Adding Load to Solar Power.

For the winter the old load on my shack solar power system has been just the IC705.

The nice thing about the IC705 is the band coverage. All bands between 160m and 70cm, with the exception of 4m. Then there is the spectrum scope. That is a great feature. Third, the power consumption is only 300mA at receive. I am considering getting one more, but as the more advanced HF stations draw much more power, just receiving:

FT817: 400mA

IC703: 600mA

IC7300: more than 1A

IC7600: even more power than the 7300.

IC7100: I think it is below 1A, maybe about 800mA

In winter time with the current solar power system those on the list above cannot be run on solar power.

Today I made the beginning of a small  low power system:

Using a pair of computer speakers I connected the speakers to my 4-band CW QRP transceiver, the HB-1B, drawing only about 80mA capable of running 20, 30, 40 and 80m. The HB-1B only has a headphone output jack, so more audio power is needed for speaker volume. The HB1B does have a variable bandwidth crystal filer, and can be used for both SSB and narrow bandwidth CW reception without additional filtering. The system works nicely. Later the computer speakers may be replaced by a separate audio amplifier box (with additional circuitry) built into a single box. 

I intend to expand the system with more transceivers, and later some switchable filtering:

Split the inputs, so that one SSB/CW receiver goes in one audio channel and one more in the other. A third one can be added with the output evenly split between both inputs, creating a "centre channel".  One of those receivers could be the old PM2B set up for 20,40 or 80m reception. A repair/modification will be necessary for the 80m preselector, but that should not be too tricky. The PM2B is also very convenient to add to the monitor system, as the power consumption is only 20mA, easily added to the current solar power system.

This means that 3 different signals can be distinguished. Since these signals have a noise floor, the idea is to add 3 FM receivers in parallel, making the signals from 6 receivers distinguishable/audible via the 2 channel audio system. This requires a simple mixer system that I can construct without too much difficulty, making the monitoring of 6 different frequencies possible, as the FM receivers will be squelched, and therefore distinct from the SSB/CW audio.

Later some audio filters, and maybe equalizers and input switches can be added to this system. 

AR8600 Filters and Add-on.

As mentioned earlier, the AR8600 receiver originally has a poor SSB filter. 

I do have an old Mk1 and a newer Mk2, and the filters are different. Also, the Mk1 stops at 2040MHz, and the Mk2 continues up to 3GHz, so it is useful for reception on 2400MHz, too. 

I suspect that a preamplifier will be needed for those high frequencies. I can find one, or use a module I have for that.

I made a search on Ebay after looking at a video on updating the receiver.

I did locate one SSB filter suitable filter, and ordered it from Japan. This is an 8-pole Collins SSB filter that should be much better that the original Murata filter in the receiver. The post mentions the AR8600, so I hope that the filter fits in the PCB. I am hoping to receive the filter some time in February.

The filter I ordered looks like a fit for the Mk2, and that suits me fine, as the Mk2 has the wider frequency range.

I suspect that I will have to find an alignment procedure for the AR8600s, as there seems to be some misalignment, at least in the Mk1 I have used until now.

I do have an AR7030, too, and I also ordered a 500Hz CW filter suitable for that one.

When I look into my crystal ball I see some upgrade activity in my future ;)

An added Idea Box entry:

The other part is the audio output of the AR8600. The built-in speaker is very small and not very loud. So I am thinking (ouch! ;) ) of building myself a new audio device with an external audio amplifier, possibly with an equalizer circuit (I have PCB a module for that), and an audio CW filter.

I do have a stereo amplifier suitable for use with at least two radios. With a little mixing trickery that could easily become 3 radios simultaneously, one in the left channel one in the right, and the last one in the middle. With an external switch box (that I already have) more radios could be added to the external audio system, albeit not all radios simultaneously.