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Author Topic: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx  (Read 10309 times)
KC4ZGP
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Posts: 1961




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« Reply #30 on: July 06, 2017, 10:52:21 AM »


Yup!

Ten-four.

Affirmative Charlie.
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VK3BL
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Posts: 1790


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« Reply #31 on: July 07, 2017, 02:51:30 AM »

Wow barely any worthwhile responses.  Shows how uninformed you all are.
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J.D. Mitchell BA  - VK3BL / XU7AGA - https://www.youtube.com/ratemyradio - Honesty & Integrity
KC4ZGP
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Posts: 1961




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« Reply #32 on: July 07, 2017, 10:56:53 AM »


You're right. There sure were a lot of weird responses even silly responses.

Good thing you don't mean me or JX.

Kraus

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VK3BL
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« Reply #33 on: July 07, 2017, 09:22:25 PM »

I asked a technical / design question and expected answers to questions like these:

1) Are single push pull amp designs better than multiple push pull combined amp designs
2) What are ARF1500 MOSFETs like compared to VRF/SD2933 MOSFETS?
3) What is the reputation for reliability of each amplifier?

Instead I got a whole bunch of crap about tube amplifiers, which is just ridiculous as anyone who frequents this forum knows I've done my time in that department.

I feel 'lets stick to the past' is such a stupid attitude for a hobby that was once on the cutting edge of RF development.  CBers currently do more work with SS amplifiers than Amateurs do.  And as for harmonics / dirty design, any off the shelf TVI filter will bring a 11/10M amp into compliance, as the 2nd, 4th, etc harmonics are beyond 52MHz...

So stop bitching about whether tubes or transistors are better, or whether increasing station automation detracts from operator skill.  There are plenty of other places to have those discussions.  But this thread posits a very specific question, and the vast majority of responses have been off topic and therefore useless in the context of the original question.
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J.D. Mitchell BA  - VK3BL / XU7AGA - https://www.youtube.com/ratemyradio - Honesty & Integrity
VR2AX
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Posts: 1016




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« Reply #34 on: July 08, 2017, 02:57:27 AM »

He's just winding you up just ignore it.

Sometimes the issue lies in the question. Classic answer to "Mr x you're not answering my question "... "Mr a you're not asking the right question ".

Fair result at Eden Park.
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KC4ZGP
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Posts: 1961




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« Reply #35 on: July 08, 2017, 07:35:49 AM »

Herr VK3BL,

You came here on your own, you expected, and are now disappointed. I cannot help you.

I still suggest build the EB-104 amplifier from Communications Concepts. It'll give you
something to do and give you a good feeling when it's all said, done and working.

You'll have to affix the heat sink, T/R relay, add a low pass filter and figure out the
power supply issue. I use two RS-35 in series with two RS-20s in parallel.

I get about four-hundred watts coupled with my Alico SR8T, D-104 and
delta loop antenna.

I finished the copper cubical cover for mine. I had to tame that RF.

You can fashion a power combiner and combine two EB-104s for 1,200 watts.

Is it in you to match the challenge.

This is a hobby.

73 to you and your family. Be safe. We need you.

Kraus

« Last Edit: July 08, 2017, 07:39:25 AM by KC4ZGP » Logged
VK3BL
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« Reply #36 on: July 08, 2017, 07:50:41 AM »

Herr VK3BL,

You came here on your own, you expected, and are now disappointed. I cannot help you.

I still suggest build the EB-104 amplifier from Communications Concepts. It'll give you
something to do and give you a good feeling when it's all said, done and working.

You'll have to affix the heat sink, T/R relay, add a low pass filter and figure out the
power supply issue. I use two RS-35 in series with two RS-20s in parallel.

I get about four-hundred watts coupled with my Alico SR8T, D-104 and
delta loop antenna.

I finished the copper cubical cover for mine. I had to tame that RF.

You can fashion a power combiner and combine two EB-104s for 1,200 watts.

Is it in you to match the challenge.

This is a hobby.

73 to you and your family. Be safe. We need you.

Kraus



Kraus,

The EB-104 sure is an interesting design, having read the white paper from Motorola.  Specifically, it is novel in that it doesn't use/need a combiner despite having 4 sets.

