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.

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.

Wednesday, May 10, 2017

Radio Australia's Shepparton broadcasting site for sale

For the ham who has everything... a lovely 500 acre vacant site at Shepparton, Victoria, Australia complete with short wave antennas (I assume).

More details here.

They say it's a significant "land banking" opportunity, whatever that is.

Close to a highly regarded school and just "moments" from the Shepparton Town centre.

But seriously, the site is up for sale while there is a pending bill before the senate calling for the restoring of shortwave radio.

There have been 40 submissions received (including one from your humble blogger). The inquiry is due to report on 9th August 2017.

Lovely cabinet work on site:


I'm advised that the property will be sold with buildings only, antennas and feed lines above ground will be removed.

The local Shepparton News is reporting that not everyone is happy with the shut down of the shortwave service.

Sunday, April 23, 2017

rtl-sdr direct sampling on linux

There's a nicely put together rtf-sdr receiver box available on Ebay from China for about AU$45 with the direct sampling modification for HF already done for you and separate inputs for HF and VHF+.

There are several sellers so shop around.

You can see it on the right here and the box above it. (Click to enlarge)

Internally, it's an RTL2832U.

On my recent weekend visit to Kevin, VK2KB, I helped to get it going under Windows using SDR# software and this prompted me to get mine going at home under Fedora linux.

One mistake I've made before is that some USB cables seem to come wired only for charging and don't wire up the other USB connections. I wasn't seeing the device in lsusb and when I tailed the log (which, incidentally, has changed under Fedora since I last looked, to be sudo journalctl -f), there was no chatter as the device was plugged in. Trying alternate cables fixed this.

It turns out that GQRX finds the device just fine. To switch on direct sampling from the Q input, you set it like this:


CubicSDR saw the device but couldn't receive until I blacklisted the built-in TV reception driver by creating a file /etc/modprobe.d/blacklist.conf and entering blacklist dab_usb_rtl28xxu in it. Then I rebooted.

After that, the CubicSDR device config looks like this:


And it receives 40m SSB like this:


(There's not much on at this time of day).

Google reader alternative - tt-rss review

I still miss Google Reader which went away in 2013. It was an efficient way to catch up on all the RSS/Atom news feeds I subscribe to in a web browser.

The key feature I need is that whatever I use remembers what I've read and can be accessed from multiple devices that stay in sync.

When Reader went away I subscribed to FeedWrangler which works well but lacks a decent web interface so must be accessed from a macOS or iOS app such as Reeder.

Recently I've installed Tiny Tiny RSS, also known as tt-rss on a Fedora linux computer in my home network. The installation guide is good but I ran into a few things that were not right on Fedora 25.

I chose to use mariaDB (mysql clone) as the database although they recommend Postgresql.

From memory, the issues I encountered were:

  • PHP couldn't connect to the database due to secure linux. 
  • httpd couldn't write to the tt-rss web directory for config and cache writing. Needed # setsebool -P httpd_unified on
  • The name of the mysql driver for php is different, I needed # dnf install php-mysqlnd
  • # dnf install php-pdo php-gd php-mbstring php-common php-apc
To get my feeds imported, I exported the OPML file from FeedWrangler and imported it into tt-rss by going to Actions, Preferences, Feeds tab and there's a long horizontal panel called OPML that's a button for choosing the file to import.

The user interface is nice and clean and I particularly like how it responds to up and down arrow keys to roll through the stories in the scrolling panel.

Updating feeds


The authors suggest leaving a process running to do the updates (it sleeps periodically) but I prefer a cron job as follows:

*/30 * * * * /usr/bin/php /var/www/html/tt-rss/update.php --feeds --quiet

Anyway, so far I like it a lot and my plan is to eventually move it to a virtual server in the cloud. It looks like you can aggregate all of your unread items into a new feed and presumably read that from an app while out - this could possibly replace the commercial service I'm using at the moment.

Friday, April 14, 2017

QRPver pocket sized transceiver review

The QRPver is a US$80 1W QRP transceiver that is perfect for running digital modes such as PSK31. It connects to a computer via analog audio cables and has internal VOX so there's no need for an interface box or serial rig control.

It's about the size of a pack of cards as you can see in the photo on the right. 

I'm using it with Fldigi running on Fedora with a generic USB audio dongle. I did need to use the Sound application to increase the audio level a bit to get the VOX to trigger when I transmitted.

Note that the audio sockets are stereo sockets with left and right tied together so you do need to use stereo leads or you'll short audio to ground.

I ordered my QRPver for 14.070 (there are a range of bands and frequencies to choose from). 20m PSK31 was very lively a few years ago but at the moment seems rather abandoned for some reason, perhaps everyone's running JT65?

First contact was pre-arranged with Stephen, VK2BLQ who is pretty near by. Today VK5WOW popped up being operated by Grant, VK5GR who made a few comments about the signal not being all that clean and also it drifted about 20-50Hz during a longer over.


The QRPver draws just 20mA on receive and 650mA or so on transmit so it would be great for portable digital operation. The receiver seems sensitive enough and while not a perfect signal on transmit - something that might be because I need to tweak the level a bit or possibly there's some RF getting in to the audio - I think it's a great gadget for the travelling ham.

