"Homebrew Group"
                     - News and Reports on Meetings

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Would you like to come to the Dural events, but need to use Public Transport, details HERE

    We usually have at least a few project on the "brew", currently (April 09) we are working on a digital RF power meter, a switched attenuator, HV DC probe just to mention a few pieces of test gear. A member is building a "poor mans Spectrum Analyzer" (and doing very nicely too). There are of course our QRP guys working on single IC or even single transistor transceivers (yes, just one transistor/FET for both functions of receive and transmit). Other members always have something else on the go, even if it is just the home PC or audio gear. Switchmode PSU's big and small are always on the agenda. Yes !! we do work on "ham" gear too, 23cm and 10GHz transceivers along with receivers and transmitters for HF and VHF bands. Various HF and VHF antennas are always on the go.

    Like the membership of ARNSW itself, many of our members are also members of other Ham clubs, so there is a bit of overflow "to and fro" when it comes to projects. Another club a few of us belong to is interested in Fox Hunting (the radio kind) so we can help them with antennas and the switched attenuator for their project. Some of our members "in the trade" can often organize bulk purchase of parts for our projects, whilst another member can arrange PCB's at a very reasonable cost.

    When the new shed at Dural is complete we hope to be able to provide some better facilities for members to do some "metal bashing" as the fabrication of chassis and cabinets for projects is often beyond the home workshop, commercial alternatives are often prohibitively expensive.
 

Regular Monthly meetings - ### New meeting location at the QTH of Seppo VK2SMA #####

      Future monthly meetings of the group will be held on the usual second Tuesday of each month at the new venue. Thanks to the generosity of Seppo VK2SMA, the monthly meetings will now be held at his QTH (with a huge built-in double garage) near the junction of Victoria and Concord Rds, RYDE.  Even in the current cold weather it is nice and cozy, lots of tables and chairs, coffee/tea and biscuits (gold coin donation).

     For those coming by train, get off at Meadowbank station, prior to getting there give Seppo a call on 0425 241 973 and he will arrange for someone to pick you up. Perhaps we could "car pool" if a number of us are coming from a similar area.

      We can now look at more practical nights of maybe some "metal bashing", so if you need to do some chassis or panel work, bring it along as Peter VK2EMU will have some metalworking gear and soldering irons available. He is also gathering together some test gear for members use at the new venue (and also perhaps at Dural). With much thanks to the members involved we already have some gear "donated" to the Group, if you have anything "lying around" ( radio or test gear) it would be much appreciated. Later on we could look at actually repairing donated gear but initially we need stuff in a workable condition (minor repairs OK), bit hard to repair something with something that does not work !!. Old or non-functional gear that we can strip for useful parts is certainly welcome, however even though Toni, (Seppo's XYL) has an interest in our hobby "she who shall be obeyed" will take a dim view of us "cluttering" up "her" QTH.

     If you have any radio gear or antennas "surplus to requirements" it would be most welcome to help build up an operating  Homebrew station, however!!! big stuff and antennas by prior arrangement PLEASE!! (see previous comments regarding clutter)

    As usual, by all means bring along or discuss your latest project, quite often there are "freebies" such as pcb's or parts for all to partake of (last month there were some push switches and SMD components). In fact if you need a few BC847's (SMD), 820R (1206 SMD resistors) or a few DPDT "Isostat" type push button switches (just the mechs, you need to mount them and get a button from, say, Altronics) for your project let us know and "we" will bring in a few for you.

Regular Monthly 2m / 80m Net - on the Dural 2m Repeater (147.000MHz) and 3650KHz SSB (new frequency)
      Held on the third Tuesday of each month at 7:30pm, usually with very able net control by John VK2ASU. All welcome to join in for a chin wag and often discussion on technical subjects. It is also an opportunity to pass along any updated info on current events. Usually runs for about an 30mins with some members continuing their contacts after the net shuts down.
     However currently we are trying out an 80m shed directly after the 2m net shuts down. During the summer months this is possibly a bit early for good propagation on 80m, as a result we may give 40m a go. Listen to the 2m net (if you can) or check the above frequency.

Bi-Monthly meetings at Dural
    These meetings are currently (April 09) held in the afternoon of the ARNSW Trash and Treasure days, that is the last sunday of each ODD numbered month (Jan, Mar, May, July, Sept, Nov). We usually have a "show-and Tell" session first where members and visitors can show us what they are currently working on and may need help with.  Then usually follows a chat or demonstartion of a particular project.
    Peter VK2EMU vk2emu@wia.org.au is the Group's Co-ordinator, so if you would like to give a talk on a subject or need help with something, then contact him before a meeting or you can always have a chat with him at a meeting.
    Also if you are working or a project or repairing a piece of gear and need some help or a special piece of test gear, contact Peter as through our members we have access to quite a bit of very nice test gear. With suitable notice it can usually be arranged for a meeting.

   By the way, why not come along to the Trash and Treasure events anyway, lots of good gear at good prices and "stuff" to rat parts out of for your projects. BBQ is fired up late in the morning and cold drinks available. See Tim VK2ZTM in the VK2WI shack to check out our transmitting gear and grab a cuppa while you are there.
 

