Copper Talk » Open Forum » Archived Messages » 2002 » 09/01/2002 to 09/30/2002 » Can anybody tell me what I bought « Previous Next »

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Chris142
Posted on Monday, September 23, 2002 - 11:31 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

I stopped at a garage sale saturday.Mixed in with the old 23 channel CB's was a linier.I bought it.Paid $10.00 for it,figured that if it didn't work no big deal.On the outside it has 3 switches "power" "am/ssb" and "preamp".It's made by "triad-utrad" "model La-101".

The #'s on the finals are "trw,pt9784 7622 c"there are 2 finals.

How many watts should it do? OOOOH, btw it looks unmolested :)
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Taz
Posted on Monday, September 23, 2002 - 11:56 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

hehe, toss it on the meter. sounds like a fairly older one
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Tech671
Posted on Tuesday, September 24, 2002 - 5:36 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Around 150w output, usually takes fairly low input drive.
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ChillyDog
Posted on Tuesday, September 24, 2002 - 11:04 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Chris142,

The description you provided of the power transistors in your amp triggered a memory for me.

The date code on your transistors (that's the 7622) indicates they were manufactured during the 22nd week of 1976. The HF power transistor application engineer for TRW during the middle 70s was a great engineer and funny person named Steve Chambers. I was fortunate to work with Steve at a different company in the early 80s.

Many of the common design elements on HF transistorized linear power amplifiers sold during the late 70s and early 80s were developed or improved by Steve. Stable active biasing, optimized degenerative feedback, broadband impedance matching, temperature stabilization; he found creative and inexpensive ways to implement these features into commercially viable products. It's too bad that most current amps don't utilize his innovations.

Steve was also instrumental in some of the Space Shuttle communication systems, and was a strong contributor to microwave engineering in radar-guided missile systems.

Unfortunately, Steve died in the middle 80s, right around the age of 40. A tremendous loss to RF engineering, and to his friends and family. He taught me a lot, but maybe the best of what I learned from him was to try to keep a sense of humor.

I'll never forget the meeting where he told a missile system program leader (i.e.; his bosses' bosses' boss) that the only reason he was top s__t was because sometimes s__t floats ...

Best Regards to all, and to Steve, if you're listening: "____ me silly with a handy-billy!"

Bob
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jyd
Posted on Tuesday, September 24, 2002 - 5:44 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

the older the better
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Taz
Posted on Wednesday, September 25, 2002 - 1:16 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

are you saying a commodore 64 is better than a dual xeon server?
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bruce
Posted on Wednesday, September 25, 2002 - 1:41 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Taz I still have one it works fine a bit slower than my p3/866 with 1 gig ram
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2600
Posted on Wednesday, September 25, 2002 - 4:39 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

This little amplifier was a real firecracker in its day. Mobile radios back then typically would bust a gut to key 3 watts and swing to 12. If you have a radio that small, it's good match to the amplifier. Most of these we have seen over the years needed to have resistors installed in the drive circuit to reduce the radio power that reached the transistors. Cutting it by 3 db to 6 db (half or three-quarters) of what the radio delivered was about right for modern stuff that swings 20 or 30 watts. All that power gain is just too much of a good thing. It was a GREAT match for the external antenna jack on a 2 or 3-watt walkie-talkie. Made them large without being overdriven.

73