Tuesday, September 19, 2017

Very simple 40m portable dipole with speaker wire.


Talking with Ross, VK1UN, the other day we stumbled on the simple idea of using figure 8 speaker wire as the feed line up to an "inverted V" dipole held up with a squid pole. Compared to feeding with coax up to a balun, this is extremely light weight and so doesn't bend the squid pole too much.

The video above takes you through how it works.

This is the antenna a plan to take to the next Sydney QRP by the harbour event coming up in October.

Handy lightning map

Brian, VK2AAF, just alerted me to a fantastic map of current lightning. LightningMaps.

Were were talking on 80m and there was quite a lot of noise but the weather here is fine. Turns out there's a lot of lighting off the coast towards New Zealand.


Very handy, thanks Brian.

Wednesday, September 13, 2017

Simple Fronius logger

If you can install python (which you can pretty much anywhere) here's a little script to get started with logging from Fronius inverter.

The latest source code is here.
import requests
import json
import datetime
import time

# Set this to the IP address of your inverter
host = "192.168.0.112"
# number of seconds between samples, set to zero to run once and exit
sample_seconds = 60 * 5


def main():
    print("started")
    while True:
        try:
            watts = watts_generated()
            now = time.strftime("%H:%M:%S")
            line = "%s\t%s\n" % (now, watts)
            # print(line)
            write_to_logfile(line)
        except requests.exceptions.ConnectTimeout:
            print("Connect timeout at %s" % time.strftime("%H:%M:%S"))
        if sample_seconds > 0:
            time.sleep(sample_seconds)
        else:
            return


def write_to_logfile(line):
    today = time.strftime("%Y_%m_%d")
    file_name = today + ".csv"
    out_file = open(file_name, "a")
    out_file.write(line)
    out_file.close()


def watts_generated():
    url = "http://" + host + "/solar_api/v1/GetInverterRealtimeData.cgi?Scope=System"
    r = requests.get(url, timeout=2)
    json_data = r.json()
    result = json_data["Body"]["Data"]["PAC"]["Values"]["1"]
    return result


if __name__ == "__main__":
    main()



Note that I'm assuming Python 3 and you'll probably need to install the requests module. The program outputs a single file for each day.

Here's some code to draw a pretty graph.
"""
Simple code to draw a graph of a day of power.
Requires matplotlib

On Fedora Linux: sudo dnf install python3-matplotlib

"""

import matplotlib
matplotlib.use('Agg')
import matplotlib.pyplot as plt
import matplotlib.dates as mdates
import csv
import time
import datetime

today = time.strftime("%Y_%m_%d")

INFILENAME = today + '.csv'


def main():
    data_reader = csv.reader(open(INFILENAME,'r'), delimiter='\t')
    y = []
    x = []
    for row in data_reader:
        if len(row) > 1:
            timeval = row[0]

            dt = datetime.datetime.strptime(timeval, "%H:%M:%S")
            print("timeval = %s -> %s" % (timeval, dt))
            x.append(mdates.date2num(dt))
            watts = float(row[1])
            y.append(watts)

    fig, ax = plt.subplots()
    ax.plot(x,y)
    ax.xaxis_date()
    my_fmt = mdates.DateFormatter('%H:%M')
    ax.xaxis.set_major_formatter(my_fmt)
    plt.ylabel("Watts")
    plt.xlabel("Time")
    plt.show()
    plt.savefig('%s_graph' % today)


if __name__ == "__main__":
    main()




Finding the IP address of your inverter is pretty easy if you have a network scanner such as nmap. I use LanScan on macOS and the Fronius comes up as having a network interface from "u-blox AG".

Saturday, September 09, 2017

Solar electric panels installed at home

The ham shed has been solar powered for many years. Finally it was time to install PV panels on the roof of the house.

The panels are installed on the west side of the roof as we already have solar hot water on the north side. Afternoon power might work well for running the air-conditioning on hot days.

Our last quarterly electricity bill was $447 and they say our average daily usage is 14.54kWh. (Yesterday the system produced 16.2kWh for the day, but much of it was excess).


