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Author Topic: Why can't HF amps above the legal limit made in USA be sold legally in USA  (Read 31425 times)
W8JX
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Posts: 13268




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« Reply #135 on: December 09, 2016, 03:30:35 AM »

These are the ones I got new in a bag at a garage sale.

Click Here

Think you picked the wrong photo. Green triangle is isolated ground, green dot is hospital grade, isolated ground hospital grade will have green triangle and green dot.

Of course, double check me, I'm not batting too well in this thread. Smiley

It was only photo they had. Isolated ground merely means that unlike normal sockets that the ground is connected to metal mounting bracket too on isolated it is not but ground pin is still grounded to main panel ground. (mine are indeed green dot)
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Ham since 1969....  Old School 20wpm REAL Extra Class..
K6AER
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Posts: 5726




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« Reply #136 on: December 10, 2016, 07:36:03 AM »

When you go into the hardware store there are several grades of sockets. The standard 15 amp. socket which is really a 12 amp socket cost $.79. The industrial grade 20 amp socket will cost over $3.00.

For my shack I ran a 30 amp circuit for the radios and the amplifier with a small sub panel and 4 breakers and a master disconnect. It only cost $100 more than just using an outlet plug for the amplifier. Bad storm on the horizon and I disconnect the complete shack from the AC feed. Most lighting damage comes in from the AC feed looking for a good ground like your tower ground.
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AA4HA
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Posts: 2630




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« Reply #137 on: December 12, 2016, 08:34:38 AM »

Interesting thread; it went off in to the weeds on several tangents. Here is a bit of clarification.

While wattage is I*E=W (amps times volts equals watts) the losses in a system are caused by resistance and current (I^R). It is the very reason on why electric utilities step the transmission voltages up to ridiculous levels.

For the same amount of power, the higher the voltage, the lower the current. Since losses are due to current and the resistance of the conductor you can reduce your losses by significantly increasing the voltage.

A residential service that is 120 volts at 20 amps (2400 watts) may be on a 12 KV distribution circuit (not that uncommon from the substation to the pole mounted transformer in your back yard). At 12,000 volts the current is 200 milliamps (same 2400 watts). The resistive losses (that turns in to heating of the conductors and connectors) is radically less.

Ramp that way up; US transmission (long haul power) is between 169 and 768 KV.

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US residential service is often 120 VAC. Yes, the neutral is the return on the hot so there is current flow. A 120 VAC circuit is usually three-wire (hot, neutral and ground). You do not want current in the ground; that is what is sensed with a CT (current transformer) inside of a GFCI breaker to determine if the circuit should be tripped. The neutral leg should exactly equal the hot leg with no current (usually less then 2 mA) on the ground leg.

On a balanced service like 240 volts the power is on the two hot leg, ideally with nothing at all on the neutral. Homes that have 120/240 service are "complicated" because the load in your home is never balanced perfectly between the two different 120 VAC legs and there is neutral current (but no ground current). In a perfect world (like a water heater) where it is all balanced power there isn't any current on the neutral. For many amateur radio amplifiers the high voltage transformer is usually a 240 volt input so it will have no neutral current. Though quite often things like filament voltage and control voltage is derived from 1/2 of the 240 volt circuit and for those loads there does end up being neutral current for the entire amplifier.

-----------

I too went the route of hospital grade outlets in my home and a whole-house surge arrestor at the entrance panel; It was e-x-p-e-n-s-i-v-e. (look up Leviton 8380) but practically eliminated most of my problems with lightning damage to electronics. (my home takes a direct hit several times a year, what a rude way to be awakened at 3 am).  I still unplug things and have given up on the idea of owning a desktop PC or Ethernet routers. I noticed that the better grade outlets does make a slight difference on certain high current appliances.

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As far as amplifiers; in the infinite wisdom of the FCC they impose a limit on the gain of an amplifier. At least they migrated away from calculating power based upon the electrical wattage input to the power supply.

All of the arguments (excuses) of "I want a bigger amp because it will last longer" are just that, excuses, rationalizations and red herrings. It is like saying "I want a car that can do 160 miles/hour because I need the acceleration to merge on to interstate traffic (more BS).

Most of us on here are adults; you know what is legal under the terms of your license. We also know that humans are awful at following rules and laws, particularly when it is on something they probably will not get caught for.  If you had a 10 KW amp are you telling me you would never ever (cross your heart and hope to die?) exceed the legal limit?

