Category: Technology

End of this contest…

by Jurgen

In the last 2 weeks I have been working hard to get my band decoder up and running and to prepare for next contest: the ARRL RTTY Roundup (in which I placed first in M/S LP non W/VE in 2013).

Yesterday I made some QSOs and everything worked all right.

This morning I click on a dxspot on 12m and have my logging program turn the rotator… a few seconds later: no more signal on the receiver.

Something has gone wrong on the Big Boy Rotator and, of course, before I noticed it had overturned and broken the coax cables for my WARC rotary dipole.

The 10-15-20 beam is working OK and the rotator seems to turn but with no correct indication of the direction. I guess this contest has already ended for me this time.

Next big RTTY contest on my list is WPX in a months time…

So, todo:
– find someone to climb the 15m tower twice
– fix the rotator or find a new one
– fix the broken coax

Anyone some money to spare to help me buy a SteppIR DB-18E so I can replace the good old FB-33 while we’re climbing the tower anyhow?

Inrad HF Triplexer more news…

by Jurgen

The news is… there is no news. 🙁

On august 30. I received an e-mail from Appellofunk (the dealer where I bought the triplexer) stating: “if you like please open the TriPlexer to see what happend.”

So that’s what I did and that same day I sent them pictures of the inside of the triplexer showing at least 2 burned (probably more) SMD capacitors.

Since then, no more news.

E-mail between Germany (Apellofunk) and the US (Inrad) must be going by boat I guess…

Pretty frustrating!

 

Inrad HF Triplexer

by Jurgen

My new contest secret weapon worked very well… for exactly 1 QSO.

For the moment I have only these (permanent) antennas for contesting: a Fritzel FB33 3-element tribander at 16m and homemade inverted V dipoles for 40 and 80m at 15m.

So for SO2R I have always used an extra Fritzel GPA404 vertical for 10-15-20-40m. But to avoid the hassle of installing this antenna before the contest and taking it down after the contest I recently decided to purchase an Inrad HF Triplexer so I could use the FB33 on 2 bands simultaneously.

Last week I had the specs of the Triplexer tested by Luc ON7KZ and all seemed to match the specs as in the Inrad web page.

I installed the triplexer between my Sixpak and the FB33 the day before the contest but I didn’t have enough time to thoroughly test it. (I did check all connections twice though!)

Once the SCC Rtty championship started I made a S&P QSO on 20m and during the QSO I saw the SWR on 20m going up to alarming levels :-(.

Continue reading Inrad HF Triplexer →

Designing antennas using a genetic algorithm?

by Jurgen

A few days ago I found a nice piece of software on the internet: BoxCar 2D. This is a way to design a car using a genetic algorithm: a population of cars is created at random and then tested on a track chosen by the user. Then the best cars ‘mate’ to get a next generation. Together with a set mutation rate the cars improve over the generations.

Warning: watching this is addictive, it’s far better than television!

My programming skills are rather limited but I wondered if someone maybe could design antennas using one of the (mini)NEC engines and this genetic system?

Update: it seems that this is not such a new idea, at least for developing antennas. A little googling for ‘genetic algorithm antenna’ gave me some 160000 results 🙂

SuperNec seems to be great software for this but at $6080 it seems I’ll stick to Eznec and MMANA for a while.