Ahh the fun of waiting for a license upgrade, I keep reloading the ACMA licensing page too see if my advanced license has been processed. No joy yet.
Even though I did the exam the end of December, the WIA offices (they do the exams) have been shut till last Monday, so one long lead time here.
It will happen, hopefully before next week.
~Ivy
As discussed before, my home qth has a lot of issues with electrical noise, some of it is self generated (computers and other electrical appliances) and also due to my location in suburbia.
The new receiver we got last weekend the kenwood r-2000, is effected by it as well, but not to the same extent as our other radios. And for the first time I can actually listen to the 80 metre band.
I really do need to get some sort of better antenna for home use, we rarely transmit there, and at the present moment our antena for reception, is a thin wire wrapped around the the edge of a room a couple of times into a 4:1 balun, which while not a good antenna in all honesty, it works well for picking up some stations, on the MW band (am broadcast.) Which to be honest, due to the location and power of the transmitters one could use a damp piece of string for reception.
I’ve been looking at mag loop antennas, which we have already constructed once before (Hannahs and I’s first antenna project a long time ago.) And it’s worked quite well. So I’d really like to look at that again for home use, as mag loop antennas can reduce the interferance that one receives.
The good thing is, where we do most of our HF work, we have the space, and have set up much better antennas, for a number of bands, so I can really do a good comparison of what works and what doesn’t.
The one thing that did have me a little confused we have a vertical built for the 20 metre band, and when using the kenwood r-2000, I found it was a lot better for picking up the long wave beacons than any of our other antennas. Though we have nothing really for below 80 metres so everything is a comprimise.
~Ivy
A while ago while spinning through the 80 metre band late on saturday night, I came across an AM transmission on 3670Khz, at first I thought it was a net of sorts, but then it started feeling more like a talkback radio show. It also seemed rather dated (I later realised that what I was hearing was a retransmission of an earlier transmission from the 80s).
A few weeks later I found the same station again, and started listening, and discovered it was also been transmitted on 1850kHz too.
The conversations were quite interesting, ranging from technical topics to pure irevrance, then I noticed someone talking that I knew from the radio club i’m a member of (Lionel VK3NM.)
It seems that these ” ‘missions” have been going on since the early 70′s if not even earlier.
more information can be found at http://www.crossbandradio.com/
Anyway last weekend, I joined in, now due to licensing, I couldn’t really call in via 2 metres as it was been retransmitted on 160 metres and untill my advanced licensing comes through I can’t operate there. So I called in via skype, and ended up in a confernce between VK3ASE, VK3NM and myself..
Alot of fun.
~Ivy
Well last weekend Hannah and myself went to Amateur Radio Victorias trash and treasure sale. Hannah found a really nice antenna tuner.
I found though a Kenwood R-2000 I’d seen one of these at the GREC Hamfest earlier in the year, and quite liked it, but the asking price was just a little too much then.
It’s a receiver that covers 150kHz to 30MHz (though the dial can go down to 100 kHz) and has AM, FM, SSB, and CW modes.
The first thing I tuned to was 3LO (774kHz) and I was struck by this radios sound quality. It was pretty much all through the bands, though as it only has a 50Hz tuning step, ssb transmissions can be a little hard to tune in so that the voice sounds natural.
But through the HF broadcast bands, again AM sounded wonderful, even with the narrow AM filter, and I found it did a much better job of receiving AM transmisions, compared with the ICOM 706mkIIG. It may be just that the R-2000 was designed for reception.
I am just struck by the “warmness” of the sound.
I am looking forward to seeing how well it goes for listening in on the 160m AM nets that are on most mornings, and the crossband “missions” That are on on Saturday nights. The only issue is most of the time I’m outside of the city, and it appears that the ground wave for 160m is only about 50 Kms, but at least it is also transmitted on 80m.
~Ivy
After having some luck with simply putting scrap metal into the air as a vertical antenna at 14MHz, we decided to try and do things properly. A trip to the local hardware store has proven quite useful for sourcing antenna elements. 3 metre lengths of 10mm aluminium tubing came out to only AU$8 or so. Of course, it aluminium tubing can be sourced more cheaply (especially as scrap), but this was more convenient for simple experiments.
It seemed like the biggest drawback to our previous verticals was the height above ground. Our copper gas pipe experiment had the base of the antenna only 3 metres above the ground, with the radials lazily laying on nearby objects.
This time, we decided to utilise our EMDRC 9 metre collapsable mast. We had decided to use PVC water piping as the mount system. Unfortunately we never bothered to collapse the mast and measure the outer diameter of the upper section, and ended up buying pipe which was too wide, and possibly too thin-walled. With a bit of persitance and trying again to get the holes to match up with the screws (how do you properly measure straight lines on a cylinder?), we had about 5 metres of aluminium in three telescoping segments on PVC. For the radial system we used self tapping screws to attach a 5cm wide alu strap around the PVC below the vertical element, with one larger hole for attaching an SO-239 socket. The centre conductor of the SO-239 is attached to a short jump lead with a terminal plug around the mount screw at the base of the vertial element.
20m vertical test on ground
Detail of vertical element and radial mount
Mounted vertical ready to raise. Dipole mount for 80/40 below.
Raising 9metre mast with 20m vertical
It began to get dark by the time everything was constructed and roughly tuned. Turns out we had mixed up some of the radials and guy wires, which wrapped around each other at the top. Not expecting good results the first on the first try, I was surprised to find it gave little to no reactive loading at resonance, which was around 13.9MHz. The resistive load of the antenna was much higher than expected, at nearly 200 Ohms. I had read the angle of radials to vertical element can change the Zo of the system, but had no time to try at the time.
Coming back to it, and getting the radials as close to 45 degrees from vertical as possible gave good results. We were able to get the Zo down to a good-enough match of 60 Ohms across the lower section of the 20 metre amateur band. the 2:1 bandwidth was across any usable frequency for amateur use.
The 1964 ARRL Antenna Handbook gives ideas for multi-band verticals containing multiple resonant vertical elements with 4 resonant radials for each band. This PVC mounted system may lend itself well to this setup, just in time for the growing 10 metre openings.
de VK3GNU. 73