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Author Topic: Cheap 10 meter amp  (Read 78770 times)
KA4WJA
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Posts: 1098




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« Reply #45 on: June 13, 2014, 04:49:36 AM »

Actually, in addition to the module part numbers or at least the number of the devices/transistors themselves, I assumed we were hoping he'd provide a schematic that HE drew of his amp?  (well, that was what I think would be the LEAST he'd need to do...)
They all have schematics, block diagram, service guides, etc. on line.  

What's the model number of the main unit (TV set itself) you're writing about?
That's the way I've built things....either cobble together something simple, and then draw it out....or most of the time, 'ya draw it out before 'ya pick up the iron...(at least that's the way I've done it for the past 40 years...but maybe I'm just a weird... Smiley)

While at first, I gave him the benefit of the doubt, it is apparent to me that this is all just BS.....whether he is "medicated", drunk, or mentally unbalanced, I don't know....but this IS all just BS...

73,

John,  KA4WJA
« Last Edit: June 13, 2014, 05:00:05 AM by KA4WJA » Logged
DL8OV
Member

Posts: 1057




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« Reply #46 on: June 13, 2014, 07:16:43 AM »

This afternoon I went on Google and searched for a 'Mitsubishi TV Scan Module'. There are many sites offering repair information on Mitsubishi flat screen TVs, a lot of information on Mitsubishi automobiles and one site that sells spares for Mitsubishi CRT televisions. After spending an hour on their site I could not see anything called a 'Scan Module' and the only heavy duty items I could find were switched mode power supplies.

One further point. The function of any line scan assembly in a TV set is to 1) drive the electron beam horizontally and 2) generate the high voltage for the CRT. Such a module would therefore only have two outputs and neither of these would be suitable for generating an RF signal as their normal frequency of operation is in the KHz range.

We therefore await more technical details from KA5PIU.



Peter DL8OV
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KA5PIU
Member

Posts: 446




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« Reply #47 on: June 13, 2014, 01:58:30 PM »

Hello.

First off, Yes, I was not able to find much of anything on this.
But, this was one of the very few CRT sets intended for HDTV.
It did have a digital tuner board.
So, I hooked it up to a function generator, and it did very well.
Was it designed for HF service? of course not!
But, ever look at earlier "Linear" amplifiers or the FT-101?
TV sweep tubes!
Yes, television sweep tubes!
Need I say more?
Anyhow, you will see that larger CRT TV sets used the same main board as the smaller sets, but added a much larger sweep section, and a power supply for the sweep section.
This is also done with "Premium" sound, an audio amplifier and extra speakers.
Things don't add up, well, get a life!
TV sweep sections are NOT intended for HF service?
Tell me something I don't already know!
The transistors on the board in question work in the HF region.
Again, you would have to be stupid not to figure out that this was not the intent of the design.
So, get off your ass, and see what else is out there that can do what it was never intended to do!

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KA5PIU
Member

Posts: 446




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« Reply #48 on: June 13, 2014, 05:50:26 PM »

Hello.

And, to make this clear, the meter I was using is a Dosy!
Just look up "Bird watts".
The Dosy is about 30% optimistic.
So, knowing that, I gave dissipated watts, and I would hope 100% efficient!
That is only the measure of power going in.
I do not have a bird slug for 500 watts, nor do I need one.
1000 watts is the maximum I shoot for.
You can figure volts and amps to figure watts in.
You can take a sampling dummy load, in this case 1%, input 500 watts and get 5 watts out.
And, remember a while back how the FCC ran around and fined dozens of truck stops?
Well, they lost in court!
http://www.texasstar.com/
http://www.copperelectronics.com/cart/
As shipped, all of the export 10 meter radios an "CW units" meet every FCC requirement.
You know all of the mods for the 2 meter rigs, clip the yellow wire or remove this one solder blob?
Well, same thing.
So, yes, a 10 meter amp can be legal, it is this "Peak and Tune" that is the problem.
Thank you.
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W9FIB
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Posts: 2529




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« Reply #49 on: June 13, 2014, 06:55:36 PM »

Like I said, this thread has been a complete waste of time. The last 2 ramblings prove it.
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73, Stan
Wisdom is knowledge you gain after you know it all.
W1BR
Member

Posts: 4195




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« Reply #50 on: June 13, 2014, 07:58:25 PM »

I feel like I am having a bad dream, and I can't wake up  Shocked
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N4TTS
Member

Posts: 253




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« Reply #51 on: June 13, 2014, 08:27:34 PM »

If you Google this guy, you'll see a pattern emerge on several internet forums where he comes in and blitzkriegs the group with the same type of drivel on whatever subject until the regulars catch on and call him out for BS.
It's the same MO.

Hello.

Blah, blah, blah.

Enjoy!

He's either mentally challenged or a troll.

Don N4TTS
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KA5PIU
Member

Posts: 446




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« Reply #52 on: June 14, 2014, 12:00:58 AM »

Hello.

We have gone from taking the sweep module out of a junk TV to insults?
Now, think about this.
TV sets of the Tube era were never designed to be transmitters, yet quite a few were converted for this, the sweep tube works well and the power supply provides the power.
So, I end up with the very same parts, but in solid state?
Lets leave it at that.

