CQ DE VK7BEN

Just another Amateur Radio Operator

Author: ben Page 3 of 4

Letting the Smoke Out I

Oops

Above is a rather fine example of letting the smoke out. My last post talked about replacing a dipole that had worked well for many years but suddenly not so much. With the options of breaking it all apart to check the inside pieces, or throwing out the antenna, I chose the former.

What you are looking at is a very cooked load. Originally 9 10k ohm resistors in parallel are now well in truly charred. behind this (as evidenced by red winding wire) is a ferrite rod with a coil wrapped around it, in parallel with the resistor bank. These loads are used to give the antenna its low SWR across all bands.

Cooking the loads occurs when you forget there is a difference between Px and Py power and also forget that most baluns/loads can take a greater amount of the former over the latter. In this case my new radio allowed me to transmit 100 watts of PSK31, when the antenna was only rated for 50 watts.

It’s not out of the realms of possibility to repair this, should the ferrites in the loads and balun still be in working order. However when you take into consideration that I am would probably need to replace most of the stainless steel wire, obtain replacement resistors and still end up with a balun of questionable integrity (due to aforementioned power excesses), it may be time to recover what I can from the antenna and throw out the remains.

New HF Antenna for Home – an OCF Windom!

OCFWindom

When I made up the 4:1 balun earlier this week, I didn’t realise that I would be putting it to use by the end of the week!

Ever since I got active again, the commercial multi band dipole that I had been using for many years was no longer working optimally. When I first purchased it, it had an SWR of < 1.8:1 across most bands, but recently the SWR had had risen to around 2.5:1 across most bands. After discussing and troubleshooting the issue with the antenna manufacturer, it was decided the cost to replace faulty parts exceeded the original purchase price of the antenna.

It was time to replace the antenna.

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Building A Balun

Testing the Balun with 200 Ohms and an Analyser. Looks good to me!

Testing the Balun with 200 Ohms and an Analyser. Looks good to me!

Baluns have always been a bit of a homebrew boogeyman to me, mainly due do what appeared to be some sort of magical winding technique around a toroid. However, given the prices of baluns these days seems to range from $60 AUD upwards, given I have all the parts already at home to make one (“free”), I decided to bite the bullet and learn how to make one.

I’m not going to bore you with the details on how a balun works here, other than to say I think they are useful for connecting coax to antennas. Ladder line, while more efficient, doesn’t have a very good use-case for my applications and good quality ladder line is also expensive and difficult to obtain compared to the plenty of coax I already have available to me.

Shout out to VK6YF whose diagrams for the 4:1 Ruthroff voltage balun were what I used. Some people will be quick to tell me that it was odd to make a 4:1 balun when I am not using ladder line – I agree (and in hindsight should have made a 1:1 balun), but this was about learning how to make a balun.

You can imagine my surprise after being having my build peer reviewed by my good friend Murray that other than a dry joint that was soon fixed, the balun actually worked! to put this in context, two previous attempts at building a balun had resulted in wildly varying SWR and resistive load that on the whole didn’t look much better than just using a piece of wire.

Anyway, now that I know I can build them, I will obtain another jiffy box to build a 1:1 balun for use with my upcoming portable dipole!

 

Going Mobile

QRV Mount Rumney

Mobile test run at Mount Rumney. not a bad view!

For a long time it has been a goal to take my own station portable to work HF. This week I finally achieved that goal.

It’s taken me a long time to get there, with the project starting in 2006 when I purchased a portable aluminium mast for the car that can be assembled as high as 12m (39.3 feet). With the help of Bruce (ex VK7MBD) a custom tow bar mount was made, allowing the assembly and raising of the mast to be possible by 1 person. After this, things went quiet on that project as a result of my hiatus from the hobby.

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Yaesu SCU-17 – The Missing Manual

Yaesu SCU-17 Unit

Yaesu SCU-17 Unit

Although it is almost certain that future generations (and the more expensive versions!) of radios will have rig control and digital mode keying built in with just a USB cable to go between radio and computer (such as Yaesu’s FT-991), for previous generations of radios, such as my FT-DX1200, the Yaesu SCU-17 Interface is required to act as that bridge between radio and computer.

There is nothing particularly special about the interface – you could make one yourself at home if you wanted. It consists of 2 USB to Serial ports, a sound card interface and a little bit of wizardry to wire it all together. As for me I’d rather just spend the money to save myself the hours of frustration of putting one of these together (and troubleshooting issues) and end up with a professionally made, compact unit.

