Monthly update, November

Well its been a little while since the last update and I've been busy. AHARS has been quite active, the good weather has brought about many good events.

The AHARS Symposium. Was a great day, its amazing that as I keep reading and tinkering that little nuggets from the talks start to fall into place. Little bits of wisdom finally making themselves understood. There was just so much to take in on the day... Note the microwave gear on the right hand table, along with the VK5TR loop, and HPSDR rig at the lower right corner.








We had the National Field Day. So I helped out at the AHARS tent. To aid publicity AHARS got a foot in the door of the Eden Hills Primary School Strawberry Fete. Its your usual spring fair; food, plants, books, cloths, stuff, junk, treasure, etc etc...








The great resistor packing day for AHARS. Folks in the club thought it wise to do a bulk purchase of resistors so that all the constructors, repair and homebrew folks had adequate parts in their respective junk boxes. I decided that I needed to stock up too, so I ordered a box. The bulk order was made, around 1.2 million resistors in all. The day finally came, we assembled and sorted out each 'decade', cut 100 of each value, then assembled a bundle of each of the 12 values into a roll, then each roll into a box. Thankfully many extra volunteers participated for a good day. Lots of radio talk. I learned a thing or two about boat anchors. Went home with a box of resistors =)








The AHARS Buy and Sell. I was up very early to help setup for the Buy'n'Sell. There was an amazing array of stuff. Old radio gear, new radio gear, test gear, computer stuff ... I picked up a few things.








With the holidays coming up, I hope to get more done...

73, Kim

National Field Day 2010

Yesterday being the National Field Day - NFD for 2010 in VK (Australia), I spent with the Adelaide Hills Amateur Radio Society.

AHARS setup a tent at the Eden Hills Primary School Strawberry Fair.

A number of contacts was made on HF and 2meters and 70centimeter. Some contacts were made through the cross band repeater on the project horus ballon, launched to coincide with the NFD.

I spoke to about a dozen people across the day and handed out pamphlets. That doesn't sound like many people, but there were at least six club members there across the day, who each spoke to members of the public across the day about Amateur Radio and the club activities.

There were a couple of themes across the day for me. The main one was the grey nomads, who use the travelers nets to update their location and journey progress with their net controllers, mainy for safety, directions and recommended stop overs. Folks who use UHF CB and or the four wheel drive net VKS737 already. It was interesting to see them explore the options that Amateur Radio could give them. Even if it was only a couple of more bands to listen to the various travelers nets and listening to the reports coming in about traffic congestion, etc. Its not something that I've really put a lot of thought into, but certainly created an awareness for me about how folks outside of amateur radio use radio and why.

Secondly was the HF verticals and how to set them up with automatic tuners, especially across multiple bands. I believe the original squid pole article was from VK3JJ in AR, but I will have check that. A few of the AHARS club members present had built up the JJ antenna and all spoke about issues with tuning and assumptions with measurements and materials. There is certainly a lot of room for experimentation and of course careful measurement - a topic that comes up so frequently, which of course lead on to the third theme for me... upgrading my license.

I spoke to several folks about upgrading my license, the study involved and stratagems for learning. All duly noted. I will be pulling my finger out over the summer break.

I bumped into a few old friends, picked up a few books and plants at the fair. Saw a new part of Adelaide that I hadn't seen before. Over all, even with a little sunburn, I enjoyed the day.

73, Kim

The VK5 News: 3rd October

AHARS
Saturday, 23rd October; National Field Day @ Eden Hills Primary School, Strawberry Fair
VK100WIA
Sunday, 7th November; AHARS buy and sell
2nd, 4th Friday; Lunch Blackwood RSL
JOTA 16th
More at; http://www.qsl.net/vk5bar/
VK5KC David

WICEN
9,10th foundation license
23rd October, Nat Field Day
20th, 21st November foundation license training
QRP CW @ Rostrevour Tennis Club
More at; http://www.sa.wicen.org.au/
VK5PH Paul

AREG
Friday 15th October; Meeting at the Reedbeds; Talk on coax cable, types, suitability, tools included
More at; http://www.areg.org.au
VK5BB Ben

Word of the day: flum

flum, v: to move or position an item on a quickly setting glue.

Yesterday I went along to the AHARS symposium. I had a wonderful time. The impact of the event probably won't be fully realised for some time yet. However, I took some notes and a few photos. Also will put together a couple of posts here about the symposium and ideas gleaned from it.

I like to write down words of phrases that I haven't heard before. 'flum' was one such word that I noted yesterday. Thank you to Drew Diamond, VK3XU, for extending my vocabulary. I have more notes to read through and plenty of googling to do =)

73,

Kim, VK5FNET

AHARS Symposium September 19

Event; AHARS Symposium

Topics; Amateur radio, Construction

Speakers; Drew Diamond VK3XU, Phil Harman VK6APH and more

Venue; Belair Community Centre, Corner of Sheoak Road and Burnell Drive, Belair

Cost; $20 at the door for morning tea, lunch and afternoon tea.

Date; 19 September, 2010

Time; 930am - 5pm

80 meter DC Rx - Debugging lack of mixing

Hit the issue with nothing coming out of the mixer. Using the signal injector feeding into the RF input port, I could hear RF static type noises.

So, I spoke to a few folks at the last AHARS meeting. Specifically what drive level from the LO is needed to turn on the 1N4148s. Jim, VK5TR suggests that I will need +7dB. Darryl, VK5JDS suggest about +6dB.

So I made an RF probe, a 10nF capacitor / 1N34 diode / 47M resistor style probe that I attached to the front of the DVM. A simple T shaped arrangement, on a little scrap of copper clad board and put a BNC socket on one end for a CRO probe, the other to a pair of banana plugs to attach to the DVM.

Wonderful; 0.4 volts from the LO. Now to match +7dB up to what volts output that should be...

72,

Kim VK5FNET

80 meter DC Rx step 1 - Diode ring mixer

Decided to take a break from the QRSS Rx. Its doing _something_ but I don't know if its on frequency or if the bandpass filter is obliterating the incoming RF or if my antenna is really crap.

So I hunted around for another project to keep myself busy with in the mean time. Picked up a copy of Practical Wireless, February 2010. George Dobbs G3RJV, has a receiver first built in 1968 that he re-explores. An 80 meter DC Rx.

Thought it might be a simpler project to work my way through. Also if it pans out, would be good to take it along to the AHARS Show and Tell night.

We just had the AHARS Members Buy and Sell night, a week ago and I purchased a handful of T37's and T50's. This will help move along a bunch of projects I have been wanting to do for ages =)

So here is the first step, the diode ring mixer in the middle of the copper clad board...

I think I will put the band pass filter on one side and the oscillator on the other and shield them both. Then add the audio board on another copper clad board. Perhaps build it up in a Haighs tin...?

Kim VK5FNET