We've put in 12 275W REC TwinPeak panels to give a theoretical total of 3.3kW. The house is three phase so we've gone with a Fronius three phase 3kW inverter.


The inverter sits next to the electrical switch box and there's a "smart" meter inside the box through which power to the house runs so it knows how much we're generating and how much we're using locally.


The Fronius connects to the home Wifi and pushes data up to a web site. For free it keeps three days of data and if you pay it keeps it longer. Here's how a full day without clouds looks:


The big lump of usage in the evening was me baking dinner. This is where a battery would obviously help.

Here's the highest power generation I've noticed so far:



I paid AU$6,201 for the system and given that we pay about $1,600 per year for electricity now, I'm hoping that it might pay for itself after about 5 years but this remains to be seen.

We currently pay about 24c per kWh but the feed in tariff is just 6c but on current figures there's quite a lot of spare power available to earn credits. After the next bill I intend to take the Prime Minister's advice and shop around to get a better price and better feed in tariff.

Already I've changed my behaviour in that I wait until sun falls on the panels from 9am before turning on the clothes and dish washing machines to take advantage of solar power. For breakfast I make coffee in a gas stovetop device.

A battery is an obvious enhancement but I'm not convinced that it would pay for itself any faster given the extra investment.

The German made Fronius inverter is an interesting device. As well as pushing data to their web site (or you can configure it to push to your own url) it has a group of web service APIs that produce JSON data. I have a simple project in mind to build a display of key data for the kitchen.

I think providing well documented open APIs in smart home devices is a key feature and I certainly chose to pay a little more to be connected. They have smart phone apps but oddly they have less information than the web site.

With a little hacking here's a little power generation display built with an ESP8266 and an OLED display.


HF radio interference?

I was concerned about this and chose not to go with panels that have built-in inverters. My tests so far show that the system does not produce noticeable HF interference when in operation. I have held a radio up to the inverter tuned off stations and can hear very little effect. Potentially having big diode panels on the roof might rectify HF transmissions but so far I haven't noticed any effects.

Monday, September 04, 2017

Door bench for the shed

A very simple, cheap, upgrade to my shed today. I've always struggled to build things on little folding tables. Today I paid AU$29 for a door and it makes a fine bench.


It's a hollow door so won't take much weight in the centre. I'm thinking of putting some sort of edge on it to stop things rolling off. I'll keep this next picture as a reminder of what it looked like originally.


The door is a narrow model. It's 2040x720x35mm. (I have no idea how many furlongs that is for you Americans).

Friday, August 18, 2017

Building wsjt-x 1.8rc1 on Fedora 26

The available binaries of wsjt-x don't run on Fedora 26. There's no problem building but it took a while to figure out the dependencies so this post is a note for myself that might help someone else.



From a fresh Fedora 26, here's the dependencies I needed to add before building.

sudo dnf install autoconf automake libtool libusb libusb-devel fftw-libs-single fftw-devel texinfo qt5 cmake asciidoc gcc-gfortran gcc-c++ qwt5-qt4 qwt qwt-qt5-devel qwt-qt5 qt5-qtmultimedia qt5-qtmultimedia-devel asciidoctor qt5-qtserialport qt5-qtserialport-devel

I stumbled around a bit figuring out what the missing thing was called in Fedora so there's undoubtedly things in that list that aren't actually needed.

At the end of the build I got an error linking -ludev so needed to do this to let ld find the library.

sudo ln -s /usr/lib64/libudev.so.1 /usr/lib64/libudev.so

(Let me know if there's a correct way to do this, I couldn't find a -devel package that should normally do this).

I basically follow the instructions directly from the excellent INSTALL document but I'm substituting the 1.8rc1 tag so I get the latest FT8 stuff.

cd ~
mkdir wsjtx-prefix
cd wsjtx-prefix

Download a snapshot from:
https://sourceforge.net/p/wsjt/wsjt/HEAD/tree/tags/wsjtx-1.8.0-rc1/

Unzip then rename:
mv wsjt-wsjt-8028-tags-wsjtx-1.8.0-rc1 src

From the file src/INSTALL, follow the instructions to download, build and install hamlib.

