NARSA Rally 2023

On the 23rd of April it was the 2023 NARSA rally.

This year marked a change in how the rally was being approached. Increasingly and particularly thanks to Covid (or at least so I understand) the larger traders have been staying away from rallies, not seeing it worth their while, so NARSA decided to focus less on big traders and more on clubs and what clubs have been doing.

As a club we decided to try to build on what we’d exhibited last year. In 2022 alongside the usual selection of club projects on display we had a satellite ground station receiving video from QO-100. This year rather than just receiving we decided to put on a fully operating narrow band ground station which we operated throughout the day, in addition we had a camera on the station, the video from which we transmitted across the room via a 5GHz link and then streamed to the BATC streamer via a Portsdown device. Putting all this together was a big job, and I learned a lot through assisting.

It was a very enjoyable day and I thought the mix of club stands and smaller traders was great, in particular there was a fantastic selection of components, I’ll definitely put some more thought into what I need for the shack before I go next time.

Hopefully the club focused aspect will continue to grow and it’ll continue to stand as a real radio amateurs rally furthering the hobby!

Some DX Operating /M On 10m

I’ve had a couple of exciting contacts this week operating from my parked up car (I use G5JIM/M but probably could be G5JIM/P).

Firstly I managed another contact with N1MX which was nice as I’ve now worked him (and transatlantic) on 2 different bands. The next day I then managed a really enjoyable QSO with 9J2BO in Zambia, very exciting indeed!

Low Pass Filter

The LPF really goes together with the PA, in the GQRP Scratch QRP documents it suggests building and testing them together, however I hadn’t worked out which capacitors I was going to use so I built and tested the PA and then the relays before coming back to this. In the end I used some silver mica capacitors which I purchased from Hifi Collective, they are a little pricey compared to normal capacitors, however they had the values I required so no doubling up etc required and they more than meet the requirements.

No huge issues with this build apart from removing the enamel from the wire for the inductors, burning off with the soldering iron is my preferred method, however I still struggle to get it burnt off enough and clean enough to easily solder. My connections seem decent but I feel like either I’m doing something wrong or there must be a better way, yet scraping off with a knife or using sandpaper seems slow and a bit ’iffy’.

Relay Board

I’ve got moving a bit again on the sudden transceiver project, after completing the PA earlier in the week I’ve got the relay switch board sorted and tested, this switches both the antenna (relay on the left) and 12V supply (relay on the right) between the RX and TX chains and sets the D4 pin on the Arduino high to tell the VFO/BFO module when we are transmitting.

Sudden Power Amplifier

So five months on from preparing the board I’ve FINALLY got round to completing the PA, I had a couple of hiccups but no huge dramas, other than a short circuit which lead to some smoking wires!

First of all despite getting the voltages where I expected I wasn’t getting any current flow, with the help of one of the club members, Dave G8KBB, we discovered that I had a dodgy solder joint, one of the wires I was using too connect a couple of MeSquares wasn’t soldered down air one end, we then discovered that I didn’t have the threshold voltage right, once we discovered that it started working very nicely.

I’ve attached the IRF510 to a heatsink to keep my mounting options open, but most likely I’ll get a metal case and bolt it to that, if not I’ll keep the heatsink, detach the solder tag, bend the middle leg up and attach via a piece of wire.

FT8 – How (Not) To Cause QRM

This is a complete beginner post, but I was inspired to write it after seeing a question on Facebook by someone new to FT8, he had completed a QSO with someone, then got a message QSYQRM followed by AHOLE. He was questioning how you QSY (change frequency) on FT8 and if he’s done anything wrong, the operator in question had never altered the settings as he didn’t want to mess anything up.

The response here is clearly rude, totally unesscesary and possibly against license conditions depending on one feels about the phrase used (and the specific license conditions)…however the operator was it seems (unwittingly) causing QRM, so how?

Not wanting to mess things up the op didn’t adjust any settings, so he was just TXing on the frequency that happened to be in the Tx box or whatever frequency he might have set when clicking on the waterfall or selecting a call to respond to.

So how to avoid this?..first of all read the WSJT-X documentation, that should be obvious, but it really is a good document so make use of it, specifically take a look at the FT8 Basic Operating Tutorial…that being said there are a few steps it’s worth pointing out:

  1. Just Listen First – When you load up WSJT-X (or whatever software branched from WSJT-X you use) just RX for a couple of mins, watch the waterfall and…
  2. Select A Clear Frequency – Yes, you need to choose the frequency you’ll be TX-ing on, don’t just leave it where it is, you need to be actively involved to avoid causing QRM.
  3. Hold Tx Freq – This isn’t actually a must-do for using FT8, but the problem with hopping to the frequency of whoever you are responding to (when you double click on the decoded text) is that it might not be clear of activity for the opposite time slot, holding your Tx frequency ensures you are in control of where you are Tx-ing and avoids landing on top of someone…this is annoying when it happens to you, even though it is generally very innocent.
  4. Listen Again – This is really to avoid you being the victim of QRM, take a break from transmitting to check that your frequency is still clear, someone may have accidentally ended up on your frequency (you might be able to hear them, they might not be able to hear you). Regardless of whoever is at fault you’ll probably want to move to avoid interference in either direction.

This isn’t very in depth but hopefully it highlights the important basics to avoid causing QRM.