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Author Topic: FCC Invites Comments on Petition to Eliminate 15 dB Gain  (Read 40477 times)
KA4KOE
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« Reply #75 on: July 26, 2016, 09:28:44 AM »

"A 3kw amplifier would exacerbate that problem further more either maxing out a 240 line current limit or requiring installation of a 400+ volt 3 phase line into the shack to power a 75lb transformer. I think 1500 watts is perfect as it stands and the direction of going to very high gain amplification is a great move ultimately."

Not true. You can run a huge 5 KW amplifier/appliance on 240 volts, 1 phase. Do the math...

For comparison, a typical electric range is around 8 KW.

5000w / 240V = 20.8A

Using the NEC safety factor (assuming continuous duty), 20.8 x 1.25 = 26A, give or take.

Install a 30 ampere, 2 pole breaker in your panel. Your circuit, assuming a short run, will consist of 2 No. 10 and 1 No. 12 (G). A neutral is not required on the primary of the amp transformer.

The key here is diversity. I doubt a 3 KW appliance will overload your house service unless you plan to run all your big appliances simultaneously.


« Last Edit: July 26, 2016, 09:31:46 AM by KA4KOE » Logged
KOP
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Posts: 346




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« Reply #76 on: July 26, 2016, 09:33:20 AM »

I did not know that just in the learning of Morse code would equip every radio amateur with the magical ability to tune a tube based amplifier.

I disagree, back then test was harder and code meant you just could not sit down and take a multiple guess test that you can see questions before hand from a pool. You had to work at it with time on air and using equipment with it and gained experiance

Sorry, I am a "no code extra", it must make me dumb or something.

A no code CB/Extra is nearly as easy to get as a old CB ticket. Most would not be Extra's under old rules. Pretty soon there will be just one ticket that will be mail order with no "test" and CB will be officially reborn. I worked very hard to get my extra well over 20 years ago and it meant something when I got it. Today Extra means nothing really because it is so easy to get.

I'll not justify my Extra class license to you or anyone . I'll not support it with a GROL and code element nor parade my education in front of AF7XT or my "experiance" behind it .
I am appalled that an old school Extra would exhibit so little class in welcoming new amateurs to the hobby based on "I worked very hard to get my extra well over 20 years ago and it meant something when I got it " . Right now it means little or nothing if you don't teach what you learn , set an example , and...
§97.1   Basis and purpose.
(a) Recognition ...
I have no idea on your activities here so I can not and will not speak to it .
(b) Continuation ...
Hard to do if you insist on working in a vacuum .
(c) Encouragement ...
Failure in the extreme . Fortunately I need no encouragement from you or anyone . 
(d) Expansion ...
Hard to do if you consistently believe that all new amateurs are somewhat less compared to your experience . This is a welcome that I rarely experience locally or face to face .
(e) Continuation and extension of the amateur's unique ability to enhance international goodwill...
If you can not or refuse to enhance goodwill within amateur radio how can anyone expect you to do so internationally ?
§97.101 (a) Just , fail .

Last but not least , take another shot at AA4HA , Tisha Hayes , and see how many friends it gets you . One less I'm sure .

Yet another "no code CB/Extra".

AF7XT Dennis

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I considered a microwave oven magnetron and a 4' dish as a drone-killer. The ERP would be on the order of a hundred thousand watts or so. ~anon

November 28, 2018, 09:16:04 AM
W9IQ
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Posts: 3552




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« Reply #77 on: July 26, 2016, 09:42:25 AM »

Quote
Not true. You can run a huge 5 KW amplifier/appliance on 240 volts, 1 phase. Do the math...

For comparison, a typical electric range is around 8 KW.

5000w / 240V = 20.8A

Using the NEC safety factor (assuming continuous duty), 20.8 x 1.25 = 26A, give or take.

You neglected to account for the ~40% efficiency of the amp. So the amperage would be closer to 60 amps.

