RaDAR – Preparing to work Bouvet island DXpedition

This DXpedition is within reach of South Africa and in particular RaDAR Ops! I’m not a DXer as such but would like to do some chasing on this one.

My usual wire antennas would probably have to be improved upon to ensure success. Antennas that have served me well in the past are the delta loops and I consulted an article that an old friend wrote a few years back. It can be seen at  H5ANX Delta loop antenna

The standard formula, 286 / f in MHz is used to give the loop length in meters. For 20m it would be 20.15m, the same length of wire used for a 40m end fed via an end fed tuner. That means I can use the same wire for a “20m / 10m” delta loop that is capable of being used on 17m / 15m and 12m using a tuner – or just carry two lengths of wire, one for the “20m / 17m / 15m / 12m and 10m” multiband delta and the other for the 40m end fed. The proof of the pudding applies as always, of course!

If the delta loop is fed from a corner via the 4:1 balun the polarization is vertical – nice for DX! The delta loops are also not critical about height either. All these parameters fit in very well with RaDAR!!!

Like the short coax feed from the rig to the end fed tuner, the same short length can be used to feed the 4:1 balun. Dual function hardware in the pack.

This is what I’ll use for Bouvet and of course the 897d at 100W for a little punch. That means I must refit the LDG AT-897 Auto ATU …. it has presently been removed.

Let the games begin!

Some tree deployment options …….

Update 2018-01-31

The 20m full wave deĺta loop – Measured 20.3m and eventually trimmed 600mm. Practically zero SWR across the whole 20m and 10m bands on the 817’s meter!!!

 I was a little concerned about why I needed to trim so much and discovered this excellent PDF on delta’s. See Delta loop presentation

Amazing, the dramatic effect of insulation on the wire!!! I use “Twin flex”.
Hanging the apex of the delta from a tree limb and tying the bottom two corners down with tent pegs allows for tilt if need be for directional gain. Tuner not needed if only used as a dual bander (20m / 10m)  Fantastic!!!

RaDAR – Analysing the challenge logs

Not everyone submits a log especially that the RaDAR challenge is really a challenge against yourself but also good to compare other’s results to see if you’re doing OK or not.

Being international and having to choose a four hour period within a twenty four hour period, we don’t have the same proximities or propagation conditions so “apples with apples” could never be compared.

Usually QRP power levels are more difficult to use but power output categories are not defined as it balances itself out as a weight issue if you need to carry the kit. Usually around 20 Watts is a good average for reasonable success.

I received a log from Thomas, DG1PY. Firstly I was very impressed to see Germany taking part. Thomas’s log was also very well presented.

Thomas made three transitions which I think is a good average. What’s interesting here too is that only the first five QSO’s can count but the sixth one is considered gentlemanly. So for this deployment the score would be 15. Thomas mentioned there was a contest on the go and that sometimes makes it difficult for RaDAR to RaDAR contacts in order to achieve bonus points.

All three deployments in Thomas’s case had similar results which gives him a total score of 45 which is really pretty good! There you have it, how did you compare? Thomas may try transitions on a bicycle during the next challenge which will also be an interesting challenge. It’s also great to mix various transition methods.

Some take on the challenge as a group and some take it on alone. To be quite honest, I prefer to do it alone, not that I’m not a team player but the challenge is to have a well focused team and that’s a challenge in itself!

We will see the next challenge in April……

73 de Eddie ZS6BNE


Photo : The SARL Summer QRP Contest 2018-01-27


RaDAR – For the non builder

Well I built the 49er and was very impressed with it’s simplicity and effectiveness! Maybe some young ham could use it as a first CW rig at minimal cost! Already built!!!

Same goes for the more advanced QCX!!!

Let’s see how many would be interested in a good first step into amateur radio.

Update 2018-01-12

All gone to a good home, the circle is getting bigger!

Now I’m wondering if I should not let the HB1A go too? I do have a 817ND for QRP and a 897d for QRO?