Tuesday, April 11, 2017

Switching from Ubuntu to Fedora Linux

Ubuntu has been great for me over about the last ten years. Prior to that I was a RedHat/Fedora user but when I joined a company that was all Debian based I made the switch and learned the joy of apt.

Recently I've run in to some hitches with Ubuntu. It throws up crash handlers from time to time. The ham radio applications offered in the official archives are often very old and recently I found that gnuradio installed with apt runs but crashes in use. (Building from source fixed this).

The announcement that Ubuntu is abandoning the Unity desktop and switching to Gnome prompted me to give Fedora another go (it's already on Gnome).

Things are smoother since last time I looked. On macOS the installer is downloaded in the form of a "media writer" application that downloads the image you need and creates a bootable USB key - much nicer that the dd business I've been doing.

Gnome is very slick these days and on the three machines I've tried so far everything mostly worked out of the box. On an HP laptop it didn't include the Broadcom wireless driver but that was fairly easily fixed. While not much is installed by default, I quickly wanted the nano editor. Amazingly hackrf was built in.

I'm quickly up and running with fldigi, wsjt-x, gnuradio, gqrx, and all the normal unix goodness. The work done by Ubuntu has raised the standard of all desktop linux distributions (not to mention the whole cloud and virtualisation world) and I'll miss Ubuntu for sure.

Fedora notes for an Ubuntu user

Instead of apt (or apt-cache and apt-get) there's something called "dnf" that replaces "yum". For some reason I find it hard to remember "dnf" and sometimes have to type yum so it will remind me.

sudo dnf update
sudo dnf search xxx
sudo dnf install xxx

I've eventually figured out that DNF stands for "Dandified Yum" but that fact is missing from the man pages. Under the hood it's Linux and all the tricks I've learned are the same regardless of the distribution.

Friday, April 07, 2017

First transceiver with built-in FreeDV

Fantastic to see Chinese ham radio gear for HF increasingly appearing. This one "RS-918SSB HF SDR Transceiver" caught my eye because the operating modes listed are: "SSB(J3E),CW,AM(RX Only), FM, FREE-DV"

That's the first time I've seen a radio with built-in FreeDV.

From the site:

Main Functions

Spectrum Dynamic Waterfall Display

Multiple Working Modes: Receive Mode, Transmit Mode, TUNE Mode, VFO Mode, SPLIT Mode

DSP Digital Signal Processing Noise Reduction

Automatic Notch Filter

Humanized Interface Color Display

Receive Fine Tuning Function, Changeable MIC Gain Value

VCC Power Supply Voltage Indication Table

Transmit Signal Strength Display Table

Multifunctional Instrument: SWR Standing Wave Ratio Meter, AVD Audio Frequency Meter, ALC Signal Modulation Meter

Specifications

Frequency Range - RX:1.8-30MHz TX:All HAM HF BANDS

Operating Mode - SSB(J3E),CW,AM(RX Only), FM, FREE-DV

TX Power - 5W (Standard, DC 13.8V) , 15W (Full,DC 13.8V)

Receiving Sensitivity - 0.11~0.89μV(RFC 50-20)  

Minimum Frequency Step - 1Hz

Operating Voltage - DC9~15V

Antenna Impedance - 50Ω

Frequency Stability -  ±1.5PPM @ Power on 5 Minutes (Standard) ; ±0.5PPM if Optional TCXO Used

Product Dimension (W × H × D) - 215×74×62mm(Mounting Bracket Included)

Weight - 623g

No idea of price yet and it looks pretty clunky but great to see FreeDV built right in.  (If there are others please let me know).

Saturday, April 01, 2017

Built a 2m J Pole out of copper pipe

Just for fun I tried receiving WSPR on 6m. I'm using a half G5RV but at the end of a long run of RG58 so losses at 50MHz are likely to be significant. Quickly VK2HC was received and Peter emailed to say hello.

I mentioned my poor 6m setup and Peter urged me to try a copper J Pole design for 6m. Only when thinking about it at the hardware store did it dawn on my that the length of over 4m wasn't going to support itself and so I chickened out and decided to try the same but for 2m.

I purchased lengths of 15mm copper pipe, an L piece and a T piece along with a small gas blowtorch. The Ham Universe J pole calculator gave me the lengths. Unfortunately I mistakenly cut too short and had to extend later but that wasn't difficult - Lesson: always cut antennas a bit long at first.

Soldering the joints is done by heating with the blow torch until solder melts on contact and then I let that "wick" in to the joint. Seems to work very well. Hose clamps were used to attach the coax (some waterproofing is going to be needed).

Front of house antenna farm: 1090Mhz antenna, 6m slim jim (on a squid pole), 2m J Pole (left to right):



It tunes up pretty well and gives an SWR below 1.1.

Wednesday, March 29, 2017

Decoding pagers with rtl-sdr

This works.