But then the FCC isn't considering a power limit increase.
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- Glenn W9IQ

I never make a mistake. I thought I did once but I was wrong.
KM4AH
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Posts: 963




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« Reply #78 on: July 26, 2016, 09:43:07 AM »

 I enjoy talking to the new hams. But, if the code was still in place most of them would have never been general class. There is no way to cram for it, you have to do the work. As far as technical capability, a lot of the no code hams are better technicians than a lot of the 20WPM extras. It is ironic I suppose when a 20 WPM extra gets a CB'er to fix his amp for him.
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W8JX
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Posts: 13268




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« Reply #79 on: July 26, 2016, 09:53:49 AM »


I am appalled that an old school Extra would exhibit so little class in welcoming new amateurs to the hobby based on "I worked very hard to get my extra well over 20 years ago and it meant something when I got it " . Right now it means little or nothing if you don't teach what you learn , set an example , and...


I am not. A Extra was a goal to work for once upon a time and stood for something once. It is a give away now and more of a CB Extra class ticket than anything. I cannot change rules for sure but I do tire of those that defend a CB Extra being the equal accomplishment and bragging how they got their extra and earned it when they really do not have a clue what a Extra once stood for. Heck with today's rules I would not of gotten my Novice when I was 14 years old and worked my way thru General, Advanced and Extra over the years, I would of started as a Extra....

There was a time when most hams were technically inclined as it required a good grasp on thing to get a ticket including drawing schematics as mentioned earlier and calculating circuit component values for resonance but today it is nearly a mail order ticket and I have little doubt that one day it will become a test  free ticket and the modern day CB and the death of Ham radio...
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--------------------------------------
Ham since 1969....  Old School 20wpm REAL Extra Class..
KOP
Member

Posts: 346




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« Reply #80 on: July 26, 2016, 09:55:06 AM »

Back on topic ...
When a device as technically superior as the BLF188XR appears it would seem superfluous and a shame to have to add additional circuitry to limit gain and swamp the input when it can reach its full output with as little as 2.4 watts drive at 108mhz and possibly less at HF frequencies . Good IMD , surprisingly good linearity for a transistor of any kind (yes I know a MOSFET specifically LDMOS) welcome availability of good 50VDC supplies and excellent efficiency limited by a 15db gain rule is ludicrous in the extreme .

I'll build one long before this is settled in part 97 . Any objection from the usual sources about my 24db gain amplifier being illegal and not type accepted for use in amateur service ?

AF7XT Dennis    
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I considered a microwave oven magnetron and a 4' dish as a drone-killer. The ERP would be on the order of a hundred thousand watts or so. ~anon

November 28, 2018, 09:16:04 AM
AA4HA
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Posts: 2630




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« Reply #81 on: July 26, 2016, 11:05:54 AM »

You could run completely silly amounts of amplifier output, almost on continuous duty with even a tube based amp at modest efficiencies (let's say 65%). Most amateurs do not have antenna/ feedline systems that are really up to the task or receivers have have the selectivity and low noise floor to get close to reciprocity on an RF path (that is assuming that it is a symmetric propagation path, some aren't). It just makes them "alligators (all mouth, no ears).

It reminds me of the article that mentions "if I can hear em I can work em", that too is based upon a misconception about how radio propagation works and the assumption that the receiver conditions will be equal on both ends (they aren't, there can be a local noise source on one end or the other).

But back to the original discussion regarding a 15 dB gain limit on an amplifier; For example I have a PRC-174s greenie that has a (charitable) 20 watt transmitter output (or slightly more than 43 dB). If I had a 15 dB gain amplifier my power output (at the coax connector of the amp) would be 58 dB. This translates in to around 625 watts; quite the hefty output for a backpack radio on an amplifier. Of course this does not account for feedline losses, antenna (in)-efficiencies or whatever radiation pattern that antenna has to put power where it is more useful than just heating up clouds directly over your head.

