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Re: [Mw] Model 5112 Oscillator


This message will probably bounce when it hits the Amsat Reflector as I'm not subscribed
to it. If it doesn't make it, would you please copy them for me please.

Comments to your questions are in-line below....

At 04:19 PM 1/17/2004 +0000, Stan wrote:
>Hello JWM,
>I am impressed with the product.
>How wide of a swing do you have with the VCO ?   and still have +12 dBm output  ?

The VCO used in the Model 5112 has a frequency range of 4780 to 5356MHz. I spec
the Model 5112 for +10dBm min over the range of 4968 to 5184MHz.

>I can think of other frequencies:
>10,451.0 MHz RF with 144.0 IF LO = 10,307.0 div by 2 = 5,153.5000    for AMSAT RX only on P3E launch 2005

This frequency is possible with the Model 5112. It could be an option or replace one of the
current Freq options in the future.

>5,668.0 MHz RF, 144.0 IF,  LO = 5,524.0 MHz       AMSAT uplink for P3E launch 2005,   also uplink on AO40 now
>5,760.0 MHz RF, 144.0 IF,  LO = 5,616.0   terrestrial 5.7 GHz

The above two frequency options are mostly driven by my ability to get an inexpensive VCO
for these frequencies. To date I have not found any VCO that qualifies price wise to merit a
product that I can sell to Amateurs.  But I continue to look. NRE from my current supplier
is very expensive, and the quantity of units being shipped  right now don't justify the NRE.

>24,048.0 MHz RF,  144.0 MHz IF,  LO = 23,904.0,  div by 4 = 5,976.0 MHz,    AMSAT AO40 K band downlink
>               and new terrestrial calling freq according to IARU/ITU
>24,192.0 MHz RF, 144.0 MHz IF,  LO = 24,048.0 MHz,  div by 4 = 6,012.0 MHz,   terrestrial 24 GHz currently
>47,088.0 MHz RF, 144.0 MHz IF,  LO = 46,944.0 MHz div by 8 = 5,868.0 MHz  terrestrial 47 GHz ops
>80,640.0 MHz RF, 144.0 MHz IF,  LO = 80,496.0 MHz,  div by 16 = 5,031.0 MHz, terrestrial ops

I never envisioned the Model 5112 being used in the above four frequency options. Remember, every
time you double the frequency, you add 6dB to your Phase Noise. The proper way to achieve the best
performance Phase Noise wise, is to use a DRO (Dielectric Resonant Oscillator) in the 11 to 12GHz range.
The phase noise would be around the -95 to -110dBc/Hz area with a DRO. Then one could afford to
multiply into the 24, 47, and maybe the 80 GHz bands without sacrificing low noise performance
due to phase noise increases. But once again, DRO's are very expensive and would be out of the
price range of Amateurs. I am looking at this design and hope to find a solution.

>Is there any scheme to externally change the oscillator frequency,  so a band change can easily be made without poping off the cover ?
>Possibly BCD inputs, well suppressed, for external freq change to change bands.

When I designed both the Model 1152 and the Model 5112 PLL units, my primary intention was that
the units would be mainly LO replacements. At a later date, I might bring out an external frequency
switchable unit.

>Can you think of any scheme to allow CW, by keying the oscillator in beacon operation ?      normal CW, not FSK/CW.

Actually I am currently designing a X2 multiplier for the Model 5112 that will have the ability to perform as
a straight X2 multiplier for people that want to build their own 10GHz radios, and as a beacon unit when
used with the Model 5112. The Multiplier stage will have the ability to be keyed on/off using an
external TTL input signal. This will be a true CW signal using the design I'm working on. Power output
should be around the +10dBm level. A Microprocessor keyer is also planned that will have the ability
to be programmed using a RS-232 input to program the message for the keyer. A message length of
around 32 characters will be possible.

>Thanks for considering these ideas.

Thank You for suggesting them. I need feedback from people so I can decide what the next product
might be. Your input is greatly appreciated.

Jerry Mulchin - N7EME
JWM Engineering Group

>Stan, WA1ECF
>Microwave mailing list

Jerry Mulchin - N7EME
jwm Engineering Group
e-mail - jmulchin@employees.org
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