$ rtl_fm -o 4 -A lut -s 22050 -f 148.137M - | multimon-ng -t raw -a POCSAG512 -a POCSAG1200 -a POCSAG2400 -f alpha /dev/stdin
Warning: -o is very buggy
multimon-ng  (C) 1996/1997 by Tom Sailer HB9JNX/AE4WA
             (C) 2012-2014 by Elias Oenal
available demodulators: POCSAG512 POCSAG1200 POCSAG2400 FLEX EAS UFSK1200 CLIPFSK FMSFSK AFSK1200 AFSK2400 AFSK2400_2 AFSK2400_3 HAPN4800 FSK9600 DTMF ZVEI1 ZVEI2 ZVEI3 DZVEI PZVEI EEA EIA CCIR MORSE_CW DUMPCSV SCOPE
Enabled demodulators: POCSAG512 POCSAG1200 POCSAG2400
Found 1 device(s):
  0:  Realtek, RTL2838UHIDIR, SN: 00000001

Using device 0: Generic RTL2832U OEM
Found Rafael Micro R820T tuner
Tuner gain set to automatic.
Tuned to 148401600 Hz.
Oversampling input by: 12x.
Oversampling output by: 4x.
Buffer size: 7.74ms
Exact sample rate is: 1058400.010094 Hz
Sampling at 1058400 S/s.
Output at 22050 Hz.
POCSAG512: Address:  158460  Function: 0  Alpha:   57973-1 
POCSAG512: Address: 2007607  Function: 1 
POCSAG512: Address: 1741522  Function: 0 
POCSAG512: Address: 1705329  Function: 0  Alpha:   69u'2-88

multimon-ng comes from here. I found the frequency by running CubicSDR.

This post is a note to future me.


Wednesday, March 22, 2017

Logitech Brio 4K Pro Webcam review

USB-C is clearly the future of desktop peripheral connection and it's great to see products appearing that leverage this new plug.

I plugged the new Logitech Brio 4K Pro Webcam into a 12" Macbook via the USB-C cable that came with the laptop for charging, it's the first time I've used it for anything more interesting. Here's how it looks (I hadn't removed the protective plastic at this point).


The camera itself is 27mm high and 102mm wide. There's an "on" light, the lens, a microphone and presumably a flash along the middle. Below are left and right microphones.

Note that I did not go and download any extra software before plugging it in so that I could see how the device works "out of the box" on macOS. All good! The camera simply appears as an extra device in standard video apps including FaceTime and Photo Booth.


Here's a comparison with the built-in FaceTime camera in the MacBook. On the left is the Apple built-in camera, on the right is the Logitech Brio.


The Logitech camera is more wide-angle which would be better for capturing a meeting room or small group for a video call. I have to say that the Apple camera is pretty good and if you just want to have video calls from an Apple laptop then you probably would just use the built-in camera.

Image quality seems a little soft, I'm not sure that the auto-focus works as I'd expect.

Physically the camera's stand is very clever and the rubber coated clamp mechanism allows the camera to be mounted on a laptop screen or to stand on a desk with ease.



You can squeeze the clamp and it stays put either gripping a screen of various widths or just standing on a surface. The little stand disconnects to reveal a standard 1/4" tripod socket which is very convenient.

Software


Additional "settings" software is available for download. It takes almost 70Mb of space once installed which is a little more than I'd expect.

Image quality viewed through the settings software is much better which suggests that video conferencing apps are not making use of the 4k resolution. Also there is the option of a 90 degree wide angle mode - so the default is zoomed. (Click the image below to zoom in).


The first panel lets you zoom the camera in and digitally pan left, right, up or down.



There are also additional controls for the image.


Surprisingly (to me) you can run the camera control app along side another app using the camera and make adjustments, here it is zooming in while using FaceTime. (I'm available for a Terminator re-boot by the way... oh).


Conclusion

The Logitech Brio 4K Pro webcam retails for AU$379.95. On a Mac it worked "out of the box" with existing apps including FaceTime and Skype. It did not work with iMovie X for some reason.

If you have a computer with USB-C then it's fantastic to have a peripheral that can plug right in. Logitech includes a USB-C to USB-A cable in the box so no problem if you haven't moved yet.

The image quality is good but looked a little soft, this might be that what I'm comparing to has done extra sharpening. Detail in shadows is better than the build-in camera on an Apple Macbook but might be much better than some other laptops.

As a camera for videoconferencing the 4K resolution is really a waste but the ability to zoom in on part of the frame makes the extra pixels useful.

My thanks to Logitech Australia for the loan of a review unit.

Monday, March 13, 2017

Simple ground stake for supporting squid pole

I was very impressed by Peter, VK2AQJ's method for standing up a squid pole for supporting his portable antenna and decided to reproduce it. Some 20mm angle aluminium and angle brackets was purchased at the local hardware. The aluminium I got was 1.5mm thick and 1m long.


Hack-sawed a point to make it easier to push into the dirt.


The right angle bracket is bolted on and can be used to push the stake in with your foot.


Peter had also added a screw terminal so it can be used as a ground connection but as I'm using a dipole decided to skip this.

In use I feel that 1.5mm aluminium and the angle bracket are a bit low in strength but probably OK as this is QRP we're doing here.