How much more do you really need for gain? It is likely that the poor little transmitter is a bit of a splatter-box as it is.
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Ms. Tisha Hayes, AA4HA
Lookout Mountain, Alabama
KD8MJR
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« Reply #82 on: July 26, 2016, 01:18:08 PM »

Quote
Not true. You can run a huge 5 KW amplifier/appliance on 240 volts, 1 phase. Do the math...

For comparison, a typical electric range is around 8 KW.

5000w / 240V = 20.8A

Using the NEC safety factor (assuming continuous duty), 20.8 x 1.25 = 26A, give or take.

You neglected to account for the ~40% efficiency of the amp. So the amperage would be closer to 60 amps.

But then the FCC isn't considering a power limit increase.

You beat me to it  Grin

It is still possible but you better hope the AC, electric stove or the Hot water heater don't turn on at the same time your having your QSO Grin
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“A lie can travel half way around the world while the truth is putting on its shoes.”  (Mark Twain)
KM4AH
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Posts: 963




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« Reply #83 on: July 26, 2016, 02:00:49 PM »

I ran 5000 watts PEP output  consistently for years on 75 meters with a two tube Alpha 77SX and an out board 3 amp CCS Peter Dahl transformer and later with an 8K Henry.  Never had a minutes problem with either. Just a standard 200 amp residential service.

My back up heat strips in my heat pump air handler are 15 KW .

I have a 10KW electric resistance heater in my shop.

Not sure what some of you are thinking.
« Last Edit: July 26, 2016, 02:07:01 PM by KM4AH » Logged
KD8MJR
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Posts: 5557




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« Reply #84 on: July 26, 2016, 04:31:06 PM »

I guess it all depends on how your house is wired.  My main breaker is 100A which is pretty standard for most homes.  I know the bigger houses today use 200A breakers.  Also the outlets that are in a typical house for 220V are 30A.  The only exception are at the stoves and hot water heater which I think are 50A plugs.

73s
Rob


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“A lie can travel half way around the world while the truth is putting on its shoes.”  (Mark Twain)
KM4AH
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Posts: 963




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« Reply #85 on: July 26, 2016, 04:47:55 PM »

I guess it all depends on how your house is wired.  My main breaker is 100A which is pretty standard for most homes.  I know the bigger houses today use 200A breakers.  Also the outlets that are in a typical house for 220V are 30A.  The only exception are at the stoves and hot water heater which I think are 50A plugs.

73s
Rob





Yeah, my panel is 200 amp which is probably most common now although large houses can be 400 and more.

You can run a dedicated circuit for your amplifier, match the breaker, wire size, and outlet NEMA configuration for whatever you need.

In my case the main breaker panel is in the shack, so not much to it.
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K2GWK
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« Reply #86 on: July 26, 2016, 08:50:08 PM »


I am appalled that an old school Extra would exhibit so little class in welcoming new amateurs to the hobby based on "I worked very hard to get my extra well over 20 years ago and it meant something when I got it " . Right now it means little or nothing if you don't teach what you learn , set an example , and...


I am not. A Extra was a goal to work for once upon a time and stood for something once. It is a give away now and more of a CB Extra class ticket than anything. I cannot change rules for sure but I do tire of those that defend a CB Extra being the equal accomplishment and bragging how they got their extra and earned it when they really do not have a clue what a Extra once stood for. Heck with today's rules I would not of gotten my Novice when I was 14 years old and worked my way thru General, Advanced and Extra over the years, I would of started as a Extra....

There was a time when most hams were technically inclined as it required a good grasp on thing to get a ticket including drawing schematics as mentioned earlier and calculating circuit component values for resonance but today it is nearly a mail order ticket and I have little doubt that one day it will become a test  free ticket and the modern day CB and the death of Ham radio...

