I appreciate that the last post here was about the HamClock and I said I wouldnβt be providing a guide to building one but Iβve been asked by a few people if I can write some instructions, showing whatβs needed from start to end so Iβve decided to do it. This is a long guide [β¦]
The post How to set up a HamClock for your shack first appeared on QSO365.Hereβs a little project I put together on a whim about 18 months ago. It was my tribute to the unlicensed (i.e. pirate) beacon cluster around 4096 KHz. There were several of them operating in full force, with powers ranging from around 100mW to a watt or so a few years ago. Their heyday was about 20 years ago. They were located somewhere in the southwestern deserts of the US, and were powered by batteries and solar panels. The feller who placed and maintained them has stopped their upkeep and, as a result, most, if not all of them, are no longer operational. (There was a small group who also placed these beacons, and I believe they too stopped doing so years ago).
This little beacon, using a commonly available crystal, put out around 30 or 40mW, if I remember correctly, into a 51 ohm resistor as a dummy load. If it were to be connected to an antenna, which will not happen at this frequency, it would need a low pass filter. I havenβt posted the schematic here, for two reasons β
Iβm posting the photos as a reminder that if you donβt have Manhatttan pads, or donβt want to make your own, then so-called βugly constructionβ is a very viable way of putting circuits together. If you do it well, your circuits can be quite robust and long-lasting. One of Rexβs MePADS was used for the IC, but everything else was built ugly-style.
In the next overhead picture, you can see the ATTiny85 that keys the transmitter. Above and to the right of it, is a 78L05 that supplies 5V to the chip. Directly below the crystal is the oscillator transistor, which is keyed by the transistor to the left of it. On the right is the PA transistor. All 3 transistors are 2N3904βs.
Before ending this post, there is a key part of ugly construction that is worth mentioning. High value resistors (1MΞ© and above) can be used as standoffs. To circuit components, they look like insulators. In this circuit, there are two 1MΞ© resistors used for this purpose. I later bought 200 x 10MΞ© resistors from Mouser, and will be using them as standoffs in the future. They wonβt increase your current draw by any significant amount either. A 1MΞ© resistor to ground from a point at 12V potential will only cause an increase in current consumption of 0.012mA. A 10MΞ© resistor will have even less of an effect, incurring an increase of just 0.0012mA. Thatβs 120Β΅A. I can live with that!
Anyway, thatβs it. I hope this inspires you to get the soldering iron out and build a little circuit. A simple receiver or transmitter, a novelty circuit, or anything really. Building these little things and getting them to work is fun. Incidentally, if youβre interested in listening out for these unlicensed HF beacons, the best source of information is the forums at HF Underground. The forum youβll want is the one called βHF Beaconsβ though there are many other great sub-forums there as well.
A few weeks ago I bought the official Raspberry Pi 7β³ touchscreen display for a project which sadly didnβt work as intended, this left me with the unused display and a case. I started thinking about things I could use it for and settled on a shack clock. Long term readers of my site will [β¦]
The post How to build a shack clock using a Raspberry Pi and a 7β³ Touch Display. first appeared on QSO365.After much research, Iβve decided what Iβm going to replace the Hexbeam with. Iβm aiming to put up a SteppIR UrbanBeam which will give me the same coverage as the Hexbeam with the addition of a folded dipole on 30m. At the same time, Iβm going to replace all the coaxial cable with Messi & [β¦]
The post New aerial β Iβve decided! first appeared on QSO365.
6m Antenna choices on the Station Master Deluxe
The next step in our project is to configure our microHam station management system to support the new antennas and other components in our 6m antenna project. Each radio in our station (we have five that are 6m capable) has a microHam Station Master Deluxe antenna controller that is used to select and control all of our antennas. These units use the band selection and frequency data from their associated Transceivers to present a set of antenna choices and associated rotator, LNA, amplifier, and other controls to the user.
We are adding the following components to our 6m antenna farm that will need to be controlled by our microHam system:
Any of these antennas and their associated Preamp Housings can be used by any of the six Transceivers in our station. There are also two Elecraft KPA-1500 1500w amplifiers (one is shared) that operate on 6m and can be used by three of the five Transceivers in our setup. In this article, I will cover the configuration of our microHam system to support all of the new elements.
microHam TEN SWITCH
I choose a microHam TEN SWITCH to handle switching between the new 7-Element LFA and the 6m Antenna Stacks that we will be installing. This switch is can be mounted outdoors on our tower and has good SWR, power handling, and loss performance at 50 MHz. I also chose the option to have N-connectors installed on our TEN SWITCH.
microHam Control Boxes β Relay 10 (Ant. Switch) & Relay 6 (Preamp Housings)
The first step in this part of our project was to install two new microHam Control Boxes to control the new remote antenna switch and the two 6m Preamp Housings. These control boxes are connected to a control bus which allows the Station Master Deluxe antenna controllers associated with our transceivers to control all of our equipment and antennas. The microHam TEN SWITCH that we are using requires ten 12 Vdc control lines to select one of its ten antenna inputs. Each of the two 6m Preamp Housings requires a combination of two 28 Vdc control lines to manage its relays and a 13.8 Vdc line to power its LNA. The microHam Relay 10 Control Box is a good choice for controlling the antenna switch, and a single microHam Relay 6 Control Box can be configured to control the two Preamp Housings. I installed the two new control boxes and a DIN Rail Terminal Block for ground fan out on an existing section of DIN rail in our shack. Finally, I extended the microHam control bus to the new units and connected the control boxes to the 13.8 Vdc and 28 Vdc power systems in our shack, and set the addresses of the two new control boxes.