# As per the instructions in INSTALL
cd ~/wsjtx-prefix
mkdir build
cd build
cmake -D CMAKE_PREFIX_PATH=~/hamlib-prefix ../src
cmake --build .
sudo cmake --build . --target install

wsjtx 

Building is a good way to exercise your CPU.


Binaries?

I notice this site hopes to have binaries available but the builds seem to be failing. Does anyone know what I need to do to build wsjt-x as a static binary for easy distribution?

Sunday, August 13, 2017

Charging a laptop from 12V

Keen on portable QRP operation, I'd like to use digital modes which might require a laptop. While battery life is excellent with some models, I'd also like to be able to charge a laptop from my solar powered shed.

Recently I purchased some voltage buck modules which can step up a voltage to a settable output controlled with a multi-turn potentiometer.


There's lots of variations of these on ebay. This one takes an input of 3-35V DC and turns it in to an output of 2.2-30V DC with an output current of up to 1.5A.

I'm charging a little HP laptop which takes 19.5V so the converter is set to that and all boxed up nicely. (Except that I drilled the holes in the wrong places).


HP laptop chargers have three wires in the lead, positive, earth and ID. The ID wire (I learned thanks to commenter Brian G8OSN) needs to be pulled high for the laptop to charge the battery. I connected the middle ID wire to positive 19.5V via a 100K resister and that seems to do the trick.

On a related topic, I'm becoming a fan of 18650 Lithium Iron batteries, not just for super bright torches and Tecsun radios, but also for powering QRP gear if powered from a set of three 3.7V cells in a little case available for under $2.



These cells can be harvested from old laptop battery packs. Often when they die it's because one cell has gone bad and the others can be re-used. They don't make it easy to get them out though.


This pack from an old Asus netbook has three rows of two cells in parallel. These cells have a huge capacity compared to an AA rechargeable which might be 1,200mAHr, they are often 5,000mAHr or more. Here they are in the fancy new charger that's just arrived.


I see that this month's Silicon Chip has an article about these cells.

Monday, July 31, 2017

Meetup with Peter VK3YE

Peter, VK3YE, was in Sydney briefly and a few of us had the pleasure of meeting up before he braved the enhanced airport security. Stephen, VK2BLQ, brought along his beautiful valve regenerative radio.


John, VK2ASU, made the journey from Maitland and brought a few interesting projects for inspection including a Tuna Tin radio.


After Peter left we had a duel between John's regenerative 80 receiver and a Tecsun PL-880.


Thanks Peter for popping by. Catch you on the air by the bay or the harbour!

After lunch, John and I walked around Chatswood inspecting cameras, telescopes, 3d printers and torches. After becoming familiar with the prices out of China on Banggood and AliExpress it's hard to take the retail prices of many of these products.

Lubuntu Linux for low power, low memory computers

I like the little HP Stream 11 laptop but Ubuntu is a bit slow on it so I've recently installed Lubuntu Linux. Based on Ubuntu but with a lighter weight desktop and windowing environment it runs well and does not use the 2GB of RAM available in this machine.


Even with the Chromium browser running there is free memory available.

To find out more detail about where your battery power is going, there's a utility that can be installed with apt, called powertop.


Amazing to see an Intel laptop consuming 3.55W.

There are a bunch of tunable settings that can be adjusted in Linux to get better battery life, mainly turning on some power management settings, I've turned on each of these and so far so good.

While Lubuntu is fine, I do miss a few things from full Ubuntu such as the ability to search for an app to run it, also the window edges are very narrow and rather hard to grab with the mouse.

I've noticed that some operations, such as 'apt update' hang for 120 seconds before starting. At first I thought this was a DNS issue but it turns out that disabling ipv6 fixes this for me. (Obviously, I would prefer to use ipv6 but perhaps my ISP or home network isn't quite up to it).

All in all, worth a try on a low end laptop.

Monday, July 24, 2017

Tecsun PL-880 mini review

There was a time when Sony ruled my portable short wave listening world. In recent years Tecsun has brought out a series of decent radios suitable for packing on trips.

