about matching tube output to matching networks to antenna bandwidth, all in the hope to prevent those painful lips burns when holding the metal stand mounted microphone. That tended to inhibit long rag-chewing QSOs.   

Are you saying that the metal bit on the microphone meant to hold the filter / foam in place turned into a stray antenna capable of emitting enough power to burn someones lips capacitively?

[retrolefty]

Many old Ham operators from the vacuum tube era can tell you about RF 'mic burns' on their lips caused by stray RF feedback in the shack. This started in an era where most homes didn't even have a distributed ground running between outlets. One had to install ground rod(s) learn and apply SWR rules about matching tube output to matching networks to antenna bandwidth, all in the hope to prevent those painful lips burns when holding the metal stand mounted microphone. That tended to inhibit long rag-chewing QSOs.   

Are you saying that the metal bit on the microphone meant to hold the filter / foam in place turned into a stray antenna capable of emitting enough power to burn someones lips capacitively?

 I'm sayin many an old Ham operator had experienced RF lip burns, why and how is probably
beyond my abilities to completely understand other then 'RF in the shack' was real and had
many causes and cures. Some mics of the era were all metal and wired to the common lead of the microphone element.

[T3sl4co1l]

Also, the fact that audio systems were largely tube, back then, meant little demodulation of stray RF and thus feedback within the transmitter itself (think acoustic mic-speaker feedback, but EM driven!).

In short, RF going up the antenna feedline is dumb: there is no such thing as a good antenna design which has unbalanced feedline current.  If the line is not grounded frequently and solidly, that current goes right up into the shack, and develops voltages on all the equipment.  (The purpose of a balanced antenna is to not have to worry about grounding the feedline at all, and to ensure a consistent radiation pattern regardless of feedline orientation, length and grounding.  Doesn't that sound like a good thing not to have to worry about?)  If that doesn't cause malfunction already (it's a testament to the PSRR and filtering of any unit, that can survive common mode currents capable of RF burns, without itself malfunctioning!), it can be big trouble for the operator, or other equipment (that isn't so robust).

Tim

[babysitter]

Had a mild 10W burn which i received (haha) during my early ham radio career.

I wonder why no one yet mentioned raytheons' pacifying ADS - microwaving pain right into he upper skin layers.

https://en.wikipedia.org/wiki/Active_Denial_System

[CopperCone]

I think that is typically considered terahertz/mm waves rather then microwaves.

Kind of think though, would be nice to have a MM wave detector without needing 10000$ of mixers.

I also read some stuff about MM waves possibly being carcinogenic (in a unique way, despite being nonionizing)

[WastelandTek]

carcinogenic

Not sure what the mechanism would be, but I will concede that we seem to have a really poor track record predicting the long term health effects of new technologies.

was just reading a history of Tektronix last night...

A separate division was formed, celled 'Panelcraft' to make our own photo etched front panels. They rented space in the Sellwood district of Southeast Portland. Larry Vollum, Howard's brother was in charge of this operation. A very tragic event took place at 'Panelcraft'. Larry was cleaning the sheet aluminum for the panels with Carbon Tetrachloride. At that time it was not known that this solvent was highly toxic. Larry worked for several hours, without gloves and breathing the fumes. He absorbed enough of the poison to cause kidney and liver failure. Though he was flown up to the nearest kidney machine, in Vancouver B.C., there was nothing they could do and he died.

[CopperCone]

http://www.osa.org/en-us/about_osa/newsroom/news_releases/2013/intense_terahertz_pulses_cause_dna_damage_but_also/

Seems to coincide with various things I read about involving light causing skin healing. Seems to be a mixed bag. Then again we can't even figure out if alcohol is good for you or not....

Very interesting since hot objects produce some THZ (i.e. the glowbar is a THZ standard source (though broadband, and weak).

Perhaps this is part of the reason why fireplaces/campfires are kind of therapeutic/healing, sometimes (so long you avoid smoke). I end up feeling pretty good after I have been warmed up by a (distant) hot source. Radiation heating defiantly has a different effect then convective heating on the body.

[james_s]

I'm not sure how you could taste RF but I'm not about to try.

I've gotten a minor RF burn on my finger once, I had a small Tesla coil running on the table about 2 feet from my body and I reached over to turn off the light. My finger brushed the grounded screw holding the cover plate on the light switch. It felt a bit like something hot and abrasive scraping my finger, later on it felt more like a minor burn. I'd hate to see what a more severe RF burn feels like.

[Teledog]

First RF "burn" was in class in the 80's.
Testing a CB radio..had the bare coax center conductor accidentally touching my arm (on a grounded steel table) & was stupid enough to key it.
Only a couple watts..no marks, but surely felt it!
Second was touching a big glass diode on a 35W VHF rig, diode "felt " cool,.. until I keyed it..OW!!! Instantaneous pain!
No marks on the fingertip, diode was ice cold after keying it..initially thought the diode was the problem, but it was obviously an IBM error (Idiot Behind Machine error)
Stupid tricks..do not attempt!