[Motorola] RE: Motorola Tube Amps

Wed, 21 Apr 2004 12:18:18 -0700

Thanks for all the replies!

I have inspected the 2 tube amp in question (Low VHF Band) and unfortunately have found no model numbers, but there are no model numbers on any of my other amps either.  It does have several part numbers on different pieces, i.e. TFB6014A Harmonic Filter.  It is very clean though and looks like it has seen little service.  I do have some information on the 2 tube "high" VHF band amps.  I have 2 of these amps (TLD6613A) that I scooched down to 144.200 MHz.  They work pretty well at about 675 - 700 Watts RF out.  The information I have is in the form of a Motorola Engineering Publication, which describes the tuning and trouble shooting and has a schematic and parts list.  I also have the same publication for the single tube amps model TLD1191A and TLD1192A, again for the 2 meter band.  At one time I had an amp for the UHF band (1 tube version.)  But it did not work for me at the time and I converted it to spare parts, wish I had NOT done that now.

Mike, I would indeed be interested in any of the information you have, AND I am more than willing to supply any information that I have to anyone who needs it.  I can also snap some .jpg's of any of these amps if anyone is curious as to what they look like.

Thanks in advance for the assistance!

John
KA7CVJ

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Today's Topics:

   2. RE: Motorola Tube Amps (Mike Clarson)
   3. RE: Motorola Tube Amps (Glen Zook)
   4. RE: Motorola Tube Amps (Mike Clarson)
   5. MOTOROLA MICOM XR (federico)

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Message: 2
From: "Mike Clarson" <[email protected]>
To: <[email protected]>
Subject: RE: [Motorola] Motorola Tube Amps
Date: Tue, 20 Apr 2004 16:29:11 -0400
Reply-To: [email protected]

I do not recall a one tube version of these using the convection cooled tube--only air cooled. I do recall the 8072 one tube version for 450 MHz. The basic design of these 2 tube decks were quite similar thru the MICOR era. I have some info on the MICOR amps in 30-50 MHz range, so if you do not get a response for you exact amps, this may help. May have others also--will have to check. I do recall an article for modifying one of these amps for 2 meter SSB in one of the ham magazines but that is as close as I can get. --Mike, WV2ZOW

-----Original Message-----
From: [email protected] [mailto:[email protected]]On Behalf Of Kinney John-r17512
Sent: Tuesday, April 20, 2004 3:45 PM
To: '[email protected]'
Subject: [Motorola] Motorola Tube Amps

I have several tube amps, made by Motorola in the ' 60's.  These RF decks use convection cooled vacuum tubes (8560AS) in either 1 or 2 tube configurations.  Motorola apparently made these amps to cover multiple frequency bands.  I have a dual tube RF deck that looks like it should work around 50 MHz.  I also have 2 dual tube decks that work in the 2 meter band. Lastly I have 3 single tube decks that operate in the 2 meter band.  I am looking for anyone that could provide documentation on any of these amps or point me in the direction of an archive for this information.  Thanks in advance for your assistance in this matter.

John Kinney
KA7CVJ
Tempe, Arizona
480-413-4290

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Message: 3
Date: Tue, 20 Apr 2004 14:26:59 -0700 (PDT)
From: Glen Zook <[email protected]>
Subject: RE: [Motorola] Motorola Tube Amps
To: [email protected]
Reply-To: [email protected]

Motorola definitely made a number of the "single
ended" 8560A conduction cooled amplifiers.  These were
used in a number of the "upright" base station 100
watt continuous duty rated units from the late 1960s
well into the 1970s.  They were especially popular in
the 60 to 110 watt output high band repeaters that were
used on RCC (Radio Common Carrier) and IMTS / MTS
(Improved Mobile Telephone System / Mobile Telephone
System).

The 8072 is identical to the 8122 electrically.  The
8072 is rated at 75 watts plate dissipation (without
external heat sinking) and the 8122 is rated at 400
watts plate dissipation air cooled.  The cavity that
Motorola used in the 450 MHz base stations and
repeaters helped with the heat sinking and thus
increased the power handling capabilities of this
particular tube.

General Electric used a lot of air-cooled high band
amplifiers using both singe and dual 4CX250 and 4CX300
series tubes.  However, Motorola used very few air
cooled tubes in their upright base stations.  One
notable exception to this was the amplifier used in
the C74BBB, L74BBB, and J74BBB 100 watt (really a
beautiful 90 watt output 450 MHz base station - you
could load them to 100 watts, wait a minute or two,
and they would almost always fold back to 90 watts,
retune, and the same thing!) series which used a single
4CX250B.  Also, Motorola sometimes augmented the air
flow in the old "quarter-K" low band and high band units
(of which the later versions used the 4-125 / 6155
tubes) with a blower system.