This week I popped in to Av-Comm nearby in Brookvale, local distributor of Tecsun and purchased a PL-880 from them. (They're not really set up for walk-in customers but very friendly none the less).

The PL-880 is powered by a single high capacity Lithium 18650 battery which is charged inside the radio using a mini-USB socket on the side. Av-Comm supplies a suitable cable and plug pack but it's likely you already have one lying around.

These 18650 cells are turning up everywhere these days, in high brightness torches, even in home made power walls, and they seem like a worthy successor to the ubiquitous AA cells. Being 3.7V they can power lots of devices with just one cell.

The radio comes in a very nice faux leather zip around case that includes a log book. There's a large world map poster with ham radio prefixes marked on the countries and Av-Comm includes a guide to short wave listening.

Audio is excellent, probably the best I've heard in a portable radio. AM and FM sound terrific. There is a "bass" or "treble" switch that I've left in treble position but there's still a warm sound there.

On shortwave, sensitivity seems excellent. Here's a bit of Radio New Zealand International using just the whip antenna inside the house.


During this video I switch the DSP bandwidth a few times but I think this is a pretty narrow transmission.

The radio also has proper upper and lower sideband. Here's a recording of a 40m LSB conversation again just using the whip antenna.


You can hear that the tuning, although digital, is silky smooth. This is where this radio shines, previous models from Tecsun and others have not tuned well - making a chop chop sound - but this radio slides smoothly and the separate course and fine tuning knobs work well particularly if you're interested in sideband.

There's a switch for the display light that if you turn it on keeps the display lit even when the radio is turned off. Normal mode is to light up when you touch a control and then turn off again after a few seconds.

I found that the radio shows some signs of being overloaded when on the most sensitive position, various spurious signals can be heard that go away with the attenuator switched to the first position.

In all a great radio with controls familiar to you if you've ever had a previous Tecsun radio. My favourite feature is the sleep timer that turns it off after a settable period of time at night. High sensitivity, lovely smooth tuning, passable sideband and big clean sound that can fill the room. Recommended. AU$249.

Saturday, July 22, 2017

Amazon Lightsail doesn't have virtual memory

My cloud hosting needs are modest. A couple of Wordpress blogs, an OpenVPN server, and a Tiny tiny RSS server. I use Amazon’s AWS services for S3 storage for miscellaneous files and backups using ARQ. When Amazon launched Lightsail with a VPS starting at just $5 a month (for 512MB RAM and 20GB SSD), I moved over from Linode where I was paying double that.

All seemed good at first, Amazon’s infrastructure gave me better ping times than others, but I noticed that mysql was going away from time to time. Tailing the system log I could see kernel out of memory messages and that it was killing mysqld. You see entries saying "OOM". The kernel kills the process that's using the most memory which tends to be mysqld.

My first thought was to increase the RAM but there’s no simple way to do this on Lightsail, you must take a snapshot (backup), make a new instance with the new memory and build it from the snapshot. When all is up the external static address is simply re-pointed to the new instance and the old instance can be stopped. This isn’t at all difficult but it seems like something computer software should do.

After upgrading the RAM it dawned on me why Linux was running out of RAM - Lightsail instances have no virtual memory! It turns out there’s no easy way to add a swap partition and they actually warn that if you did it would be too slow.

Paying $10 a month for a Lightsail instance with zero virtual memory becomes uncompetitive with my old favourite Linode who offer 1GB RAM and 30GB SSD including VM for the same price.

So, I’m back on Linode and frankly happy to be there. Amazon is a gorilla in the hosting game but their offering is incredibly complex and, it turns out, has some little gaps.

I realise my home use is at the very low end but, as the song says, “from little things, big things grow”.

Not having any virtual memory is a major problem for any real server.

Update: another low cost VPS provider: Vultr

Vultr is a new provider of virtual machines that starts (at the time of writing) at US$2.50 per month for 1CPU, 512MB memory, 20GB SSD and 500GB of bandwidth.
A suggestion from John.