Relay 10 (Ant. Switch) and Relay 6 (Preamp Housing) Control Box Configuration
Next, we updated the firmware in the new Control Boxes. We configured their relays into groups for interfacing to the remote microHam TEN SWITCH and the components in the 6m Preamp Housings.
microHam Ten Switch on Tower
The next step was to define βRF Boxesβ in the microHam program for the 7-Element LFA, three fixed-direction 3-Element LFA Antenna Stacks, and the two 6m Preamp Housings that we are going to be installing on our towers.
With this done, we created an additional RF box for the microHam TEN SWITCH that will be located on our main tower. The image above shows how the switch is configured in the microHAM system. We also needed to associate the Relay 10 control box with the switch to enable the microHam system to control it.
6m Shared Preamp Housing.jpg
The next step was to configure our 6m Preamp Housings. The image above shows the configuration of the shared housing installed on our main tower behind the microHAM TEN SWITCH.
Station Antenna Switching Matrix
The shared Preamp housing will be connected to one of the inputs on our antenna switching matrix shown above.
This arrangement allows us to use the 6m LNA in the housing with any of the 3-Element LFA antenna stacks or the 7-Element LFA antenna we are installing on this tower. One of the features of the microHam system is that it can understand and correctly sequence shared devices like LNAs, amplifiers, and other active RF components.
Preamp Housing LNA Control
The image above shows the configuration for the LNA control button that will appear on our SMDs. The configuration above creates a button and display to turn the LNA on or off when an associated button on one SMDs is pressed. This control will appear on the SMDs for any radio using one of the associated 6m antennas.
Preamp Housing Sequencer
We also need to configure a sequencing element for each of our 6m Preamp Housings. This ensures that the Push To Talk (PTT) lines and transceiver inhibit lines are properly sequenced for the transceivers, amplifiers, and relays in the Preamp Housing that is part of a path to a selected antenna. The microHam system automatically applies the appropriate timing and sequencing rules to all of the RF elements in the path based on the sequencer settings shown above. Configuring the sequencer also involved associating the appropriate relay control units on the newly installed Relay 6 Control Box with the elements in the sequencer timing diagram above. One item to note here is the 20 β 30 ms tail on the sequencing of the Preamp Housing relays when going from Transmit to Receive. This is done to allow extra time for any stored RF energy in the feedlines during high-power Tx to dissipate before bringing the LNA back into the feedline system.
We also added our second 6m Preamp Housing to the RF path for our existing 7-Element M2 Antenna on our VHF Tower and configured it similarly.
6m Antenna Stacks β microHam Virtual Rotator
The microHam system has a Virtual Rotator feature which is a great way to control selecting between fixed stacks of antennas of the type we are installing. The image above shows the Virtual Rotator we configured for our 3-Element LFA stacks. The Virtual Rotator becomes an additional antenna choice that accepts a direction in the same way that a conventional rotator does. The microHam system figures out which of the available stacks would best match any heading selected and automatically switches the antenna path to the stack that best matches the chosen heading. This capability will be a great tool in VHF contests when we are working multiplier grids on 6m.
microHam Control App β 7-Element LFA, shared LNA, and Rotator Controls
With all the configuration work done, I downloaded the final microHam program to all of our Control Boxes and SMDs and did some more testing. I connected one of our 6m Preamp Housings to the newly installed Relay 6 Control Box and tested the operation with our Transceivers. Everything worked as expected.
I also used the microHam Control App (shown above) to test the various combinations of 6m antenna selections and configured options. The image above shows the selection of the new 7-Element LFA we are adding. Note the availability of controls for the LNA in the shared Preamp Housing and the controls for pointing the antenna via the associated rotator.
Virtual Rotator for 6m Stacks
The image above shows the selections and controls for the 6m Antenna Stacks. The Virtual Rotator choice (STK-VR) is selected in this example. Each SMD has a control knob that can be turned to any heading. When the heading for the STK-VR antenna choice is changed, the system automatically chooses the stack that most closely matches the chosen direction. Choices are also available to choose any of the three stacks directly (ex. EU-STK for the LFA stack facing Europe).
microHam Control App β 6m Split Tx and Rx Antennas
Another nice feature of the microHam system is its ability to use different antennas for Transmit and Receive. The example above shows a setup that uses two different antennas for Tx and Tx.
As you can probably tell, the microHam Station Master Deluxe (SMD) system provides many features for controlling complex antenna arrangements and shared equipment. You can learn more about the microHam SMD system and what it can do here. You can learn more about the programming and operation of the SMD components via the SMD manual.
Weβll continue to post more articles in this series as our project proceeds. Here are some links to other articles in our series about our 6m Antenna Upgrade Project:
Our new LFA antennas and supporting equipment have arrived. The next step in our project will be assembling them and creating an adjustable mounting system for the 3-Element LFA antennas in our stacks.
Fred, AB1OC
The post 6m Antenna Upgrade Part 3 β microHam Antenna Control System appeared first on Our HAM Station.
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