Monday, January 24, 2022

Using an IC-705 remotely from macOS using SDR-Control

It is hot in my shack here at the moment and I can't stand it in the shed for more than a few minutes so I decided to buy a new macOS app called SDR-Control and try the IC-705 remote feature.

Set up was easy but you do need to note the IP address given to the radio over Wifi (it would be lovely if the software could find radios on the network).

My shack is a fair way from the house and the two are linked with a Google Wifi mesh network. Despite the multiple hops control, audio and the waterfall all work well.

Sound on the Mac laptop sounds excellent and the waterfall is quick to update. Note that you can't show the whole band, only the centre mode works. Like on the radio, you can click on a signal to tune to it.

I'm still learning how to use the software, parts of it are not quite what I expect, the user manual is here.

My only complaint so far is the difficulty of tuning. It looks like it supports the mouse wheel but I'm on a laptop. I wish there were a set of keyboard tuning up down step commands. I asked the author Marcus about this and he said it was not possible directly but you can make keyboard commands to step up and down and another to set the step size.

Some of the user interface is not very "Mac like":

Some of these squares are on/off buttons, others, (like band and mode) are drop down menus. Right clicking on many of these squares does other functions.

I hope Icom releases an update to the IC-7300 with network access (both Ethernet and Wifi please).

My congratulations to the author Marcus for an good piece of Mac software. It looks like a version of the software for Flex radios.

Sunday, January 16, 2022

An off centre fed dipole antenna for more bands

It's been great having a dipole up high in the trees but I wanted to be able to use more bands so I made an off centre fed dipole, cut for 80, fed with a 4:1 balun. This gives me a number of bands with a low enough reactance that the IC-7300's tuner can match it. Here's a plot using AntScope2 on macOS.

The grey bars are ham bands. I'm sweeping from 3MHz to 30Mhz. As you can see I get low SWR on 80m, 40m, 20m, and 11m. With a manual tuner I've been able to use 30m but it's quite a stretch.

Speaking of stretch... The antenna wire is half of a figure-8 speaker wire and I think it is slowly stretching. I had a doublet for 160m up but the wire broke.

I did notice that 40m on the OCFD was not as good as it was on the dipole cut for 40m but the extra bands and convenience make it worth while.

The shack is improving! I ordered a 2m bench, a gas chair, and a 4 draw unit from Ikea. Delivery cost almost as much as the furniture. 

The afternoon sun hits the other side of the corrugated iron in front and it gets very hot. Next step is to insulate and line that wall at least. 

Update: Winning at WSPR reception

It's a combination of height, antenna and of course the low noise location. I'm pleased to see that after 24 hours of WSPR reception on 40m I'm at the top of the global chart by accumulated distance.

The WSPR challenge is a wonderful idea. I love the concept of competing by reception rather than transmission.

(Of course it's a bit unfair as we VKs are very distant from most stations so we have an advantage).

Thursday, January 06, 2022

Another antenna improvement - more height

At my new location I was able to throw a line up a tree to support the balun for a 40m dipole. Dallas, VK3EB, kindly visited with an 18m squid pole and was able to get a line over a much higher branch. 

With extra height, reception, as measured with WSPR, is visibly improved.

Sincere thanks to Dallas for visiting and helping to improve the antenna.