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Tuesday, 28 November 2017

hands-free mic installation and hearing the ISS

This evening, in light of it being delivered to my work QTH this morning, I fitted the hands free microphone into the car, I have not received any on air reports from it however so I don't know how well it is working and if I need to adjust the mic gain (a trimpot marked "vol" on the side of the switch box), the switch is fitted round the gear stick, and the microphone itself is fitted to the sun visor.

On the downside the channel up/down controls don't work on the Yaesu FTM-400, they simply send a 4 and 7 respectively, so this means I have to use the control panel to change frequency, though this should not be a difficult task as I've reconfigured the radio to allow me access to an on-screen keypad, I don't know if this sends DTMF or not, I'd need to test this out or refer to the manual.

With the switch on the gear stick it means I need to use care in not flicking the switch unintentionally and informing any passengers I have that they are not to touch it, though with it being on the gear stick they probably won't anyway.

A convenience feature of this microphone is that it has a 2.5 minute alarm, so I know if I have been talking too long, as can happen, though I tend to keep my overs short if possible.

While I was finishing tests, I took a test drive amongst other things to ensure the fittings were sound, I tried to call on the digital voice calling frequency, no one was there, and given the order it is stored in my FTM-400 I managed to catch on to what I initially thought was noise on the ISS 2-metre downlink frequency only to find a QSO ongoing between one of the astronauts (IZ0JPA as I later discovered) and a ground station, a school in Ontario, Canada (I did some digging around to see if there were scheduled contacts), I recorded a small part of the QSO on my phone (of the ISS side from IZ0JPA as that was audible, the Canadian side would not be for obvious reasons) but I do not intend to upload this to YouTube as it was spur of the moment and not on par for a YouTube video

The reception of the ISS was unexpected, and it must have been within range for a time, not bad for a vertical antenna on the roof of the car, in fact I would have happily kept listening had I had time and it wasn't nearly freezing out.

As for the hands-free microphone, I hope to get some audio reports on that in the next few days.

73 de 2E0EIJ

Sunday, 26 November 2017

Hands-free mic for radios

You may remember that I wanted to get a hands-free microphone for my Yaesu FTM-400XDE from Martin Lynch & Sons while at the National Hamfest this year, only to discover they had none with them as last year no one bought them, so I have ordered one, at last, off their website with wiring for the Yaesu radios that have the same mic socket as mine, my plan is that as I have booked Friday afternoon off work is that I can begin fitting it to my car and perhaps tidy up the control head cable as well as the cable tie mounts that hold that on had come off during the summer months when the temperature inside the car reached high levels enough to soften the adhesive on the cable tie mounts, important considering the cable is starting to foul the passenger side airbag which could prove dangerous if I have a crash with a front seat passenger on board.

The microphone mounts to the hinge of the sun visor with a cable running to a control box that mounts to the gear stick (though this does not work in automatic cars very well), it has a toggle switch for PTT and up/down buttons (which do not work with the FTM-400), and should time out after 3 minutes TX should it be left on by mistake, this means I don't have to hold a microphone and only have to take my hand off the wheel to key up and again when I have finished speaking to go back to RX.

This would also leave me without direct DTMF entry unless that can be done from the control panel, I'd need to read the manual to find out if this is possible, alternatively I could find a way to keep both mics plugged into the radio and allow a way to switch between them.

Though I do like to operate mobile, the majority of the roads around here don't lend themselves to the mobile operator due to lots of bends and roundabouts, and I consider road safety to be priority number one when driving, if I cannot drive and operate my radio safely I won't operate the radio at all.

On a side note, I should have been attending this year's Bishop Auckland rally at Spennymoor, however it is early this year (today) and I have not been paid, so it looks like the next rally I will be at will be either Ripon or Blackpool next year, whichever comes first.

73 de 2E0EIJ

Sunday, 12 November 2017

Noise levels

I took a drive out to the village of Hudswell today to do some noise checks, though as I was using my RTL-SDR (the NooElec one not the cheap one) I obviously was unable to check below 24MHz, however my findings are good, and the noise levels at the location are pretty decent, though for a true reading I need access to HF gear that can cover below 24MHz, the local club have such equipment and members of the club went up yesterday.

The antenna in use was one of the NooElec supplied ones on the supplied magmount, through an open window on the car, I mostly checked amateur bands, particularly 10-metres as it is the only HF band I can get on my existing equipment, for below this I'd need equipment for it which as you know I am saving for.

I will follow this up in due course.

73 de 2E0EIJ

Sunday, 5 November 2017

433.92MHz Energy monitor transmission monitoring and possible reverse engineering

On trying to find out exactly what my energy monitor device is transmitting, as I know it to operate on 433.92MHz I find this part of the band filled with transmissions, this is due to the vast array of licence free devices used here, particularly remote car keys as these are by far the most common of them all, this of course makes it harder for me to figure out what my energy monitor's transmitter is doing, though the only device making sense of the signals from the sender by the electricity meter is in fact the display for the energy monitor itself.

In order to do this I have connected an SDR to my laptop, my NESDR SMArt rather than my basic RTL-SDR as this would not have done a good job and currently I have no way of putting my antennas onto the basic one, and it is prone to drift and interference, whereas the NESDR SMArt is not as it's very well engineered, software side is SDR# as usual as it is my preferred choice, antenna is the shortest one that came with the NESDR SMArt as it seems to be the most effective, after some playing about the mode to receive all this appears to be AM, not FM as I initially thought.

The energy monitor is a cheap one I bought from the local Poundstretcher shortly after moving into the previous QTH, though it is based on an old design Efergy unit circa 2009 (possibly earlier) I see no information on what corresponding Efergy model number it is nor any means to reverse engineer the RF side to receive it and decode the data for putting into a graph or chart which the newer Efergy devices can do anyway with a simple add-on, though why buy it when you can build it yourself, I'm a tinkerer and radio Amateur, so why not play about with it, after all I do like taking stuff to bits, and no big loss if I break it as I can simply replace it with a newer Efergy unit.

Having not removed the covers from either side of the monitor, it appears to be a standard 433MHz TX/RX pair from photos I have seen online, the TX side has an unpopulated header on the main board (serial port maybe?) and so does the RX side (again, possibly a serial port), I've not got as far as finding any further information on what I should see on the SDR# waterfall nor have I figured how it transmits the data, aside from using, presumably, ASK which explains why I have to look at 433.92 in AM.

If I can figure this out it would be great, then I can hopefully extract the data and make it something that can be comprehended and put into a web-based graph or chart, all I need to do that is a 433 receiver, and a means to decode the data in the transmitted packets (Raspberry Pi would do a sterling job here and can run off a battery that can be recharged so it will read 0 in the event of a power outage), and then I'd be able to access my usage data from anywhere in the world

Let's see what comes of this then.

73 de 2E0EIJ

Update: 17:48

I have finally figured out how to get my energy monitor open and have done so, however all was not as expected

The CPU is in the centre as per the Efergy units however it appears that it is not the same device, the receiver is of a different type to the Efergy units as well, the unpopulated header is labelled differently and presents no real way to fit headers as a mounting screw fouls it, finding the embedded data in the radio signal from the transmitter will require some further work than I initially thought, if not I can simply buy a newer Efergy device and transfer this project to that as these are more common, though that would have to wait until payday methinks given I had to fork out for car parts and fitting last payday.