We all know that you will, just don't lie to us about it. You are playing the same sort of B.S. games that our politicians pull on us every day. You come up with a lame excuse, toss it out and then we all pretend that your word is gold.
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Ms. Tisha Hayes, AA4HA
Lookout Mountain, Alabama
W8JX
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Posts: 13268




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« Reply #138 on: December 12, 2016, 09:30:12 AM »

A residential service that is 120 volts at 20 amps (2400 watts) may be on a 12 KV distribution circuit (not that uncommon from the substation to the pole mounted transformer in your back yard). At 12,000 volts the current is 200 milliamps (same 2400 watts). The resistive losses (that turns in to heating of the conductors and connectors) is radically less..

Everything here is around 6900 volts on pole not 12kv. They also install boost transformer every several miles or so to raise voltage back up as they reach into rural areas. As far as residential 120v service being 20 amps, it is in theory but houses seldom have real 20 amp sockets of good quality and the wall sockets tend to over heat with steady 10 amp or better loads. When GM first started selling Volts they used to default to 12 amp charge rate (1440 watts) from a 120v wall socket with included wall charger. After issues with complaints for melted plugs from low quality wall sockets they changed default to 8 amps with ability to use 12 amp with a manual override but it resets to 8 amp default each time you restart charge cycle. I installed a high quality 20 amp socket in garage where we plug our 120v charger in and it stays cool at 12 amps. I also use a 10 foot 14 gauge appliance extension that I had to cut socket end off of and replace it with a high quality socket so it too stayed cool. 
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Ham since 1969....  Old School 20wpm REAL Extra Class..
KM4AH
Member

Posts: 956




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« Reply #139 on: December 12, 2016, 09:56:15 AM »

A residential service that is 120 volts at 20 amps (2400 watts) may be on a 12 KV distribution circuit (not that uncommon from the substation to the pole mounted transformer in your back yard). At 12,000 volts the current is 200 milliamps (same 2400 watts). The resistive losses (that turns in to heating of the conductors and connectors) is radically less..

Everything here is around 6900 volts on pole not 12kv. They also install boost transformer every several miles or so to raise voltage back up as they reach into rural areas. As far as residential 120v service being 20 amps, it is in theory but houses seldom have real 20 amp sockets of good quality and the wall sockets tend to over heat with steady 10 amp or better loads. When GM first started selling Volts they used to default to 12 amp charge rate (1440 watts) from a 120v wall socket with included wall charger. After issues with complaints for melted plugs from low quality wall sockets they changed default to 8 amps with ability to use 12 amp with a manual override but it resets to 8 amp default each time you restart charge cycle. I installed a high quality 20 amp socket in garage where we plug our 120v charger in and it stays cool at 12 amps. I also use a 10 foot 14 gauge appliance extension that I had to cut socket end off of and replace it with a high quality socket so it too stayed cool. 


All depends on where you are at. They built a new substation up the road and went to 24,000 or thereabouts here a few years back. They built the new line over the old line, new poles and all, then switched the transformers and attached to the new lines. I still have several of the old poles.
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KD0REQ
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Posts: 2389




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« Reply #140 on: December 12, 2016, 10:54:41 AM »

builder-grade outlets (when I was a novice they were 29 cents at the hardware store) are not good for much.

nylon cased outlets are primarily for abuse.  a good spec-grade outlet with bakelite and good thick internal buss and prongs will do ya fine if you don't have severe service and liquid splashes.  I have had surplus hospital-grade outlets from a complete hospital rewire in the 80s, only thing wrong was being in place, even passed the pullout test.  they clean up nicer and held the plugs.  but so do 10-pack spec grade outlets, which is what I fully replaced every creepy backstab POStuff that the house was built with.

continuous loads on an outlet without gas-tight connections behind the wall and good tension will get ya every time.  just like the creepy molded-on plugs on space heaters, grab one and it's warmer than the heater.

as for linears that have a bigger footprint than a broadcast transmitter... well, pal, you're only fooling yourself.
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W8JX
Member

Posts: 13268




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« Reply #141 on: December 12, 2016, 11:19:21 AM »

just like the creepy molded-on plugs on space heaters, grab one and it's warmer than the heater.

