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Author Topic: Metron 1000B on WARC bands?  (Read 2395 times)
KU7I
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Posts: 122




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« on: February 15, 2013, 07:08:05 PM »

Does anyone know if the Metron 1000B will work on 17 and 12 meters? Thanks
Lane
Ku7i
JH1JCM
US Naval Hospital Yokosuka
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AD4U
Member

Posts: 2150




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« Reply #1 on: February 16, 2013, 05:38:11 AM »

If this it the Metron solid state amp made in the 1970's I would be very careful about trying the WARC bands.  This amp was made before the WARC bands were available.  In this amp there are separate and specific band pass filters for each band (160-10M) and operating it outside of this region MAY burn "something" up.

I hope somebody else can give you better info.

Dick  AD4U
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W9GB
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Posts: 2579




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« Reply #2 on: February 16, 2013, 04:40:04 PM »

Dennis Cobbe, was the founder of Transworld Electronics (1975) based in Escondido CA.
He designed the Metron HF amplifiers because, as an avid radio amateur, he was unsatisfied with the HF amplifier selection for amateur radio in the 1970s.  The Metron product line was based on a Transworld government/military product lines.

Interesting story about Dennis Cobbe's youthful adventures.
http://ketekawerau.peoplesnetworknz.info/sir_james_fletcher_kawerau_museum/topics/show/57-television-comes-to-the-bay-of-plenty

Dennis sold his company, Transworld to Datron and continued to work there for a few years.
He passed away (sk) in 1997.  Helge Granberg (designer of Motorola solid-state RF transistors) had died the previous year (1996).

The Metron 1000B HF amplifier was also known as a Transworld MA1000.
The Transworld amplifiers were 28 VDC powered and used house marked MRF-422 RF transistors.  
The Metron ampliiers operated from 12.5 VDC (mobile capable), so it used the MRF-454 RF transistor.
Datron World Communications no longer supports these amplifiers (NO manuals, parts, schematics, etc.).
There are a couple of Yahoo groups that focus on support for these units, this is the Transworld Yahoo group.
http://groups.yahoo.com/group/transworld_radio/

The Metron 1000B used four, two device (MRF-454) modules with combiners and 6 bandpass filters, and could be fully remoted.  Although the WARC bands were not listed on the bandswitch, it has been reported that the 1000B model will cover them.

This 1000B model has these known drawbacks.
http://www.k0bg.com/amplifiers.html

1. There were no cooling fans and unless you wanted to replace the finals on a regular basis,
you had to add fans to increase cooling.
2. The input circuitry used swamping resistors to reduce the drive power to the finals.
3. If you find one of these used, make sure it works perfectly.
.
« Last Edit: February 16, 2013, 05:03:13 PM by W9GB » Logged
AD4U
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Posts: 2150




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« Reply #3 on: February 18, 2013, 09:04:58 AM »

I only recommended that you be very careful using this amp on the WARC bands because if you blow the finals, you may as well use the amp literally as a boat anchor.  The finals are not available at any price.

I had a Metron amp for around 15 years and it never missed a beat.  Used properly a Metorn will last forever.  Still wish I had it.

Dick  AD4U
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W9GB
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Posts: 2579




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« Reply #4 on: February 18, 2013, 10:46:38 AM »

Quote from: AD4U
I only recommended that you be very careful using this amp on the WARC bands because if you blow the finals, you may as well use the amp literally as a boat anchor.  The finals are not available at any price.
Dick, this is old information from a decade ago (when Motorola was divesting operating divisions).  
There was a short period of time, when Motorola was not producing the MRF-454.

The CCI EB-63A amplifier kit uses the MRF-454 RF transistor!!
http://www.communication-concepts.com/index.php/amplifiers/eb27a.html

The MRF-454 RF transistors are still manufactured (MA/COM) and readily available from Communication Concepts, Inc.  MA/COM acquired production rights for the legacy Motorola RF transistors (2007) as part of the Motorola/Freescale/SiRF divestitures.  $81.50 for a Matched Pair.
http://www.communication-concepts.com/index.php/components/rf.html?p=2

MA/COM Datasheet for MRF-454, July 2007
http://www.communication-concepts.com/index.php/fileuploader/download/download/?d=0&file=custom%2Fupload%2FFile-1339373857.pdf

You can also substitute the 28 VDC MRF-422 transistors (which are still mfg.) --
then it is identical to the Transworld MA1000.  $145.90 for a Matched Pair
http://www.communication-concepts.com/index.php/components/rf.html?p=2

While you could not use this converted Metron amplifier (MRF-422) as a mobile (12 V),
it could be a base station amplifier with appropriate 24-28 VDC power supply.

The Transworld Yahoo group can provide additional details on the MA1000.
http://groups.yahoo.com/group/transworld_radio/
« Last Edit: February 18, 2013, 11:12:20 AM by W9GB » Logged
AD4U
Member

Posts: 2150




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« Reply #5 on: February 18, 2013, 12:03:44 PM »

I guess that is what I get from repeating what I have read on the internet! 

Like the TV ad says, "He is a French model.  I met him on the internet.  We all know that if it appears on the internet, it must be accurate."

My error and I am glad the MRF454 is still with us.

Dick  AD4U
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VA3PWC
Member

Posts: 2




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« Reply #6 on: March 01, 2013, 07:33:22 AM »

Hi folks

I do have the TWE T500M (also Metron 1000B)... I have been used this for couple months on WARC bands without any problem. Don´t worry about finals, because MRF454 is still available and cheap in RFParts. In case if you want to replace them you can also use the 2CS2879, so you can have a little more power out. 2SC2879 is cheaper than MRF454 in case you want to get those.

Honestly, this amplifier was built like a tank and I have operated in some contests. Very good quality material (not chinese stuff). It´s an american made quality built in the 70´s.

I spent using that amplifier specially on 17 meters CW.

Just pay attention with HIGH SWR. Otherwise you can blow the final transistors.

On 17 and 12 meters with 50W input, this amplifier delivers 500W easy.
On 30 meters meters with 50 W input,it delivers 550W.

Go grab one if you find one...

best regards from Rick PY2EL / VA3PWC
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W9GB
Member

Posts: 2579




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« Reply #7 on: March 06, 2013, 04:30:27 PM »

Quote from: PY2EL/VA3PWC
On 17 and 12 meters with 50W input, this amplifier delivers 500W easy.
On 30 meters meters with 50 W input,it delivers 550W.
Rick can operate that RF power output, BUT in the United States we are limited to 200 watts PEP on 30 meters.

Throughout most of the world, the 30 meter band cannot be used for phone communications except in emergency situations. However, part of Region 1 (Africa, south of the equator, during daylight hours) is permitted to use phone. The USA limits amateur radio users to 200 watts peak envelope power on this band.
http://en.wikipedia.org/wiki/WARC_bands
« Last Edit: March 06, 2013, 04:32:50 PM by W9GB » Logged
VA3PWC
Member

Posts: 2




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« Reply #8 on: April 14, 2013, 11:15:32 PM »

Yes, I agree with you.
On 30 meters band we can only use 200W output.

I mean that the amplifier can deliveries some power on 10 MHz. Of course, we are allowed to run only 200W on that band.

thanks for all explanations.

73
Rick PY2EL
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