Radio and Pi Archives - Page 3 of 3

Radio and Raspberry Pi

I still haven’t got my radio set up but I’m working on it. Playing with a Pi seems to have taken precedence for the time being. The major obstacle is getting an antenna up and the co-ax run. All in good time though.

I was thinking that when I get the radio set up I’d like to play around with the Pi and KX3 hooked together. Maybe some FT-8, PSK, etc. Maybe one (or two) of those new fangled D-Star / C4FM dongles.

Seeing as I use my current Pi as a web server / storage box for movies and TV series and it will soon have a TV tuner HAT or dongle attached it lives right by the TV. If I’m going to use a Pi for radio stuff it looks like I’ll need to get another Pi.

There’s lots of thinking about it all in the works at the moment but very little actual action. Getting this web site happening the way I want it to seems to have taken priority. Of course other bits of life get in the way too.

Getting rid of the heat

So when I use the Pi to watch movies on our TV it tends to get a bit hot under the collar – up to around 81 or 83degC. Something needed to be done about that state of affairs so I installed it in a heatsink case with fans.

Much better. No matter what I do I can’t get the temperature over 55degC.

While I was at it I decided to go with the 64 bit kernel so I added arm_64bit=1 to config.txt so now uname -a gives me :-

Linux markpi 4.19.75-v8+ #1270 SMP PREEMPT Tue Sep 24 18:59:17 BST 2019 aarch64 GNU/Linux

Everything still works as it should – Apache2, PHP, MySQL and VLC which we use a lot for movies, tv series, etc.

The next step is a TV HAT or a TV USB dongle – probably the dongle as that won’t mean messing around with GPIO standoffs, etc to get it to fit with the heatsink.

Travelling and playing radio

When we’re out and about I always have the KX3 and stuff with me. I leave the PX3 at home though. I power it all with a home built 10Ah LiFePo4 battery which gives me quite a while at 50W from my KXPA100.

Antenna is usually a doublet of about 50 feet / leg and fed with 300 ohm TV antenna twin lead. Needless to say some sort of impedance matching is required so I use a home brew Z-match ATU. The centre of the doublet is at around twenty feet on a squid pole.

Sometimes I use a 53 foot wire which is end fed via a 9:1 unun with about 20 or 25 feet of counterpoise. I prefer the doublet though. Another antenna I use a bit is 50 feet of zip cord with one conductor stripped off at 35 feet. Both antennas work pretty well for what they are just heaved into a tree if there’s one available. No trees ? I use the doublet.

One of my projects (apart from all the others) is to get a Pi 3 together for FT-8 and PSK and logging and do some really compact portable digital stuff – the thought of lugging a laptop and associated stuff around just doesn’t apeal.

VK3KW

Located in Moe Victoria, Australia in grid square QF31dt. Moe is located about 130km’s south east of Melbourne in the Latrobe Valley in South and West Gippsland.

My station consists of an Elecraft KX3 (serial 1675) with all the trimmings – KX3, Roofing Filter, 2 metre module, ATU and charger/real time clock. I also have a KXPA100 (0530) with inbuilt ATU and a PX3 (233).

My antenna is a 43 foot vertical with a few counterpoise wires with an LDG RT/RC 100 at the base. I wish I could have a tower with a Yagi but as we are renters that’s not an option. On the boundary of the property there’s a great big Eucalypt about 30 metres tall which will quite possibly be pressed into service for one end of a random sloper of some description.

I also have a Yaesu VX-7R, a Yaesu FRG100, a Yaesu FT-817 (non ND) and an old Eddystone EB35 MKII in perfect working order apart from a bit of deafness on FM. Sooner or later I’ll get around to fixing that though. Of course I have sundry small portable receivers – mostly Sony.

When I get around to it I’ll put up a few photos – probably about when I get around to fixing the Eddystone.