July 5, 2016 External Bigmeter

The external decameter was designed to switch between the built-in and external when plugged into the rear jack, but I made it so that the internal one also runs at the same time. It's a 12cm x 10cm dual decameter with a black needle and a red needle.

June 25th: Boxed and ready

Cased front panel (at 1KW transmission)　　　　　　　　　　　　　　　　Final circuit diagram of MAIN

Inside the case	Back Panel
	A FWD/REF decameter can be connected as an EXT (external) meter.

You can expand Robocon to multiple units (band switching). The knob on the bottom right of the panel is for band switching.

May 26th: Manual revision (Version-1.4)

Manual revised version (Version-1.4)　　　 The panel design drawings have been completed and are expected to arrive in approximately 10 days.

Dynamic detection of FWD/REF detector 　Manual Revision

Connect a manufacturer's power meter (that can check reflected power) at the same time, and set the output power to 50W or 100W or whatever, as long as you can check the REF. At the same time, connect to the dummy through a coupler you have. Output power with a single tone, intentionally shift the matching with the coupler, and check that the REF meter increases or decreases. At this time, it is OK if the bottom point of the REF is almost the same on the manufacturer's REF meter and this unit's REF meter. If there is a difference, increase or decrease the number of turns (design value = 27t) of the detector's T1 and check again.

SWR characteristics

April 19th: Case study and 1KW operation

I am considering using Takachi's free size case. I have received a quote from Takachi because they can do drilling and silk screen printing on one unit. I plan to try it on one unit.  Hole processing diagram　                                                                                         　Silkscreen printing

Normally, in manual operation of Robocon, high power tuning is not performed immediately. In my case, the linear amplifier is ON, the exciter PCON is set to minimum, and the output is around 200W. I tuned at 200W once, then tuned at high power. It is safer to operate Autotune in the same way. In other words, in conditions where the REF range exceeds the 20W range and you check it at the 200W range, there is no problem if you set it to low power once and the REF range does not become full scale at the 20W range. Left meter = FWD, right meter = REF. The video on the right is an Autotune video from the 3.550MHz tuning point to 3.605MHz. It starts with 200W power, and at the start point (3.605MHz), REF = 35W, SWR = 2.4. Since it is moving to a higher frequency, it is fine if the L-MOT moves steadily in the UP direction. At first, the REF range is 200W range, and the REF value decreases due to the UP operation. Next, the REF range switches to 20W and the REF value drops, and finally the REF range switches to 2W and drops to undetectable. At this point, REF=0.000W, SWR=1.00, and it is 'complete', but if you try sending out 1KW at this point, REF=0.4W, SWR=1.02. Of course, there is nothing wrong with this, but it's no fun to see it swing. My Robocon takes about 35 seconds to move between these two points.

This is a video showing the Autotune movement from the 3.550MHz tuning point to the 3.605MHz tuning point.

So, when I tried to run Autotune again at 1KW, it became undetectable, REF=0.000W SWR=1.00, the needle stopped swinging, and I felt refreshed. It took about 9 seconds at this point.

This is a 1KW-Aytotune video at 3.605MHz point.

This is the operating state after 1KW-Autotune.

April 14th: How to make a meter sill

It's in the computer section. It's an ELECOM photo sheet. The number you're looking for is L11, model number is EDT-PS4.	You can take 4 pieces per sheet. For Akizuki Meter, W = 4.7cm, H = 3.5cm

I have attached the original JPEG file without the callsign, so please right-click and 'Save target as' and use it as you like. There are also designs proposed by local stations.         　　Plan A 　　Plan B

April 9th: Autotune in action

The basic operation is as shown in the right figure. Ideally, it is the same as the ACN operation, but it is desirable to extract points A and B and set (A-B)/2 as the operating point. However, due to the time required, it is currently possible to extract one point and set it to the bottom point of the REF value by back processing. The optimal value for Back-Time varies depending on the speed/gear ratio of the control motor. Install the actual device and after completing Auto, manually operate to confirm that it is indeed at the bottom point. If it is not aligned, tune by increasing or decreasing the Back-Time setting. It should be OK once you set it, but we will continue to identify and improve problems while operating it. In the future, I will link it to a homemade exciter and start it in 'AUTO' to automatically send out a single tone and automatically stop it after completion. My Robocon takes about 30 seconds to move from 3.605MHz to 3.540MHz. Each station's Robocon is quite fast, about 10 seconds. I tested it from 3.58MHz to 3.540MHz depending on the time of the video. Tuned at 3.58MHz, at 3.540MHz the SWR is about 1.7 to 1.8. (My antenna is a CD-78L.) Below is a video showing how to autotune to this point.

Use the 'SEL' key to select either Auto mode or Normal mode, and by selecting Auto and pressing the 'ENT' key, Autotune will start. However, before starting, make sure that you are outputting a single tone/carrier or two tone with at least 15W or more.

If there is no signal output when starting, or if the output is less than 15W, the following error will occur and the device will stop.

At 3.540MHz, the tuning is off and it starts from the starting position (SWR=1.82). I tested it with FWD=20W.

When Autotune is complete, the following will be displayed.

After OK, I checked the output with 20W single tone in normal mode. I haven't checked it with high power yet (because I'm scared). I'll do that later.

By pressing the 'Z-DW' + 'L-DW' keys and turning the power on, you can change the Back-Time value. Set in 100mS increments.

[Autotune video explanation] There are two LEDs (red and green) in the middle; red lights up when L-UP and green lights up when L-DW; they do not light up unless current is actually flowing through the motor. �@Press the 'ENT' key to start. �ADetermines the direction. When L-UP (red light turns on), REF increases and the direction is determined as L-DW. �BWhen L-DW is in operation, the light turns green, the REF value decreases, and the SWR decreases. �CDetects when the REF value reverses (increases). �DBack-Time operation, in this case L-UP (red LED lights up), in my set Back-Time＝15X0.1＝1.5S. �EClick "Complete=OK" to finish.

