Sputnik St. Joe's High School
Radio Club

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Rich Robbins

St. Joe's Class of 1958

Rich Robbins first got the (novice) call WN8VNE, freshman year about October or November 1954, in the St Joe's High School Radio Club in Cleveland. He moved up to Technician W8VNE in sophomore year, followed by General Class later that year 1955.  He was one of the "Sputnik Trackers" in 1957 and graduated with the Class of '58.

By 1962 he was living in Pittsburg and got the call K3VJS.

Subsequently he moved to Australia, and from Sept, 1966 operated as VK3ARR with donated WWII-era equipment,

"but at least I was on air on HF and eventually upgraded to a Yaesu FTDX400 and a three element 20m beam and full wavelength 80m antenna."

"VK3RR was obtained in 2007 under a call sign reassignment by Australian regulatory, and my activity was moving to VHF & UHF, with developing interest toward EME."

Rich has always been quite a hands-on component-level experimenter and kept up with the latest devices, frequently obtaining "samples" from the various manufacturers.

In 2013, he started building a solid-state 1.3 GHz amplifier for EME, using the latest devices.

Here are pictures of the type of gear he continues to build up and the results of his on-going adventures.  Our hope is that someday someone from the club will make an EME contact between his QTH in Australia and "the States", maybe even Cleveland.

Rich VK3RR 1296EME Setup
Here's Rich with the large dish.   On the table is the 1296 Amplifier he built, and the moon is coming into view!



Here's the dish aimed at the moon
Here's the dish aimed at the moon.






Rich sent this report about the test on Nov 15, 2016:


Frequency spread/error
Signal Plot

WSJT-X Chart
WSJT-X Chart

I was using WSJT-x to control the frequency of transmit and receive on the TS2000 using the CAT control option.   The software in ECHO mode looks for the signal to analyze, and manages the Tx (up) freq and the Rx (dn) freq to deal with the doppler shift, --and it did it so well, with all the variables considered.

The received signal was within 2~4 Hz . . . That larger variation is seen on the graph at the bottom of the signal’s plot; see the 4Hz spread of signal variance.

The top of the graph is in Hertz, where “0” is the operating frequency of 1296.100000 MHz.

Note, this last transmission was at 1296.099024 MHz to cope with the up frequency for doppler correction.

The statistical information is hard to read, but the last three columns DF (Difference in Freq) 0.0~0.4Hz, Signal Width of 2.6~2.9 Hz, and signal reliability “Q” being in the "6" to "7" range and 7 is quite a good result. With a “Q” of 3, a signal is considered within the probability range.

There were 21 ECHO events of 6 seconds each that generated this plot.

Near midnight, I had one power supply weaken under the pressure of the surge demands of 2 sec transmissions every 6 seconds at 500W.   I did many more than a 1000 pulse transmissions.    We met our hopes that were just starting to actually hear a tone from the speaker from the reflected signal.

Yabba Dabba Dooooooo !!!  Mission accomplished.... 4 yrs of prep and 1 hour of "success".

Cheers, Richard


Early Mechanical Construction Fig.1



Dissecting the 600 Watt Amplifier:


So, What's inside the 600 Watt Amplifier with Power Supplies?

Let's "take it apart" and look at the assembly in somewhat reverse order!


Fig. 1  

This is an early stage of the mechanical construction with rear panel featured, two of the (4) 150W power amplifier modules (green boards on heat sinks), and the top shelf with the sequencer and its 12V power supply.








Fig. 2  

This view features the front panel, and the other two of the (4) power amps (green boards on heat sinks) in the assembled frame.


Eaarly mechanical constructions Fig 2

Early Mechanical COnstruction Fig.3








Fig. 3  
Going back further, this shows how the amplifier boards are mounted to finned aluminum heatsinks, and how the fans are mounted on the rear to move air over the fins of the heat sinks.

On the end opposite the fans, Note the "black box" at the top. That is the coaxial antenna relay seen in the next view.








Fig. 4  

This is a 180-degree view from Figure 3. and shows a much earlier partial assembly to confirm aspects of the overall design assembly, including the 4-input combiner board and its output connection to the coaxial antenna relay.

Note the use of "Type N" connectors.

Earely Mechanical Construction Fig.4

Early Mechanical Construction Fig.5







Fig. 5  

This is the Temperature/Thermal Indicator Board with LED's that mounts just behind the front panel.  This was a test to confirm the sensors and indicators were all in expected working order.






Fig. 6  

This is the back of the front panel with the Thermal Indicator mounted, and the backs of the analog meters.



Early Mechanical Constuction Fig 6,

Early Mechanical Construction Fig 7.


Fig. 7  

This is the top shelf of the amplifier with the Sequencing Control board and 24V control for the Antenna Relay.

The Sequencer performs five significant steps when the PTT (Push-to-Talk) Transmit button is pressed.

1. Turn off all receive preamplifiers.

2. Switch the relays for coaxial-antenna and RF-input away from the Transceiver.

3. Turn on 28VDC to all 4 amplifier modules, and their driver amplifier.

4. Tell the Transceiver it is OK to transmit.

5. Turn on the audio (Digital Transmission Audio fed into MIC Input).






Fig. 8  

Side view pf the completed amplifier showing 2 of the 4, 150W power amplifier modules (center, green boards), connected to the Output Combiner board (right side) where the outputs of all 4 amplifiers come together to make 600 Watts.






Early Mechanical Construction Fig. 10







Fig. 9  

Bottom View: This is the Driver Amplifier providing 40W to the power splitter/distribution module ON the left.







Fig. 10  

This is the assembled 28-Volt power supply showing 4 x 28V 20-Amp Modules.   Rear Fans are just visible inside (right).  On Left, front panel has LEDs for the output of each power module and the 240VAC Main On/Off Switch.




Early Mechanical Construction Fig. 11







Fig. 11  

This is the overall 28V power supply assembly showing some of the internal wiring.







Fig. 12  

This is the completed unit with the RF amplifier modules up inside the top.  

The upper red strip is the 5-LED sequence indicator.  

The 20-LED group displays the thermal staus of each group.   There is one 10-Amp meter for each amplifier.  

Lower down is a 10-Amp meter and a 28V Meter.  

The 1/4 inch stereo plug is from the PTT (Push-to-Talk) switch.  

At the bottom is the power supply with 1 LED indicator for the output of each of the five power supplies, and the 240V power On/Off switch.


Finished Unit, Fig.11

Output Spectral Display







Fig. 13  

This is the output Spectral Display at Full Power, 1293 MHz, 10 MHz Span, showing a clean signal!


---updated Oct 15, 2017 --

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