Hermes Lite Superband Ver 1.3 Build Instructions

The boards are available from Oshpark under my callsign - https://oshpark.com/profiles/AC9HY

The BOM is on my github fork under the Softrock branch - https://github.com/W9JSW/Hermes-Lite/tree/Amplifiers/frontend/BPF%20Superband

The bom name is bom-superband v1.3.xls. The file named Band Configuration V1.3.xls contains the per band inductor winding instructions as well as the per band capacitor values.

I tried to be consistent in numbering of the per band values assuming they will be grouped as 160,80/75; 60/40,30/20 and 17/15,12/10. This makes it easier to install on the board. However, there is no reason you cannot make a 30/20, 17/15, for instance, you will just have to translate the filter positions accordingly.

Note: I will use 12V and 13.8V interchangeably, and am speaking of the same power line.

Heat Sink Preparation

My heat sink is a 60x60 sink with a 10mm height bought on ebay. Position the board with the top up on the heatsink and mark each hole. Use a center punch to mark the hole center. Use a #43 drill (or a 3/32 is ok) to drill 5 holes. Tap the holes with a 4-40 tap. Be slow and careful to not break the tap in the hole. I use WD-40 to lubricate the tap. You need to have around 1/8 to 1/4 in of the hole tapped. You could also use self tapping screws of appropriate size. The 4 corners use a 1/2in 4-40 screw and the center uses a 1/4in 4-40 screw. The corners also use a 1/4in nylon standoff of appropriate size.

This picture is the board with the top up positioned on the heat sink and what it looks like after marking.

This picture is a drilled and tapped board and what it looks like with the screws and standoffs.

Place SMT components

Place R10,R12,R7 - 270 ohm, R3,R9,R13,R14 - 4.99k ohm and R6,R8,R15,R16 - 10k ohm resistors.

Place R1,R2 - 499 ohm, R4 - 0 ohm, R5 - 6.8 ohm and R11 - 18 ohm resistors

Place D1 - Yellow LED. Orient the part such that the bar on silkscreen is on the same side as the green dots on the component. They are hard to see but they are really there! This LED will lite when Band pair 1 is selected.

Place D2 - Red LED using same orientation directions. This is the PTT LED.

Place D3 - Green LED using same orientation directions. This is the 12V power LED.

Place 1uf capacitors C17 and C28.

Place U1, the LD2951 regulator. Note orientation for pin 1 nearest the L10 writing on the silk screen.

Place Q1,Q2 - FDV301 MOSFETs.

Place 0.1uF capacitors C1,C2,C3,C4,C12,C15,C16,C18,C19,C20,C26,C29,C30.

Place D4 - TVS Diode.

Place FB1, the ferite bead.

Place C7 - 47uf Tantalum, C22 - 10uF Tantalum with bar oriented to plus sign on silkscreen.

Place C21 - 4700pf capacitor.

Place C5, C6, C8, C9, C10, C11, C13, C14 according to the selected bands per the chart in the Band Configuration spreadsheet. For stacked values, solder one of the capacitors first, then position the second one on top, and touch each side with the soldering iron, spreading the solder up to the second capacitor.

Wind Transformers and Install

Note - This is a picture of the 1.2 board. The T2 and T3 orientation is the same. T1 has been removed on v1.3.

Wind T2 using a BN-43-2402 with 4 turns of #32 wire for the primary, and 6 turns bifilar for the secondaries. Separate them out in 3 pair groups, with primary as one, one of the secondaries in the middle and the other secondary on the other side. Place the transformer in the T2 position with the primary in hole 1 and 2. Hole 1 is the square hole and hole 2 is to the left (see picture below). Place the secondary pairs in corresponding next holes. See the Basic Frontend build instructions for more details.

Wind T3 with 6 turns of #32 wire for the primary, and 4 turns bifilar for the secondaries. Separate them out in 3 pair groups, with primary as one pair, one of the secondaries in the middle pair and the other secondary on the other side. Place the transformer in the T3 position with the primary in hole 1 and 2, the secondaries in corresponding next holes. See the Basic Frontend build instructions for more details.

Place Top of Board Thru Hole Components

Install K1 and K2. Orient such that the bar on the relay is on the same side as the square hole. The 2 relays will be oriented opposite of each other.

Install P2, P3 and P4.

Install VR1 - bias potentiometer, with the screw oriented nearest T3. This is a 25 turn potentiometer. Use a screwdriver and rotate the screw clockwise until you hear some faint clicking. The bias will be set later.

