The YouTubers BunchCallum’s Videos
Is it true that coax needs to be 18 feet – or multiples of 18 feet for your CB Radio? I’m going to address the myth about specific lengths of coax that some CB operators believe will magically match their antenna to their radio. We’ll explain why the impedance along the coax varies with frequency and length, and how a mismatch can cause losses and affect the SWR of your system. We’ll also give practical advice on how to properly match your antenna to your radio and minimize losses.
Callum.
Loft / Attic Home-Brew CB antennas. Three Rules: Needs to be compact, easy on the wallet (cheap!) and easy to construct and understand. I have built loft / attic antennas, both verticals and dipoles for 11m (10m actually) with varing success. Other ideas are Delta Loops, horizontal loops and also remember commercial mobile antennas can ideal for lofts and attics – you will need a bit of a ground plane though. Chicken wire or just regular wire can assist. Beware that loft antennas can sometimes sound noisy because they will be directly above all the electrics in the house. However, they are still cheap and fun to make. Good luck, Callum.
https://youtu.be/V8Qq4-0_TjQ – Tribander SkyLab Tribander
https://youtu.be/xfX_8rogur8 – Delta Loops
Callum’s regular Friday Fun on Ham Radio. Join in, see if you can hear me or just listen in. This is a hobby – so let’s have a laugh. 73. Callum.
I wonder if you can hear me? Join in the chat, listen in – or see if you can hear what I can hear? All for fun and games on Sunday. 73, Callum.
If you want me to build this. Let me know. However, in this video I explain the principles behind antenna design using Maxwell’s equations and the moment method starting with a simple vertical antenna, I demonstrates how we can predict resonant frequencies and also how we can make the antenna shorter while still maintaining its resonant frequency.
Then, let’s look at adding a coil to a vertical antenna, and how this affects the resonant frequency of the antenna’s harmonic – for instance how 7MHz is also resonant on 21MHz. Using a combination of the moment method (software simulation) and spreadsheet calculations, I’ll demonstrate how the position and value of the coil can change the antenna’s harmonic frequencies.
This video is a great resource for ham radio enthusiasts who are interested in understanding the technical aspects of antenna design and how to optimize their antennas for specific frequencies. Whether you’re a beginner or an experienced radio operator, you’ll find valuable insights and practical tips in this informative and engaging video.
In a nutshell, this isn’t an end-fed but a Dipole or a Vertical. I am VERY excited about this research. Can it be right? Using a loading coil to pull the 3rd harmonic for 21MHz down to 14.2MHz. Let me know what you think – then we can head out to the field and see if this works.
OK, we have enough for the next 100 Signature 9 DX Commander Antennas. Order now for delivery within a week or so. Buy here:
And have some fun!
Callum, Wendy and Loki.
Live again on Friday morning, 24th February 2023. See if you can hear us, join in or just listen. It’s Friday Playtime! Callum.
There is this rumour going around that 2,000W amplifiers are a total waste of time. You are missing a HUGE point. The ability to handle high levels of output without overheating needs thinking about. So why settle for a low-powered gear that melts under the stress of continuous-duty modes like FT8 or and RTTY? I happen to love my Acom 2000 for the durability and performance.
Let’s play ham radio, my science hobby. It’s fun to participate in and discover the joys of radio. Call in, join in the chat – or just listen. It’s up to you. All welcome.
Quick skim over building the Pre-Production Signature 9. The 10m element MIGHT change in the future, as an option to achieve very slightly better gain on 10m. Else, this is the cut chart:
If you are reading this line, then the User Guide is still under review – so run with these numbers please:
CUT CHART (that means *CUT* the wire to this length below – don’t ADD on the loops etc to the cut)
Band / Cut (in metres) [intermediate tensions use up this much in cm]
* 40 – 11.55m [there are two tension loops as discussed – they use up 10cm + 10cm]
* 30 – 7.94m [there are two tension loops as discussed – they use up 10cm + 10cm]
* 20 – 5.78m the foldback is 1.05m
* 17 – 3.96m assumes foldback is 6cm
* 15 – (as 40m)
* 12 – 2.83m assumes foldback is 6cm
* 10 – 2.5m assumes foldback is 6cm
To clarify: For instance with 40m, CUT to 11.55m. Same with 20m, just cut your wire to 5.78m. This caters for tension loops and foldbacks.
QRO: 10m foldback. See the User Guide for QRO modification on 10m band, ujsing a closed loop system.