Now, Motorola used all sorts of tubes that were
"cooled" only by the heatsink (thus were a combination
of conduction cooling and convection) like the 5894
and 8643 in various versions of the Motrac and Compa
base stations.  But these are not the tube types in
question.  As for "convection" cooled tubes, Motorola
used all sorts of them from the very early days!  In
fact, up until the Motrac (the driver tubes in all of
the Motrac were convection cooled and the exciter
tubes in the HHT series were convection cooled) series
all of the "normal" transmitters used convection
cooling!  In a few applications, convection cooling
was supplemented with some sort of fan to move more
air.

Glen, K9STH

Web sites

http://home.comcast.net/~k9sth
http://home.comcast.net/~zcomco

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Message: 4
From: "Mike Clarson" <[email protected]>
To: <[email protected]>
Subject: RE: [Motorola] Motorola Tube Amps
Date: Wed, 21 Apr 2004 01:50:56 -0400
Reply-To: [email protected]

Glen/John: My first reaction to Glen's post was (and I am referring to me, not Glen) "What an idiot" I was thinking conduction and wrote convection. Doh. Can't believe I never saw an 8560A single ended Motorola amp. But then I also do not remember working on any 100 watt IMTS stations on hi-band--only 250 watters. I do recall a 100 watt IMTS Motrac style base that used an updated version of the UHF BBB pa--100 watt with 4cx250. The dual 8560S amps lasted thru the Micor series except on UHF where Motorola switched to the single triodes in a cavity in the mid eighties. 800 MHz only used the triodes as far as I remember.

On the 8072: The Motorola amp used only the 8072 (Don't believe Motorola ever used an 8122. correct me if I'm wrong). Well, not exactly--it was a selected 8072, Motorola had a different number for that .. a 4??? something. too lazy to look it up. But I do recall that if one used an 8072 in a Motorola amp, it often would not make full power. But put the selected one in, no problem. RCA, however, never had a problem making 100 watts with an 8072. Odd, but it was their tube. RCA used the 8122 (as you said, an 8072 with cooling fins for forced air cooling) in the 1/4K UHF "Super Control-Phone 500". It had similar charistics to the 100 watt amp you described. Tune it up to 250 watts, and a few hours later it would stabilize at 175 and run there for months. Retune, same thing. I've been told the amp would work just fine at 250 watts if one adjusted all the bi-metal temperature compensating caps correctly. The full procedure took about 1/2 hour. Preferred the Motorola amps!

While the Motorola 2 tube amps worked well with power to spare, my experience was when the tubes failed the base would often be found in a no transmit condition. My two favorite amps, the 4-400 in the Quintron QT-350 Low Band (love the shorting stick), and the single 4CS-250 (conduction
cooled) high band amp in the QT-250 would fade away slowly eliminating many after hours calls.

Anyway, I do have tech info on the MICOR version of the 2 8560A amp for low band. John, if you can find any TL? numbers (like TLD-4010A ) we may be able to help with the frequencies these amps were designed for.--Mike, WV2ZOW

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Message: 5
From: "federico" <[email protected]>
To: [email protected], <[email protected]>
Date: Wed, 21 Apr 2004 07:29:18 +0100
Subject: [Motorola] MOTOROLA MICOM XR
Reply-To: [email protected]

Hi to all,
          I found my MICOM XR 12 as surplus from UNO, the transceiver is in 
good working order, my problem is how I can get access to programming steps 
so I can see (and eventually change) the numerical code that identify the 
equipment for SELCAL.

In the Tech. Manual that I got from MOBAT the first step needed to get 
acces to programming procedures is : press in the same time decimal point (.) 
and the down Key (V) and then FUNCTION key, in this way the tech. manual says 
that in the upper right corner of the display appears the word PROGR.

My equipment is the same of the Tech Manual (and send selcal if requested to 
do so) but don't answer to the first step.

I see that the display has some little changes respect to the tech. Manual :

(1)
instead of  "SEL" there is  "SELCAL"

(2)
if you push RX/TX button the display don't show RCV or TX, in other word the 
equipment operate only in SIMPLEX MODE (but this isn't a problem).

I suppose that my MICOM XR 12 don't answer to the programming steps because, 
probably, UNO asked some other options : military ALE instead of a simply DSC 
(the tech. Manual says Selective Call)?

Anyone can help me?

73 de Federico BALDI IZ1FID

Visit my webspace voted to military surplus radio and aircraft clocks :

www.dottorbaldi.it/militaryradio

See also :

http://www.geocities.com/pa0jta2/hamshacks.html

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