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Apollo is to be a companion 15W PA and Low Pass Filter for Hermes. The idea is to build a self contained HPSDR Transceiver into a box similar to the one used for the two Alex boards.

The box, made by Hammond has a sliding cover on one of the sides (Series 1455, PN 1455N1601). This cover can be used as Front Panel and behind this a display up to 4 inches may be installed. There will also be space for a controller (Beagleboard or something else). One of the goals is a small platform to use as controllers for a self contained transceiver.

Another goal is current consumption of less than 0,3- 0,4 A but this seems to be difficult with the existing units (Ozy, Mercury and PC/ controller). If we can manage to get all into this box and working with suitable software, we can modify the hardware and use less power hungry components for a 2.nd generation transceiver.

Using latched relays for filter switching will save power. This will require modified software but should not be difficult. The interface to Hermes will be I2C.

The LP Filters will be based on Alex but with only one Antenna connector. The toroids may be smaller (T38 instead of T50). Also the capacitors can have lower voltage ratings. An Antenna Tuner can also sit in on the same board. (LDG makes good tuners so it may be possible to use one from them)

October 10, 2009:

Today I posted a new version of the schematic and PCB layout of Apollo and ATU (Apollo - Development Discussion).

I have included an ATU on the 100X160 Eurocard. For this, we use an ATMEL CPU, AT90USB1286-16AU. The ATU has 8 Toroid wound coils and 8 Mica capacitors controlled by 17 latched relays for low current consumption. The CPU can be programmed via JTAG, USB and also I2C from Hermes. Software for the ATU will be created by LA7DJA, Espen.

In cooperation with Kevin and Tony, I have included the possibility to interconnect Hermes and Apollo internal in the cabinet. The Apollo may be used for connection to other TX/RX units.(SDR or conventional)

I am in the final stage of the PCB layout. The PCB had to be 4-layer. The complexity and compact size prohibited the use of only 2-layers. The stability of the circuits are highly improved with one layer with a continuous Groundplane.

Comments and suggestions are still possible, but I hope to send the Gerber files to the manufacturer during the next week.

73, Kjell

See Also