Bandwidth is charged at the maximum of incoming and outgoing. Excess bandwidth is charged at 1 to 5 cents per GB (depending on where). You continue to be charged for a stopped instance - you must "destroy" it to stop being billed.

OS options are CentOS, CoreOS, Debian, Fedora, FreeBSD, OpenBSD, Ubuntu, Windows or upload your own.

They claim to be faster than competition from AWS and Rackspace and given that I'm in Sydney and they have a location here, I'm going to give them a shot.

Accounts must be topped up before use, so I guess this is pre-pay, but once a first payment has been made they take Bitcoin which is handy.

Hmm, bait and switch eh? It turns out that once you pay them some money, the US$2.50 server size is "sold out" in Sydney... not impressed. By default the Ubuntu image has no swap, like Lightsail, but they have a guide to manually adding a swap file.

Friday, July 21, 2017

New weak signal mode FT8

Although it sounds disturbingly like a new rig from Yaesu, FT8 is actually a weak signal QSO mode from K1JT, Joe Taylor, and the folks who gave us WSPR and other modes. The mode is Franke-Taylor design, 8-FSK modulation.

I've just had my first contact with Steve VK6IR who is located right across this wide brown land.


I saw his CQ, received at -4dB, double clicked the line and the rest of the QSO, including signal reports each way, was automated.

Unlike WSPR where each over takes two minutes, the cycle time in FT8 is just 15 seconds so it feels a lot more like you're actually having some sort of conversation.

This new mode is in the latest builds of WSJT-X, version 1.8.0-rc1 in my case.

The release notes describe FT8 as follows:

"New mode called FT8: sensitivity down to -20 dB on the AWGN channel; QSOs 4 times faster than JT65 or JT9; auto-sequencing includes an option to respond automatically to first decoded reply to your CQ."

AWGN is Additive white Gaussian noise, obviously.

I kind of wish this was all a little bit more manual and that I could have a few more characters to personalise the QSO. Maybe we need a Twitter like digital mode?

Tuesday, July 11, 2017

Participating in GovHack

It's GovHack time again! This year it will be held over the weekend from Friday 28th to Sunday 30th July 2017. Back in 2015 I joined a team called "Hackasaurus Rex" with daughter Cat and her boss Ben and we participated at the Canberra location.

Ben brought graphic design skills, Cat did data analysis and transformation (in python) and I did iOS development.

On Friday night we looked at the amazing array of data available and came up with the idea of making an app that lets you check a place to live to see how... "liveable" it is.


The effort involved grabbing data from a variety of sources, normalising that data into scores that indicated the "goodness" of a location. Some data sets used postcodes and others used suburb names so there was some work required to map these.

While it was freezing cold in Canberra, the atmosphere in the room was warm and focussed.


I think having a small team worked well for us and the fact that our skills were all different and yet complementary meant there wasn't much overlap. Our entry suited the iterative development style that a hackathon invites in that we had something working pretty early on Saturday and were then able to add more data until we figured it was time to write up what we'd done and make the video you need to enter:


Making the video does take time and our approach was to make a recording of the mobile device screen first and then record a description which was added as the audio track later. Some teams did things as simple as making a slide show and exporting it as a movie while others made full on documentaries about their entry.

GovHack is a wonderful event, it encourages diverse teams to come together to work with fantastic data from enlightened government departments. The sponsors that get behind it are to be applauded and the organisers do a great job. This year I'm a volunteer and will be hanging out at the Sydney event.

If you're reading this before 28th July, get over to govhack.org to find out more and register. I look forward to seeing you there!

Monday, June 19, 2017

Lo-Key features QRP by the harbour

Thanks Lo-Key for featuring QRP by the harbour on the cover and in a feature article. It's a great newsletter of general interest beyond just CW operators. More info at http://www.vkqrpclub.org

Thanks to editor Terry, VK2KTJ, for promoting the event and giving us this coverage in such an auspicious journal. I encourage readers to subscribe via this page.

Future of Radio Australia Shortwave broadcasting - Senate Committee Hearings begin

Last Friday the Senate Committee hearings into a bill by Senator Xenophon to compel the ABC to resume short wave broadcasting began.