However what I wanted to address was the distinct vagueness of documentation around that covers how they operate.

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Power Distribution in the Shack

WARS Powerpole Distribution Box

WARS Powerpole Distribution Box

Once you start accumulating more than a couple of pieces of radio equipment, the questions around power supply quickly comes up. Radios can quite easily draw in excess of 15 Amps @ 13.8 Volts depending on the model. My two main HF rigs have a specification of 23.8 Amps and 18 Amps respectively. This is generally more than your standard off-the-shelf supply.

For domestic consumption, linear type supplies (Transformers) are only really viable up to 25-30amps. After that the cost starts going up significantly, as does the weight of the unit. Thankfully switch-mode technology seems to have come a long way in recent years, which resulted in me purchasing a 40 Amp power supply, and no noticeable RF QRM.

With power sorted out, the next thing to deal with is how to get the power from the supply to the devices. With a 40 Amp supply, you can power a whole lot of things, but I quickly discovered the posts only allowed me to connect 2 devices after I attached lugs to the leads. Also, lugs generally are not that portable going across different power supplies – what works on my QTH setup will not work in my car, or at someone else’s house. There had to be a better way.

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2015 CQWW SSB DX Contest

The CQWW DX Competition would have to be the biggest radio contest of the year for the casual contester such as myself. It is also important reminder that you need to be under no illusion of the capabilities of your equipment, otherwise you may quickly find yourself very frustrated.

This is my first crack at CQWW since 2011, and I have entered with the goals of beating my 2011 score of 2160 and working some new countries. 0000 UTC is 1100 AEDT so I allowed myself to sleep in, get up and get ready. I was on the mic and ready to go as the clock ticked over to start time.

So you can imagine my early frustration when I couldn’t make a contact. I could hear the stations just fine, but they could not hear me. It actually made me question whether my station had suffered a critical failure while I was sleeping and was not transmitting at full power. Truth of the matter was that my station is quite meagre compared to many of the other stations on air and 100 watts into a dipole that is barely above ground level, along with an ordinary geographical location means that I simply do not have the power to punch through closed bands, I need to wait for them to open.

So I went outside to do some gardening.

The 20m band finally opened for me around 0500 UTC and from then on it was search and pouncing for the next 3-4 hours, occasionally listening on 15m. As usual, it seems the bulk of my contacts come from CQ Zone 15, though I was pleased to work USA later in the evening on 40m. Definitely the highlight of the evening was working VP2MDG in Montserrat late in the evening on 20m. The band should have been closed at that hour, but he was booming in!

Sunday followed much the same pattern as Saturday, except the 15m band was not really open for me this time around. by 0700 UTC I had become tantalisingly close to a 10,000 point score, with less than 500 point required. To my frustration, the 20m band started to close up at the same time, and those last 488 points took 1 hour to make with 2 QSOs.

At 0834 UTC  on 25/10 I finished up my competition operations with a total claimed score of 10,602.

This contest does indeed seem to be the most difficult of the contests, when in theory it should be one of the most straight forward. You become very much aware of the capabilities of your station, and when the bands are open for you. You learn to have some level of patience, and you learn to come up with different phonetics to make your callsign heard:

  • Victor Kilo Seven Bravo Echo November
  • Victor Kilo Seven Bravo Egypt Norway
  • Victor Kilo Seven Bravo Easy Nancy

It was very much a battle of the linear amplifiers for many people, and I was amused to hear many of the splatter in some cases over 5-6KHz across the band, which is not something you are meant to do.

Some lessons were learnt this year, and I think next year I may take my station mobile to gain some crucial elevation. I think by next year a significant amount of servicing will be completed to my feed lines and antennas to ensure they are working at an optimum level.

Definitely what I thought was going to be a simple contest was anything but.

     Band QSOs Pts ZN Cty
       7   5   9   2   2
      14   56  156 18 36
      21   2   6   2   2
Total      63  171 22  40
Score: 10,602

QSL Cards

QSL Card

“A QSL Card is the final courtesy of a QSO” – ARRL Operating Manual for Radio Amateurs

In recent years online QSL services such as eQSL and the ARRL Logbook of the World would have you believe that confirming DX QSOs has moved into the electronic world and QSL cards are no longer required, however I still find it quite enjoyable to receive real paper QSL cards in the mail – I think its a lot more personal knowing that someone has gone to the effort of sending you a card rather than having a computer automatically generate a message and upload to the internet. I’m not the only one, with local operator VK7GN having an amazing QSL collection that was featured on TV.

