Name Changed and Activity

G'day All,

Well, it's official; today I received my AOCP(S) in the mail! So, now I've changed the name and URL of the site to reflect things. 😉

Activity wise I've been busy but haven't had time to upload things to here. My new FSM with the digital voltage panel is complete and working wonderfully so I hope to post up more on that shortly. Today I've also been shopping so that I can build up an interface between my computer and radio to do some digital work with my new license. I'm also still 90% complete on my little 2el 2m beam that I plan to take to tassie with me on the plane.

Now I have my new FSM I want to do some measurements on the beam and then ultimately write it all up to share with you all in case you want to build your own. 😉

So, hopefully soon I'll post up some more on here, but tonight I'm busy again running a local 10m AM net. So if you're free, come and say hello on 29.050MHz at 1930hrs local time.

Cheers, 
VK1HOW.
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Digital Panel Meter

Taken me awhile to post this as the week-end was a bit busy, but none the less…

Last Thursday I had a quick chance to play with the digital volt panel meter I grabbed from Futurlec for my FSM V2. It is hoped by using this I can see a great improvement in sensitivity – as I can set it up to display microvolts (see previous post).

These guys are new to me so first I had to setup a test bed to see if I could even figure out how to use them (regardless of how simple they appeared). Anyway, that was done with a simple voltage divider network to give me something around 100mV – as FSD on these meters is 200mV. Once that was all done and evaluated with my multimeter it was time to hook up the unit.

After a bit of fiddling success was had. As the photos show it’s happily displaying 109.1mV (well, without the decimal point as I’ve not set that up – just requires shorting two pins, but hard to do while holding the camera). Ideally I’d do another test with a voltage divider to give me something in the uV range, however I think I’ll just build the new FSM.

I’ve got everything I need other than another enclosure and a knob for the potentiometer. So, hopefully another trip out to Jaycar this week and maybe I can build it this week-end.

Photo_1Photo_2

The Maximite

I don't normally buy Silicon Chip, but after walking past the current issue a few times this month I decided to grab it. The front cover was what attracted me because it seemed to allude to a computer that you build yourself. You know, like back in the late 70's where it was all the rage.

Well, it turned out that's exactly what it was. The Maximite is a new kit that is available for pre-order from Altronics and will provide you with a 32-bit computer running at 80MHz and bootloading into a BASIC interpreter.

It will have a VGA/composite video connector, keyboard connector, USB, SD/MMC card reader for storage and maybe best of all a 20 pin IO port. The idea being, you can use that IO port to then interface with hardware if you choose. You know, build your own circuits and have them computer controlled.

Anyway, that should be enough to get you appetite up, so follow the links below for more.

Here is the link for some info about the Maximite:

And here is where you can get one:

And here is the PIC it uses:

2el 2m Beam for Plane Travel

Photo

Here is a preview of an antenna I've mostly completed building. Simply put, it's a 2el 2m beam designed such that it's easily transportable on a plane for when I travel. I wanted an antenna for 2m SSB work that I could easily place in my suitcase along side my trusty FT-817ND and some battery power. Further, this would also suit back-packing/hiking/SOTA.

I will provide more photos, but I'm currently experiencing some issues with my primary computer – which also looks after all my photography – so for now one lonely iPhone photo.

Anyway, basically it's a frame made of PVC sections that can be broken down into sections all ~50cm long. Although in the photo you see some orange conduit, that was only for testing and tuning. But the section that fits into the PVC in the photo, is actually made up of two inter connecting 50cm sections to provide a 1m handle that the user can hold in one hand with the mic in the other.

Onto the frame, one simply uses electrical tape to attach the wire elements. The DE is a simple half wave dipole soldered to coax. It has three ferrite sleeves near the join to act as a balun/choke. Further, for strength there is a small piece of ply wood to which each of the three sections (coax, and each leg of the dipole) are cable tied to. The reflector is then one piece of wire (94cm) with a small cable tie right in the middle to mark the centre for alignment when attaching to the frame.

The frame is also such that it allows for easy variation of the polarisation. In the photo it is obviously vertical, but when I was first testing it was horizontal. However just as I finished testing, VK1SV and VK1DSH were heard on FM so after making initial contact I quickly rotated it so that it was vertical. As one would expect, instant improvement of signals was found.

However (when I finish) each T Piece will be permanently glued to at least one section of PVC (with PVC glue) to increase rigidity and strength – more on this when I finish it and take photos.

After tuning the DE (SWR adjustment) I was then able to also do some basic tests with my current Field Strength Meter (FSM). These tests confirmed the beam definitely has F/B characteristics. These tests where then further validated with receive tests while I was talking with VK1SV. He was some ~20km away only on 5W and thereby only coming through at about S5. As a result, I could almost completely block his signal if I turned the beam away from him resulting in about S1. VK1DSH on the other hand was coming through at full scale, however turning the beam also dropped his signal by about 2 S points.

With my new FSM – parts arrived today – I look forward to measuring if there is any gain achieved from having the reflector. I plan to do this simply (thanks to using PVC) by adding and removing the reflector between tests.

Anyway, there you have it. My simple beam that I can take on plane travel with me. Thanks to Andrew (VK1DA) for providing the inspiration. I actually asked if he had any suggestions for such an antenna, and this is where he pointed me. Thanks!!

I'll provide more information for building when I get a chance – probably a couple of weeks away. 😉

P.S. It seems to have a rather large bandwidth – covering the whole 2M band under and SWR of 1.5:1 – thereby allowing it to be used for both SSB and FM.

SUCCESS!! :D

Why all the capitals?? Because I'm very happy and excited.

Today I passed my Regulations and Standard Theory exams!!

Now I wait for the news to say my new license is activated and I can start using it – I guess that'll be early next month, but after almost three years I think I can wait (almost). 🙂

Woohooo!!!

(I got a quite a good mark on both exams, so now I need to again way up whether to return at the next assessment day and look at an Advanced Theory exam…….. but I'm so excited with all the extra thing I can now play with, we'll see….)

Satellite Receiver Requirements – Update

I should have done this earlier in my attempt to understand the bandwidth of APT signals, but for some reason I didn't think I'd find anything. Anyway, I've now searched Wikipedia in a quest to furthering my understanding of the bandwidth requirements of weather satellite APT transmissions.

Wikipedia had a great description of both what is required, why and the effect of insufficient bandwidth. The specific details are here:

Basically, the APT transmissions are apparently 34kHz wide, and if the receiver's bandwidth is too narrow then you can expect over saturation of the lights and darks – exactly what I've been trying to improve the last couple of days (thinking it was an issue with audio level).