The SWLing Post reports that former RA transmission manager Nigel Holmes appeared. He jovially described being "grilled like a breakfast kipper" but I'm confident his encyclopaedic knowledge would have served the committee well.

I think it's important that there is a discussion about the value of short wave broadcasting at this time,  there have been many interesting submissions, in my submission I argue that it's not the archaic technology as it has been presented and in times of conflict or natural disaster it's the only thing that gets through.

Geoff Heriot has written that abandoning shortwave is just one more step in the winding down of Australia's engagement in the Pacific. Graeme Dobell describes the end of our shortwave service as "technical bastardly".

The inquiry has been granted an extension of time and will report on 9th August 2017.

Sunday, June 18, 2017

Switched to the NBN - seems good

We've been receiving letters for months from ISPs offering to be the ones to connect us to the NBN which has just arrived in our area.

As we were already on Telstra cable we decided to switch with them. I chose to self install the modem and a router arrived a week ago. It was puzzling because it didn't have a cable connection on the back.

Today the missing piece, the black box shown at right, appeared and it connects to the cable and to the router.

The router is a white box titled "F@st 5355TLS" made by Sagemcom Broadband SAS, not a company I was previously aware of. It seems like a competent device with 2.4GHz and 5GHz radios, two ethernet ports (not counting the WAN port), USB file sharing, and a telephone line port which we don't plan to use.


In the past I had put the Netgear modem into bridge mode and used a TP-Link wireless router which served us well and I may well switch to that again if the Sagemcom box proves unreliable. So far all seems good and the measured speed is more than I was expecting (I'm paying for 50Mbps down and 20Mbps up).


Ping time is better than reported there, normally around 10-12ms. I'm not clear if the Sagemcom box is actually needed given that I have other routers here I'm happy with.

I had a few problems getting ethernet connected devices going, in the end connecting them one by one did the trick, there was some sort of network storm going on possibly triggered by the change in IP address range.

It's weird that when switching to the NBN you are compelled to get a landline phone - something we have not had for some years. Here's the bit of the signup form that forces you to get a phone:


I tried putting my mobile phone in there but it wouldn't let me. (Probably a bad idea anyhow). A few more tests tonight:



Update - first problems

Tonight I started to see high ping losses. This is from the router:

 Pinging 8.8.8.8 with 64 bytes of data:

 Reply from 8.8.8.8:  bytes=64  time=7  TTL=59  seq=1
 Reply from 8.8.8.8:  bytes=64  time=9  TTL=59  seq=2
 Reply from 8.8.8.8:  bytes=64  time=8  TTL=59  seq=3
 Reply from 8.8.8.8:  bytes=64  time=7  TTL=59  seq=4
 Request timed out.
 Reply from 8.8.8.8:  bytes=64  time=7  TTL=59  seq=6
 Reply from 8.8.8.8:  bytes=64  time=8  TTL=59  seq=7
 Reply from 8.8.8.8:  bytes=64  time=9  TTL=59  seq=8
 Request timed out.
 Reply from 8.8.8.8:  bytes=64  time=8  TTL=59  seq=10

 Ping statistics for 8.8.8.8
  Packets: Sent = 10, Received = 8, Lost = 2 (20% loss),
 Approximate round trip times in milliseconds:
  Minimum = 7, Maximum = 9, Average = 7

Telstra's service status shows no known issues, but I'm not sure if that is relevant any more.  Rebooted the router, no change. Rebooted the NBN cable interface box fixed it.

Now ping from my computer on the network looks pretty good:


Friday, June 02, 2017

Good value laptop for linux - not what you might expect


There are very low cost laptops around but they're often unsatisfying in the end. The family is down one Mac laptop at the moment due to a fault in the keyboard and I had a look at what's available second hand.

Generally Apple gear holds its price very well, which is great if you want to sell to upgrade but not so good of you want to get a cheap Mac.

There is a regular trickle of Mid 2012 MacBook Pros appearing on eBay. This model is the last one before they went retina.