If you look closely most heat plugs actually have a thin piece on metal/brass folded in half to make blades of plug. It you take a fine screw driver or blade you can slide it between folded pieces and expand blades a bit and get a much tighter connection with wall socket that runs cooler too. 
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Ham since 1969....  Old School 20wpm REAL Extra Class..
AC6CV
Member

Posts: 302




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« Reply #142 on: December 12, 2016, 06:47:22 PM »

I've been watching this thread for some time. Finally my question would be why would an honest person even ask such a question. Sorry, I just never thought about why or where I might buy something illegal. i.e I'm frustated. The people in power know I want to be illegal so they prevent me from breaking the law. JMHO.
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KM4AH
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Posts: 956




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« Reply #143 on: December 13, 2016, 05:03:36 AM »

A residential service that is 120 volts at 20 amps (2400 watts) may be on a 12 KV distribution circuit (not that uncommon from the substation to the pole mounted transformer in your back yard). At 12,000 volts the current is 200 milliamps (same 2400 watts). The resistive losses (that turns in to heating of the conductors and connectors) is radically less..

Everything here is around 6900 volts on pole not 12kv. They also install boost transformer every several miles or so to raise voltage back up as they reach into rural areas. As far as residential 120v service being 20 amps, it is in theory but houses seldom have real 20 amp sockets of good quality and the wall sockets tend to over heat with steady 10 amp or better loads. When GM first started selling Volts they used to default to 12 amp charge rate (1440 watts) from a 120v wall socket with included wall charger. After issues with complaints for melted plugs from low quality wall sockets they changed default to 8 amps with ability to use 12 amp with a manual override but it resets to 8 amp default each time you restart charge cycle. I installed a high quality 20 amp socket in garage where we plug our 120v charger in and it stays cool at 12 amps. I also use a 10 foot 14 gauge appliance extension that I had to cut socket end off of and replace it with a high quality socket so it too stayed cool. 


BTW, I had 125/250 here pretty consistently before they built the new substation. But, it wandered around with the time of day particularly in the middle of the summer and the middle of the winter. I suspect they were trying to keep the voltage within 5% on the far end of the line. Now, it is 120/240 on the money every time I have ever checked it.
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AA4HA
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Posts: 2630




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« Reply #144 on: December 13, 2016, 05:44:13 AM »

A residential service that is 120 volts at 20 amps (2400 watts) may be on a 12 KV distribution circuit (not that uncommon from the substation to the pole mounted transformer in your back yard). At 12,000 volts the current is 200 milliamps (same 2400 watts). The resistive losses (that turns in to heating of the conductors and connectors) is radically less..

Everything here is around 6900 volts on pole not 12kv. They also install boost transformer every several miles or so to raise voltage back up as they reach into rural areas. As far as residential 120v service being 20 amps, it is in theory but houses seldom have real 20 amp sockets of good quality and the wall sockets tend to over heat with steady 10 amp or better loads. When GM first started selling Volts they used to default to 12 amp charge rate (1440 watts) from a 120v wall socket with included wall charger. After issues with complaints for melted plugs from low quality wall sockets they changed default to 8 amps with ability to use 12 amp with a manual override but it resets to 8 amp default each time you restart charge cycle. I installed a high quality 20 amp socket in garage where we plug our 120v charger in and it stays cool at 12 amps. I also use a 10 foot 14 gauge appliance extension that I had to cut socket end off of and replace it with a high quality socket so it too stayed cool. 

----------------------
Great point regarding distribution voltages; I have seen some systems that are still as low as 2400 volts in to the neighborhoods. Most of those were on the east coast (north of Boston on the utilities I have directly worked with). When you see gigantic (insulated) conductors on utility poles you just know that their infrastructure is old-old-old.
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Ms. Tisha Hayes, AA4HA
Lookout Mountain, Alabama
W8JX
Member

Posts: 13268




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« Reply #145 on: December 13, 2016, 05:46:43 AM »

BTW, I had 125/250 here pretty consistently before they built the new substation. But, it wandered around with the time of day particularly in the middle of the summer and the middle of the winter. I suspect they were trying to keep the voltage within 5% on the far end of the line. Now, it is 120/240 on the money every time I have ever checked it.

I had 121/242 last time I checked but it has been a while. When I first bought this house over 30 years ago it was closer to 117/234.
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Ham since 1969....  Old School 20wpm REAL Extra Class..
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