Install the BNC connector. You may need more wattage to solder the heavy posts. Be careful to not heat it too much or you will melt the interior white insulator.

Wind Toroids and Install

Wind L10, the FT43-37 black toroid with 11 turns of #26 wire. A turn is one pass thru the hole. Scrape off the ends and tin them. Install the toroid erect in the L10 position.

Wind the 8 band filter toroids, per the directions in the Band Configuration spreadsheet, noting that the lower bands use T37-2 red toroids vs. the 37-6 yellow toroids. Scrape and Tin. Install.

Cut 3 inches of Rg-316 or RG-174 coax. Split 3/4 in of each end such that there is a 1.5 in center section of uncut coax as shown. Separate the braid from the center, orienting the braids 180 degrees on opposite sides.

Bend the coax in the middle as shown.

Insert into the BN43-202 binocular toroid.

Align such that the braid and center of one side goes into the corresponding holes on the top of the board - braid in large hole, center in small hole. Do the same with the other side. Solder. Be careful that some whiskers of the braid do not short out with the center conductor. See picture below.

You can stick the binocular down on the board in the marked square if you like. I suggest a dot of hot melt glue. I usually just leave it standing, lazy I guess ... hihi

Transistor and Heatsink install

Holding the transistor with the tab side down flat on a table, bend the pins up by 45 degrees. Bend on the wide part, not the narrow part, allowing about 1/2 of the wide part to be flat before the bend, as shown.

Place some heatsink compound on the transistor tab.

Take the board and insert the transistor under the board, oriented so the tab is visible in the large hole, and position it over the heatsink with the 4 corners aligned, and the middle hole visible thru the tab. Mount 2 of the corners on the heatsink, on opposite corners, using the 1/2in 4-40 screws and 1/4in spacers, leave loose. Use the short screw and mount the transistor on the heat sink and tighten. You may need to align the hole with the tab with a toothpick or scribe. Install the other 2 corner screws and tighten all 4 screws. You can now solder the transistor pins and trim.

Filter configuration in PowerSDR

Filters are selected using the J16 screen in PowerSDR. You have to place a 1 in the 5 column to turn on band group 1. The same data needs to be in both the receive and transmit sections. Thus, here is the screen with all of the bands configured for receive and transmit.

Filter configuration in QtRadio

QtRadio needs to be recompiled to allow for J16 filter switching. Contact AC9HY for more info.

Testing the board

Remove the basic frontend board if present. Plug the board into the hermes lite PCI-E connector. Attach an antenna to the BNC connector.

Note: This picture is of the v1.1 board, and has a few extra wire workarounds that are corrected in the v1.3 board (power feed and Ext PTT).

Build a 2 pin female molex power connector and attach to your 12 or 13.8V power source. Attach the 12V power to P4. Pay close attention to orientation of +12. Put an ammeter in line of the +12v power line. Set the meter to allow up to 2 Amps.

Power up the Hermes and the PA. The green LED should light. Note the amount of power being used. It should be minimal. Around 10 milliamps. If not, shut off and look for power shorts. Would be a really good idea to put a fuse of around 2A on the power line.

Launch PowerSDR and start it. You should see signals on the bands you selected for the build. When tuning to the lower band pair, you should see the yellow LED light.

To set the bias, install a dummy load on the BNC. You may also install a RF power meter in-line if desired. Go into SETUP and select the transmit screen. On the left is a box to set tun to drive power. Select that option. Press apply then close the setup dialog.

To set the bias, no signal should be present. Set Drive to 0 on the main PowerSDR screen. By setting drive to zero, we should only be turning on PTT but not actually driving the amp with RF. Press Tun on the PowerSDR screen and the red PTT light should illuminate. You should see minimal increase in current and no indication on the RF power meter if installed. If a noticeable change in current and/or RF power is indicated, resolve it, do not set the bias if signal is being send to the amp.

Rotate the VR1 screw counter clockwise until the current rises by 300-350ma. This may take 15 to 20 turns. Shut off Tun. Set the drive slider to 100. Press Tun and observe the power output. Depending on voltage used (12 or 13.8) you should see around 4-5 watts of power.

Note: On my station, I will power both the PA and the Hermes Lite from the same 13.8V feed. The 13.8V going to the Hermes Lite will connect to a power converter, then the outputs will feed 5V and 3.3V to the board. No 12v connection is needed. I have a ADC and power daughter card that provides 5v and 3.3v. You can see it on the W9JSW QRZ.com page.

Since the bias is set with a 5V regulator, there should be no need to re-bias if changing between 12V and 13.8V.

Have fun on the bands!

73s, W9JSW