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KA5PIU
Member

Posts: 446




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« Reply #53 on: June 14, 2014, 03:33:12 AM »

Hello.

In addition to providing the HV needed for the CRT, it traces the electron beam across the screen.
True, it only operates at a few kHz, but the required bandwidth of the pulses are the problem.
Radar units send out pulses of usually under ONE kHz.
Look at the math, you need a few MHz of bandwidth.
Now, at look at this.
http://www.ittc.ku.edu/workshops/Summer2004Lectures/Radar_Pulse_Compression.pdf
That was what was intended by "Linear" it has to do with the bandwith.
Anyhow, study radars and how a signal of 600 Hz can occupy 1 MHz.
But, at SVGA, the bandwith required to faithfully reproduce the pulses is around 25 MHz.
http://www.pnto.ru/st/msman/V720_721_71.pdf
Again, there are plenty of radar tutorials that explain the concept.
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KA5PIU
Member

Posts: 446




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« Reply #54 on: June 15, 2014, 06:47:13 AM »

Hello.

And, to make this clear.
This would NOT meet part 97 criteria.
http://www.ecfr.gov/cgi-bin/text-idx?SID=cc6c64d9824378ecb9cea09194429620&tpl=/ecfrbrowse/Title47/47cfr97_main_02.tpl
It has WELL over 15 dB of gain.
And, exhibits this gain between 26 MHz and 28 MHz.
But, it does follow part 97.315 (1).
So, it is legal.
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KD8MJR
Member

Posts: 5557




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« Reply #55 on: June 15, 2014, 05:23:03 PM »

Threads like this should be deleted by the moderators.
The only thing this thread has going for it is a very catchy title that has drawn in a lot of people.
I see absolutely nothing of substance in it that contributes to the forum.
Logged

“A lie can travel half way around the world while the truth is putting on its shoes.”  (Mark Twain)
KA5PIU
Member

Posts: 446




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« Reply #56 on: June 15, 2014, 09:08:34 PM »

Threads like this should be deleted by the moderators.
The only thing this thread has going for it is a very catchy title that has drawn in a lot of people.
I see absolutely nothing of substance in it that contributes to the forum.


Hello.

The whole point of this is that there is a lot of discarded electronics that can be reused.
Have YOU looked at a discarded computer monitor?
OK, for every inch larger, you all but double the area of the screen.
Once you get to around 38", they weigh around 500 pounds!
Just look at the power supply of one!
With that said, I took a discarded unit apart, as I was thinking the ultimate Tesla coil power unit.
Normally they only can do perhaps 2 MHz on the transistors, house numbers of course, that is just the norm.
But, this was the exception.
Remember that this was a chance discovery, nothing was planned so not a lot of details.
Mitsubishi simply listed the "Deflection Unit".
I was interested in the killer audio section anyway.
So, all the parts got put in a box, and got involved in other things.
Some junked TV sound systems are impressive, some can do 500+ watts.
So, I put it all on hold for a few months.
I use a Tesla coil in a magic trick.
The time comes to see what the thing can do, what currents I can work with, how high a frequency I can work with.
Tesla coils normally only do a few kHz as well, but the higher, the better.
Remember that a Tesla coil is nothing but a CW transmitter.
With that said, look at what can be done.
At one time, Amateur Radio was about experimenting and exploring.
Now, it is all about whining, or so it would seem.
When was the last time YOU built a transmitter, not from a kit, but from a discarded TV?
At one time this was sort of common.
Remember that a Tesla coil is nothing more than a transmitter, in fact, a very simple one.
How impressive is your ham shack to the average person? yawn?, or WOW!
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KD8MJR
Member

Posts: 5557




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« Reply #57 on: June 16, 2014, 02:04:06 AM »

And this would all be so enlightening and believable if the story had one shred of proof to back it up! I am talking at the very least proof like some detailed pictures which by all accounts you could easily post on here .
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“A lie can travel half way around the world while the truth is putting on its shoes.”  (Mark Twain)
KA5PIU
Member

Posts: 446




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« Reply #58 on: June 16, 2014, 03:39:49 AM »

Hello.

What I did was take an old TV set apart, discover some interesting parts, and post my discoveries.
There was no intention but to get other hams interested in recycling junk appliances.
This was never intended as a "How to" but a what if.
My opinion is, if you can not understand the basic concept, I do not want to be the one giving you the reason for poking around inside a mains powered device.
This is not like pulling the covers of your talkie.
Others, who ARE aware of this type of thing, point out that this basic design is used on illegal CB, and this is true.
Now, here is the question.
You are telling me that some guy at a CB shop can make a go at this but a bunch of hams can not.
What exactly am I being told?
And, CB types call this the "Solid Rocket" (Solid State) or Tee Vee sand box, as the original design uses TV sweep tubes. or "Sweepstakes II", again, referring to the sweep circuit.
But, DANGER, no user serviceable parts inside.
Lets leave it at that.
CBers are smarter than hams.
Thank you.
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KM4AH
Member

Posts: 962




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« Reply #59 on: June 16, 2014, 03:40:48 AM »

I think it has been relatively entertaining myself. I have no idea what he is doing. Most of you don't either. And, he may not.
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