I am sick and tired of hearing that no code extras are not technical. I am a no code extra who got his EE degree back in 1976. I have designed low noise amplifiers, been a network analyzer and spectrum analyzer applications engineer and have sold RF and microwave test equipment for HP, Tektronix and Rohde & Schwarz. I have forgotten more than you will ever know. I wish you would just stop making these rediculous generalizations. You make yourself look like an ass.
« Last Edit: July 26, 2016, 09:01:57 PM by K2GWK » Logged

Guy
Lawn Guyland, New York

K2GWK Website
KM4AH
Member

Posts: 963




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« Reply #87 on: July 26, 2016, 10:01:04 PM »


I am appalled that an old school Extra would exhibit so little class in welcoming new amateurs to the hobby based on "I worked very hard to get my extra well over 20 years ago and it meant something when I got it " . Right now it means little or nothing if you don't teach what you learn , set an example , and...


I am not. A Extra was a goal to work for once upon a time and stood for something once. It is a give away now and more of a CB Extra class ticket than anything. I cannot change rules for sure but I do tire of those that defend a CB Extra being the equal accomplishment and bragging how they got their extra and earned it when they really do not have a clue what a Extra once stood for. Heck with today's rules I would not of gotten my Novice when I was 14 years old and worked my way thru General, Advanced and Extra over the years, I would of started as a Extra....

There was a time when most hams were technically inclined as it required a good grasp on thing to get a ticket including drawing schematics as mentioned earlier and calculating circuit component values for resonance but today it is nearly a mail order ticket and I have little doubt that one day it will become a test  free ticket and the modern day CB and the death of Ham radio...

I am sick and tired of hearing that no code extras are not technical. I am a no code extra who got his EE degree back in 1976. I have designed low noise amplifiers, been a network analyzer and spectrum analyzer applications engineer and have sold RF and microwave test equipment for HP, Tektronix and Rohde & Schwarz. I have forgotten more than you will ever know. I wish you would just stop making these rediculous generalizations. You make yourself look like an ass.

Good for you. But, if you had an EE in 1976 and ended up with a no code license one would suspect that you were unwilling to do the work to learn the code and waited until they dropped that requirement.
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KD8MJR
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« Reply #88 on: July 26, 2016, 10:50:01 PM »

Good for you. But, if you had an EE in 1976 and ended up with a no code license one would suspect that you were unwilling to do the work to learn the code and waited until they dropped that requirement.

If ham radio was what it was in 1976 then I would agree.  Sorry to say but the reality is that today ham radio is a fringe hobby that is typically not even recognized by most people and is definitely not considered cutting edge or high tech like it was in 1976.  Therefore the incentive to learn code is really really low for most new hams.  I can imagine in 1976 it was looked on in a much different light but times change.  The EE of today has to be able to do things that are way beyond what an EE from 1976 had to do and thats simply because the amount, variety and complexity of components has gone up 1000 fold.  I know, I am an EE also and while at the start I had only a theoretical understanding of HF circuitry because it was not something I ever needed to do in my job.  It did not take very long to figure it out and start repairing my own equipment and buying severally damaged radios and SS amps on the cheap on eBay and fixing them.  I won't touch stuff with tubes in them simply because my instinctive safety training in HV is not good enough for me to risk it. I admire the guys who are good at working with and fixing tube amplifiers. Even JX who is often one of my eHam nemesis.

CW is great but it is just another mode and not knowing it is no big deal.

73
Rob
« Last Edit: July 26, 2016, 10:52:05 PM by KD8MJR » Logged

“A lie can travel half way around the world while the truth is putting on its shoes.”  (Mark Twain)
K6JH
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Posts: 526




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« Reply #89 on: July 27, 2016, 01:03:43 AM »

Do 5 wpm Extras count, or are they the same as a no-code Extra?  Wink

I actually got a Novice in 1977, but got sucked into the vhf/220/uhf & repeater trap with a Technician license for many years. Got my General via the grandfather upgrade, and took the Advanced and Extra exams in one day. It didn't occur to me that I missed any questions - maybe because I'm also an EE since 1980. Working on medical products, doing ic design and wireless low power telemetry.

And back on topic: I think the FCC should eliminate the gain requirement. There are other ways to keep an amp from operating on 11m.

73
K6JH
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73
Jim K6JH
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