Click to play video of Autotune in action

April 1st: Assembly completed

After adjustment and operation check, the circuit diagram and parts list have been updated. Autotune operation needs further verification. 　Circuit Diagram 0401　　　　Parts list 0401　　　manual　　　General Wiring Diagram

Main board: Component side (VR1 is printed incorrectly as VR3)	Main board: Solder side (backed with ceramic 103, see circuit diagram)
DISPLAY　Component side (Only Key/LED/LCD installed)	DISPLAY Solder side: Cut the legs of the connector parts located under the LCD short. (They may hit the LCD and float.)
At the sensor detection outlet, I mentally wound 5T around the toroidal core.

With all the wiring done, I was emitting a 1KWpep 1T signal. REF was 0 (SWR=1.00) even in the 2W range.

March 31st: PWB arrives

We started assembling immediately, and first assembled the FWD/REF detection unit. We connected it to the barracks and confirmed that it was working as designed. There was no dependency on the frequency characteristics from 3.5MHz to 28MHz, and PEP detection was possible. We will check the data for details after the entire assembly.

Fabrication of FWD/REF detector

The FWD meter and REF meter use Akizuki's 100uA ammeter. This is a sticker to be attached to the meter board. Dimensions: 47mm x 35mm printed. Please insert the call sign of each station.

March 20th: PWB artwork completed

It's been delayed for various reasons, but since it looked like it could be used in the preliminary verification, I've been designing the PWB artwork, and it's finally finished. I'd like to release it next week and get it up and running quickly. There are two types of detection units: a FWD/REF detection unit and a MAG/PHASE detection unit. The FWD/REF detection unit was created as a PEP power (FWD/REF) meter and an SWR meter, and will soon be used as a CD78 Robocon controller (Autotune operation). The MAG/PHASE detection unit will be used in the future for Autotune of various antennas and linear amplifiers. It's still in the middle stage, but I thought I'd try it as a measuring instrument too. Therefore, for each detection unit, I will create a sheet so that two units can be created as a board configuration for future consideration. The board configuration is as follows. Also, I thought about what to put in the blank area due to economical dimensions, and I added an OPA2677 board that can be used by all stations (it won't get in the way).　　　　　　　　　　　　　　　　　　　　　　　　　　　Circuit Diagram　　　　　　　　Bill of Materials

The detection unit consists of two units.

Component surface pattern Solder surface pattern Parts side silk printing FWD/REF detection board (unit) Takachi (TD8-8-4N) used MAG/PHASE detection board (unit)

【overview】 　The 3.5MHz band is not a continuous frequency range as an extended band, but rather an extended area from the previous area (3.50MHz to 3.75MHz) as shown in the table below, with the Tobitobi frequency being a wide band of 3.50MHz to 3.805MHz = 305KHz. 周波数 帯域 3.50MHｚ〜3.575MHｚ 75KHｚ 3.599MHｚ〜3.612MHｚ 13KHｚ 3.68MHｚ〜3.687MHｚ 7KHｚ 3.702MHｚ〜3.716MHｚ 14KHｚ 3.745MHｚ〜3.77MHｚ 16KHｚ 3.791MHｚ〜3.805MHｚ 14KHｚ It is difficult to create an efficient antenna that is perfectly tuned across all frequencies for such bands. Also, because the frequency is low and the length is λ/2 = 40m, it is even more difficult to create a full-size antenna. CD has an antenna called 'CD-78' that can be used in a small space even under such conditions. I have been using this type of antenna for many years. The CD-78 is a shortened antenna and the tuning band is very narrow. The manufacturer has made it possible to switch the band in four positions at the power supply point directly below the antenna using a relay. However, while this allows for narrowband support at four points, it is not possible to do so over a wide band. Therefore, various couplers directly below the antenna that can be tuned at any frequency have been created for such shortened antennas. A station manager I know, JA3WAO/JA2LUT, has made many improvements and created what is commonly known as 'Robocon'. The results are used as a reference by various stations to create their own antennas. I met JA2LUT at the grounds when he was alive, and he gave me the impression of being a very gentle person. I'm very sorry that he passed away two years ago. That's enough of the introduction. Although I didn't make it myself, I have something called 'Robocon' installed directly under the antenna, so I'd like to briefly introduce it to you. 　Click to enlarge.　The brass cup moves with the left and right rotation of the motor, changing the L value. At this time, a potentiometer is attached, tracking the movement of the brass cup. This allows presetting, and it is possible to move the position indicator to a specified frequency. However, this potentiometer becomes gallium and blinds the user (of course, this can be easily replaced). Manual tuning is not troublesome, but this time, I will build a power meter that can simultaneously monitor FWD-Power, REF-Power, and SWR in real time with a PEP power meter, so I decided to include an automatic tuning function for this coupler as a bundled function. 【specification】 �@　The FWD-Power meter is an analog meter with three range settings: 2000W, 200W, and 20W. �A　The REF-Power meter is an analog meter with three range options: 200W, 20W, and 2W. �B　The SWR meter is a digital display with two decimal points. �C　FWD/REF/SWR can be monitored simultaneously in real time. �D　FWD and REF have independent range switching. �E　With auto-tuning auto-start function, 20W or more carrier or single/two-tone. �F　Supports 2KW (actual capacity = 3KW). Can also be calibrated to the 3KW range. �G　Added UP/DOWN keys for manual tuning.

Panel image