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Radio-Info.com Discussion Boards>RADIO PROS>Engineering>Be-AM1A or 500 frequency change
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Author Topic: Be-AM1A or 500 frequency change  (Read 935 times)
SuperQ
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« on: November 09, 2009, 02:02:42 PM »
Anyone ever changed one of these rigs in the field.  BE wants a lot of money plus the hassle of boxing it up and shipping it off.   Seems like it should be doable by skilled hands. 
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BobOnTheJob
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« Reply #1 on: November 09, 2009, 05:36:10 PM »
I hope someone answers this one...I know there are frequency sensitive parts on the schematic. Whether switching the exciter card & those components is all it takes is anybody's guess.
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When I started in radio in 1967, most broadcast equipment used tube technology, all recorded music was played from records on a turntable by live DJ's, there was no satellite delivery...and radio was fun.
Watt Hairston
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« Reply #2 on: November 09, 2009, 06:24:41 PM »
Not advised for several reasons: BE winds their own fixed inductors for each band and there is little overlap. The instruments necessary to precisely set up the networks are not very common in the field and I don’t think they even publish a technique or a parts list.
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SuperQ
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« Reply #3 on: November 10, 2009, 07:34:45 AM »
Thanks Watt.  I got that from a couple of other sources.  Bottom line.  It probably could be done.  But probably only by a pretty high dollar estimate.  I'll just box it up and ship it off...
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Tom Gary
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« Reply #4 on: November 12, 2009, 11:33:06 AM »
The RF output network of any transmitter is a complicated design. It must not only match the antenna load impedance but also provide the FCC required harmonic and spurious supression.
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BobOnTheJob
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« Reply #5 on: November 13, 2009, 01:40:06 PM »
Quote from: Tom Gary on November 12, 2009, 11:33:06 AM
The RF output network of any transmitter is a complicated design. It must not only match the antenna load impedance but also provide the FCC required harmonic and spurious supression.
On top of that, the BE's are fixed 50 ohm output...no tuning & loading controls making the RF output network even more critical...no controls to compensate for imperfections.
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When I started in radio in 1967, most broadcast equipment used tube technology, all recorded music was played from records on a turntable by live DJ's, there was no satellite delivery...and radio was fun.
BofH
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« Reply #6 on: November 14, 2009, 05:58:02 AM »
Quote from: BobOnTheJob on November 13, 2009, 01:40:06 PM
Quote from: Tom Gary on November 12, 2009, 11:33:06 AM
The RF output network of any transmitter is a complicated design. It must not only match the antenna load impedance but also provide the FCC required harmonic and spurious supression.
On top of that, the BE's are fixed 50 ohm output...no tuning & loading controls making the RF output network even more critical...no controls to compensate for imperfections.

Yes - highly recommend the optional Output Tuning Unit they offer to provide some control (especially useful if your Antenna/ATU takes a hit)
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BobOnTheJob
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« Reply #7 on: November 14, 2009, 09:15:22 AM »
The early AM1A's had Tuning/Loading controls built in. Don't believe the AM 500A ever did though.
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When I started in radio in 1967, most broadcast equipment used tube technology, all recorded music was played from records on a turntable by live DJ's, there was no satellite delivery...and radio was fun.
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