You'll certainly have fun if you go down the combiner route, and good on you.

My personal favourite challenge is QRO.  I've got a beautiful ex ups case sitting in the garage for just the right project.  I still can't decide whether to go something like a 3CX3000A7 or a bunch of the latest LDMOS super chips.

Previously in my mind the tube route was mandatory, given the extreme linearity advantage of the 3CX3000A7, but these days with pre-distortion it really doesn't matter.

The answer will come to me one day, but lets face it, high current 50v supplies are cheap as chips these days, where as decent EHT transformers are not.

Anyway, I was hoping to get more feedback regarding the design aspects of this particular amplifier.

A previous post suggested I asked the wrong question; I'm more of the opinion I asked the wrong audience.

73,

Jarrad
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J.D. Mitchell BA  - VK3BL / XU7AGA - https://www.youtube.com/ratemyradio - Honesty & Integrity
NO9E
Member

Posts: 888




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« Reply #37 on: July 08, 2017, 08:31:47 AM »

Quote
I asked a technical / design question and expected answers to questions like these:

1) Are single push pull amp designs better than multiple push pull combined amp designs
2) What are ARF1500 MOSFETs like compared to VRF/SD2933 MOSFETS?
3) What is the reputation for reliability of each amplifier?

Multiple push-pull amps require a combiner and are more complex. Single push-pull is better for reliability. At the time of THP, the only single push pull transistor that could deliver 1.5KW was ARF1500 operating at 125V. THP described the design in QEX. Lots so trouble getting a good match especially on 10m and not too good efficiency. No 6m.

Multiple push pull designs used established 600W modules and operated on 50V. No problem matching. New LDMOS can deliver legal limit with a single module at 50V. No problem with 6m or with efficiency.

I have Expert 2k-fa with 3 600W modules. One smoked and was replaced under warranty. Now the same company has a half-weight Expert 1.5k-fa with a single LDMOS module.

If any module in HL-2500 fails, instead of repairing it, it may be simpler to use  replacement LDMOS module. Same 50V.

THP had a very good reputation but their designs are dated. Also they required an external ATU; having internal ATU and an antenna switch greatly simplifies operations.

Ignacy, NO9E
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KC4ZGP
Member

Posts: 1961




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« Reply #38 on: July 08, 2017, 01:55:00 PM »


Jarrad,

I'm glad you have calmed down. Let's now talk EB-104.

Notice the drains and sources are connected directly to each other of either pair.
Then the pairs are connected push-pull.

The beauty of the FET is they can be paralleled without concern for drain-source
impedance problems. Like resistors, if you neeed more current with the same
voltage, just connect more resistors in parallel.

Same for the FET. However, gates must be kept apart as they are per the schematic.

My latest task is to add two FETs for six in all, three on each side. I have number five
and six added on the copper sheet heat spreader, their sources connected and their gates
biased at 3 volts d.c. I'm building up the courage to finally connect the drains and gates to
their outputs and inputs respectively.

I think my copper cubical is doing as it should. Folks actually come back with my call the
first time. So I take it RF from the antenna is blocked from re-entering the amplifier.

Duh! Kraus.

I will let you know how it goes. In the meantime begin your EB-104. You have your whole
life to complete it. You said the hobby is a lifetime thing not a 1-year thing.

73 and be safe. We need you.

Kraus
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KOP
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Posts: 346




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« Reply #39 on: July 10, 2017, 11:53:12 PM »


 This is just a hobby.


As I recall ham radio was based on experimental proper knowledge was required to use equipment that had different standards that for unskilled users like CB and business band. Today the standards for required knowledge and skill for ticket is a joke. The only thing that really separates today's ham radio is easy to past multiple guess test that question and answer pool that is widely available and pocket book. Soon even easy test will be gone too. Perhaps if many had had tickets for nearly 50 years like myself you would clearly see how the hobby has degraded to little more than a modern CB.  Lets hope that they do not make it as easy to become a police officer or a doctor with reduced standards.

https://www.eham.net/ehamforum/smf/index.php/topic,115523.msg1005849.html#msg1005849

The OP's question was ...

