HELP WITH AMP GROUNDING.

[Stellasarat]

Since I've been back on the air after a 30 year absence my disablity has advanced some what. I want to use one of my tube amps but I only spend a few hours a week on the air. I know I will find it difficult to tune it and the wasted time warning it up is time wasted. I'd rather spend it on the air. While going through some boxes with a friend he pulled out a box marked 500 amp with power supply. Its a no name solid state with a 12v 35 amp p.s. hes no longer on the air but bid use it a while back with good reports. Just what I need. Turn it on and key it up. It has high med lo. So now it's mine. I have my radios on a hospital type table on wheels. It's a metal frame. When the mood strikes me to turn on a radio ill roll the table over my bed a turn something on. Can I ground it to the table? Or is that not such a good idea. I sleep in a hospital type bed all electric. It a made of a heavy aluminum. Can I run a wire with a alligator clip and when I want to get on the air clip it to the bed? I'm not looking to spontainiusly combust. I can run a long wire with a clip but where's the best place to clip (ground) it? Any advice would be of great help.

 

[W5LZ]

Just from the sound of what you've posted, I think I'd leave any electrical wiring to someone who knows what they are doing...
- 'Doc

 

[vkrules]

Do not ground that amp to your bed frame or mobile table, they are not earthed and could make things much worse.bad idea..

 

[M0GVZ]

Also you don't want to be within 30ft of the antenna running that power or you could suffer issues from RF exposure.

The metal bedframe and the table frame are not enough for a ground. You need a lot of it and it needs to be working from an outdoor antenna.

The higher the power the more work you have to put in. You will not benefit at all over 50W or so for local contacts. 500W is overkill.

 

[Stellasarat]

sorry bout dat.

Please ignore that post. On Thursday I had surgery. Thay gave me some loopy pills and holly, sxxt! I don't even remember writing that post. Now I understand why all these people have a pill problem. Back in the day thay would send you home with a three day supply of Percocet. These things are a totaly different monster. Bad stuff. I've two day's supply left. I guess ill just enjoy em. If you can't trust a guy who you allowed to cut you open then close you back up. Who can you trust. Is there any way to delete that posting?

 

[Road Squawker]

Also you don't want to be within 30ft of the antenna running that power or you could suffer issues from RF exposure....

not according to my MPE calculator

Amateur Radio RF Safety Calculator


--------------------------------------------------------------------------------

Calculation Results

Average Power at the Antenna 500 watts
Antenna Gain in dBi 2.2 dBi
Distance to the Area of Interest 30 feet (9.144 metres )
Frequency of Operation 27 MHz
Are Ground Reflections Calculated? Yes
Estimated RF Power Density 0.2022 mW/cm2


controlled Environment uncontrolled environment
Maximum Permissible Exposure (MPE)
1.2396 mW/cm2 0.2519 mW/cm2

Distance to Compliance From Centre of Antenna 30 feet (9.144 metres )

Does the Area of Interest Appear to be in Compliance? yes yes <More audio>


Interpretation of Results
The power value entered into these calculations should be the average power seen at the antenna and not Peak Envelope Power (PEP). You should also consider feedline loss in calculating your average power at the antenna.



Please also consult FCC OET Bulletin 65 Supplement B, the Amateur Radio supplement to FCC OET Bulletin 65. It contains a thorough discussion of the RF Safety regulations as they apply to amateur stations and contains numerous charts, tables, worksheets and other data to help determine station compliance.

 

[RatsoW8]

It take s a lot more power to risk rf exposure. I was within 30 feet on my yagi running 800 watts and the erp was much greater and the rf exposure was well within safe limits.

 

[Captain Kilowatt]

Length of exposure is involved as well. As an RF worker my limit of exposure was vastly greater than that of someone in a controlled or uncontrolled situation. We worked on live antennas with 1KW on the AM broadcast band. You quickly found out if your gloves had any holes in them however.

 

[Stellasarat]

asked the question under the influance

I've run an amp of varying wattage with every radio I've ever used. Granted I was a lot younger and know even less now than I did then ( memory loss ). All the amps had a three prong power cord. I'm sure thatll cover it. Even if the amp as the one I inquired about has the three pronger and the little bolt with a nut thats clearly printed ground. I've never grounded any amps or any of my radios. I've never in all those years had any problems that some may say you will have if you don't ground your equipment. The only difference is this is the first time I'm using a wire dipole as opposed to a traditional vertical ground plane antenna. I doubt that makes a difference. that's all I have to say about that.in about an hour I'm due to take on of those loopy pills. So if I write any crazy meaningless posts please forgive me. Ps as far as rf burns I much perffer George as I've never seen on of rf's tv shows. Is his wife also named gracey?

 

[space cowboy]

are you getting zapped from the equipment, bed, or cart? if not I wouldn't worry about it.

Length of exposure is involved as well. As an RF worker my limit of exposure was vastly greater than that of someone in a controlled or uncontrolled situation. We worked on live antennas with 1KW on the AM broadcast band. You quickly found out if your gloves had any holes in them however.

yowza. I touched the coil on a k40 putting out 30w once and ended up with a nasty burn, I don't even want to imagine KW.

 

[Captain Kilowatt]

yowza. I touched the coil on a k40 putting out 30w once and ended up with a nasty burn, I don't even want to imagine KW.

One kilowatt bites a little. 10 Kw hurts like old bejeebus and then some. Did that twice.....slow learner.

 

[222DBFL]

10kw can sure put the hurt on you, it can potentially kill you as well. I have been zapped once by my mic while running around 1500w, and it stings, let's just say that lol. Can't remember what caused it , want to say a loose connection or bad jumper coax.

 

[Captain Kilowatt]

10kw can sure put the hurt on you, it can potentially kill you as well. I have been zapped once by my mic while running around 1500w, and it stings, let's just say that lol. Can't remember what caused it , want to say a loose connection or bad jumper coax.

That was just from a little RF in the shack. 10 Kw is a little over 700 volts of RF across 50 ohms. I got zapped while working on a lighting choke that was isolating the AC power lines going to the tower lights from the RF on the tower. Turns out the choke was shorted making the "cold" end just as hot as the "hot" end. Getting zapped with RF is a lot different than getting hit with 60 Hz AC. It fries and burns. In my case it fried and burned at a rate of 960 KHz.

 

[Hurricane145]

All the amps had a three prong power cord. I'm sure thatll cover it. Even if the amp as the one I inquired about has the three pronger and the little bolt with a nut thats clearly printed ground. I've never grounded any amps or any of my radios. I've never in all those years had any problems that some may say you will have if you don't ground your equipment.

Same here. I did ground all the desk gear once and that is when I started having problems so it was short lived.
If you have older house wiring and only 2 prong outlets it would be worth having the shack rewired so you have a safety ground via the ground prong on the power cord.

Also, if you are using a ground rod for gear or antennas, you really must bond all ground rods to the service panel ground rod. Otherwise you have done yourself no favors.
RF grounds, Lightning grounds, and safety grounds are three different things.