With a 2.5GHz i5 CPU, they are built like a tank but are very easy to open and work on. Some people even say "The 2012 Non-Retina MacBook Pro Is Still the Best Laptop Apple Sells" and while that's not really the case if you value a high resolution screen and light weight, they are attractive at the right price.


I was pretty lucky and got one for AU$415. The battery wasn't great, a few key caps had been substituted, it had 4GB of ram and a slow spinning 500GB disk. Otherwise it's fine.

A few standard cross head screws aside and you're in and able to upgrade the machine.


As it came, and as they were at the time, the machine felt pretty slow. I added the following enhancements:

  • 120GB SSD
  • Extra 4GB RAM to take it to the maximum of 8GB
  • New battery
The SSD makes a huge difference and if you are still running a spinning disk I can't recommend this upgrade enough. Four or five bounces to launch Safari is now just one.

These machines will run the latest edition of macOS, Sierra, and support AirDrop and Handoff.

A non-retina screen is a shock after getting used to it on every other device I look at. Apple's switch to the San Francisco font actually makes a non-retina screen look worse. There is a utility to switch the system font back but I found the font metrics are so wrong that you see lots of glitches running like that so I don't recommend it.

Linux

It turns out that dual booting Linux on a Mac does not require Boot Camp or any of those fancy EFI boot tricks.

To install boot into the recovery system by holding Command-R during power on and use Disk Utility to resize the main partition down to leave free space for Linux. Hold option during power up to boot from a Linux USB install drive.

Fedora Linux was installed into the free space on the disk. To choose which OS to boot into you simply hold the Option key down during power on and you get this nice menu.


Wifi doesn't immediately work after a clean linux install due to proprietary drivers but happily this machine has an ethernet port and I simply followed this recipe to get the driver installed and now Wifi works well. 

Everything else just works including volume, screen brightness keys and sleep on close.


It makes a very respectable Linux laptop. One thing to note that after the install you should boot into macOS and set the startup disk in System Settings so that by default it will boot into macOS (if that's what you want).

Saturday, May 20, 2017

YouKits SK-1A QRP 40m transceiver review

YouKits is getting a good reputation for low cost amateur radio gear. Their antenna analyser is well regarded. When I saw a new mono-band 40m SSB / CW transceiver for US$189 including postage I couldn't resist. It's called an SK-1A.

It arrived very quickly and was easy to figure out even without reading the user manual.

While it comes with a Yaesu branded speaker / microphone, it's not wired to use the speaker in it so you must use headphones or an external speaker. Note that this transceiver does not have a built-in speaker which probably isn't a bad thing given the small size of the case.


I've had two contacts so far, one local and another VK2 to VK3. Both reported good audio from me and I found reception at my end pretty good. Disconnecting the antenna shows that the receiver is sensitive enough to hear band noise which is all you need on 40m.

The display is clear and the backlight is bright. The manual includes instructions for adjusting the display but it's not brightness or contrast, it lets you switch the backlight on, off, or auto.

Internally, construction seems good with lots of surface mount components used throughout. There's no circuit diagram in the manual, which is a pity, but you can see that the 6 crystal IF is on 4.9152Mhz and there are a few SA602A balanced mixers in there along with an LM386 audio amplifier.


The VFO board behind the front panel is compact and the software works well although I find the way pushes on the knob change between going up and down in step size a little weird. The soldering on the PIC microprocessor looks a little rough on my unit but all seems to work reliably.


The final is an IRF510 and I get about 4W peak output. I like the way they use shielded coils.


Main board soldering is good but clearly done by hand rather than machine.


Internally there's a socket for the 18650 Lithium battery pack which they supply with a charger but it looks like you'd need to open the case to charge the battery.

This radio is lower sideband only (along with CW), which is perfectly fine for voice contacts but I was rather hoping to use it for digital modes which normally need USB.

While a traditional SA602 based design, this radio works well enough and is more compact than even an FT-817. 40m is a good choice for a mono band QRP radio. There's no deafening thump during receive / transmit switching like I get on some other designs and audio output is more than enough for headphones but a little low for an external speaker.