It’s been a long time since I made up QSL cards. My last QSL cards were single sided, with 1/3 of the card taken up by a picture of my IC-706MkIIg and the brief information and QSO details. This was printed onto matte 4×6 photo paper and I wrote on them and sent when QSL cards were received. I wasn’t terribly happy with these as they felt a little cheap and flimsy, and were not the standard QSL card size of 140mm x9 0mm.

Following the OCDX Contest I felt it was inevitable that I would start receiving QSL cards again and that I should have some QSLs cards of my own to reply with. I started by searching the web for QSL card printers, and while many were out there the pricing was getting expensive (the $AUD has *tanked* in the last 12 months) and not being sure of the quantity I required it was a bit of an undertaking, so I decided to create and print them myself.

Using Photoshop and Pixelmator and using one of the photos I took of the Aurora Australis, I had a look around online at what some other QSL cards looked at before finishing my design. After that I had a bit of fiddling to do to get the card front and reverse to line up and fit 3 to a A4 piece of card to print. I then trimmed to size with a guillotine.

I am pretty happy with how these have come out. They look good, they feel good, and I will be happy to start sending them out as QSO confirmations as I receive QSL Cards.

 

Oceania DX Contest 2015

Contesting Screenshot

If my saved contest log files are anything to go by, this is the first Oceania DX contest I have participated in since 2008.

I’ve been looking forward to this contest now, as it is one of the “big ones” for the year, and a big opportunity to obtain some new DX countries. It guarantees me a eQSL eDX award as well as more uniques DXCC. It also means I really need to get around to getting some real QSL Cards printed (Do people have suggestions?).

It made for a bit of a busy weekend, as most of Saturday was spent cruising around Hobart, getting home in the afternoon an then settling down to contest in the evening (0800 UTC = 6pm AEST).

I decided to use the N1MM+ Logger for the contest. I have used it before in the Penstock Lagoon RD Contest, where it worked well but was largely hampered by not having a definition file for the RD Contest. N1MM+ does know about the big contests though and I was keen to get hands on with it again.

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Packet Communications!

First Packet Connection

I’ve played about briefly with AX.25 in the past when tinkering with APRS, but never really had much success with it and with TNCs being both hard to come by and damn expensive for what they are, it has always been out of my reach. Recently I acquired a couple of second hand TNCs and have spent the weekend setting up and connecting.

The first TNC I attempted working on was a Paccom TNC 320. This meant creating a cable to go from the 5 pin DIN connection on the back of the TNC to the 6 pin mini-DIN connection in the back of my ICOM radio. The first attempts at this involved using the mini-DIN tails from old PS/2 Mice or keyboards, testing to see if their wired up pins were going to be any good for the TNC and then just soldering the 5 pin DIN on the other end. I spent an evening with VK7ZMS doing this and after much testing, we got to the point where we had PTT and 1200 baud AF working, but no RX. Even then. the AF out tones were low.

Over the weekend I bit the bullet and visited Jaycar and bought some more mini-DIN, 5 ping DIN and multi-core wire and created my own cabling. This time I was also armed with an MFJ-1270B TNC which was my fallback option if I had no luck with the Paccom.

Plugged everything in, fired up a Putty serial connection, got presented with garbage. Changed the terminal baud settings, still got presented with garbage. Thought at this point it’s probably a good time to read the manual. Interesting thing about the MFJ TNCs is that they use 7 bit words, not 8 bit like many other devices. Updated my settings and bingo, was presented with text that looked like a TNC.

Ran the calibration tests, PTT worked, I could hear tones being sent loud and clear, and most importantly I was receiving packets as well. I was in business. Finished assembling the cable, plugged everything back in and found I had Rx, PTT but no tones out. Back to workshop again and found in the final assembly I had caused a small short across some of the pins. I fixed the issue, liberally applied hot glue to hold it all in place and provide isolation and put it all back together again, and now it works!

As you can see above, I have managed to successfully connect to VK7ZMS. I have also connected to VK7HDM-9 using VK7ZMS as a via.

I already know of a few other amateurs getting interested in packet again, so who knows, we might see a bit of a packet radio revival in southern VK7!

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