Just wondering peoples opinions.

The HL-2.5Kfx runs a pair of ARF1500s but is limited to 10M

The HL-2500Kfx runs 6x THP2933s but will do 6M

What are people's thoughts?



How in the world do you get to ...


snip~ Today the standards for required knowledge and skill for ticket is a joke. The only thing that really separates today's ham radio is easy to past multiple guess test that question and answer pool that is widely available and pocket book. Soon even easy test will be gone too. Perhaps if many had had tickets for nearly 50 years like myself you would clearly see how the hobby has degraded to little more than a modern CB.  ~snip

I swear John, I could start a topic about muffin mix and you would be on page three ranting about the state of Amateur Radio as you see it !

Give it a rest will you. If nothing else it is boring in the extreme.
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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
W8JX
Member

Posts: 13268




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« Reply #40 on: July 11, 2017, 11:05:31 AM »

Give it a rest will you. If nothing else it is boring in the extreme.

Never will. New extra class is a joke and a insult to those that actually earned it and I take offense to any suggestion otherwise. 
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--------------------------------------
Ham since 1969....  Old School 20wpm REAL Extra Class..
KC4ZGP
Member

Posts: 1961




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« Reply #41 on: July 11, 2017, 12:26:01 PM »


Hey JX,

I'm at a loss.

I'm on 17 meters phone at 2200UTC.

Won't you join me.

Kraus
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KD8MJR
Member

Posts: 5557




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« Reply #42 on: July 11, 2017, 01:15:42 PM »

Just wondering peoples opinions.

The HL-2.5Kfx runs a pair of ARF1500s but is limited to 10M

The HL-2500Kfx runs 6x THP2933s but will do 6M

What are people's thoughts?



A very close match but the edge goes to the 2.5Kfx.
I have both Amps and I guess if I was an avid 6M fan my opinion might differ but for 160-10M the 2.5Kfx is Superior in just about every way, mainly because it's built better in every way.   It uses a solid copper heatsink that weighs a ton and a huge transformer and caps for the 50Vdc.  The 2500fx uses an aluminum heat sink and dual switching power supplies that are just able to handle 1500W.
The 2.5Kfx will hit 2200W without skipping a beat, the 2500FX should never be run beyond 1500W or you risk burning out a power supply.  The real kicker is that the 2.5Kfx is actually a much smaller amp on the desk than the 2500FX.

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)
K7JQ
Member

Posts: 1316




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« Reply #43 on: July 11, 2017, 05:47:28 PM »

Just wondering peoples opinions.

The HL-2.5Kfx runs a pair of ARF1500s but is limited to 10M

The HL-2500Kfx runs 6x THP2933s but will do 6M

What are people's thoughts?



A very close match but the edge goes to the 2.5Kfx.
I have both Amps and I guess if I was an avid 6M fan my opinion might differ but for 160-10M the 2.5Kfx is Superior in just about every way, mainly because it's built better in every way.   It uses a solid copper heatsink that weighs a ton and a huge transformer and caps for the 50Vdc.  The 2500fx uses an aluminum heat sink and dual switching power supplies that are just able to handle 1500W.
The 2.5Kfx will hit 2200W without skipping a beat, the 2500FX should never be run beyond 1500W or you risk burning out a power supply.  The real kicker is that the 2.5Kfx is actually a much smaller amp on the desk than the 2500FX.

73s
Rob


Finally....a qualified response from an experienced THP user that has both amps.
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G3RZP
Member

Posts: 1321




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« Reply #44 on: July 11, 2017, 06:03:37 PM »

In post #4, K6AER said
Quote
I find it interesting that more and more hams cannot or will not own a price of equipment that requires more work than an On/Off switch.  Tuning a tube amplifier takes about 15 seconds. Once you  write the numbers down it takes 6 seconds.

I find it interesting that a large number of Extra Class calls appear totally unable to do this or actually understand what happens when they tune.

When I took the UK exam in 1963, you had to have at least some understanding of radio technology. It doesn't appear to be the same now, even in the UK requirements, let alone the US Extra Class (which is I believe, a broader spectrum than the UK).
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