Wyong Field Day - 9am Sunday 8th February 2009 (full details on the CCARC website HERE )
    The ARNSW "Radio Experimenters and Homebrew Group" will again have a display at the Field Day, our tables will be as usual in a central location and under cover.
     Members will display various projects and be there to chat about them, covering our wide range of interest from "DC to daylight".. We are hoping to again have a display of Amateur TV equipment put on by Dave VK2TDN and his mates.
     Drop by and see us, have a natter and meet old friends. It is always very nice to meet the "faces" we chat to on the air, some visitors to the show travel long distances, last year we had visitors from QLD, Vic and as far away as Sth Aust.
     Membership in the Group is FREE to ARNSW members, application forms will be available at our tables. Members attending the show are encouraged to spend a half hour or so helping at the tables so that we all get a chance to check out the equipment on display and the "stuff" in the boot sales area.

    Anyone traveling long distances to the Field Day are encouraged to arrange their accommodation early so as not to be disappointed. Plenty of parking on-site or only a few minutes walk from the station, good "facilities" on site, including toilets, tucker and an ATM. Of course the complimentary tea and biscuits up stairs in the main building.

    If you would like to offer help, offer items for display or enquire about our involvement at the show, please contact Peter VK2EMU the Groups Co-Ordinator HERE

     Sorry, has been a while since an update on the activities of the "Homebrew Group", however here are some details of our recent meeting at Dural, which after the usual Trash and Treasure event in the morning was very well attended.

Here are some of the current projects being constructed by members of the Group.

      Firstly we have Kevin VK2ZKB's "interpretation" of the perennial ARRL "Switched Attenuator". In this one he is using miniature toggle switches and SMD R's along with a connecting stripline to retain the 50ohm impedance and achieve a good frequency response of the unit, I think Mark has checked this one as "flat" up to 500MHz. Also visible are the copper shim boxes around the higher value attenuator sections as we found the incoming signal tended to skip over these as the frequency was increased. This one is built in a "box" made of double sided PCB material, however Kevin has made up some very nice examples of this circuit mounted in "boxes" made up of milled sections of aluminum channel.
    Second we have Mark VK2XOF's project for the front end of an RF power meter, it uses the AD8307 chip (between the blue pots) followed by an Op-Amp to range the chips output. The idea is that we provide a kit for the front end and then users can use an analog meter or a digital meter to read the resultant output. This is a prototype board and the input components around the SMA connector have been hardwired. As it stands the board can measure uWatts to MilliWatts up to the chips rating of 500MHz but can be easily modified for higher powers. This board is ideal to retro-fit into an existing analog power meter.
    Last but not least we have Pascal VK2IHL's beacon controller, similar to the ones actually used on the VK2WI site. It is microprocessor controlled with a front panel display and mode selection. Pascal builds some nice gear and this controller is no exception. He also made his own PCB's with an interesting process of "painting" the copper with matt black spray paint, then using a pen plotter fitted with a scriber to "scratch" off the paint (where he did not want copper) and then etch the board in the usual way through the "mask" formed by the remaining paint. Normal paint thinners and gentle use of steel wool were then used to clean up the board before a spray of PCB lacquer to protect the copper and make soldering easier. This method certainly produced a very neat board.
      On the right are two "well known identities" (Mark and Peter) checking out the "freebies" pile at the mornings Trash and Treasure event. After the meeting  Peter "conned" the able bodied members into helping Tim VK2ZTM roll the new water tank from down the back of the property to beside the new shed, as you can see there is no shortage of "supervisors".

      Then Peter (our Election Returning Officer) got those remaining (and not actually Election nominees) to "stuff" envelopes with all the voting information which he later posted to all WIA(NSW)/ARNSW members.

        All in all, a very good day and we are certainly looking forward to utilizing the new shed when it is finished. We also enjoyed the BBQ put on by Beth VK2AO and friend during the morning and for lunch. Tim VK2ZTM "manned" the VK2WI shack and showed visitors around the stations equipment. Our station engineer Mark VK2XOF, modifies and builds some great equipment, we enjoy checking it out for ideas.

Note: the "happy-snaps" are courtesy of John VK2ASU, thanks.
 

Wyong Field Day - 9am Sunday 8th February 2009 (full details on the CCARC website HERE )
    The ARNSW "Radio Experimenters and Homebrew Group" will again have a display at the Field Day, our tables will be as usual in a central location and under cover.
     Members will display various projects and be there to chat about them, covering our wide range of interest from "DC to daylight".. We are hoping to again have a display of Amateur TV equipment put on by Dave VK2TDN and his mates.
     Drop by and see us, have a natter and meet old friends. It is always very nice to meet the "faces" we chat to on the air, some visitors to the show travel long distances, last year we had visitors from QLD, Vic and as far away as Sth Aust.
     Membership in the Group is FREE to ARNSW members, application forms will be available at our tables. Members attending the show are encouraged to spend a half hour or so helping at the tables so that we all get a chance to check out the equipment on display and the "stuff" in the boot sales area.

    Anyone traveling long distances to the Field Day are encouraged to arrange their accommodation early so as not to be disappointed. Plenty of parking on-site or only a few minutes walk from the station, good "facilities" on site, including toilets, tucker and an ATM. Of course the complimentary tea and biscuits up stairs in the main building.

    If you would like to offer help, offer items for display or enquire about our involvement at the show, please contact Peter VK2EMU the Groups Co-Ordinator HERE
 

    A magic day at Dural last Sunday, initially a little quiet, possibly due to the rain and hail storms on Saturday. Be good when the "shed" is up and running so that events are not so dependant on the local weather.
    A number of boot sales added to the interest in the Trash and Treasure, in fact a little later in the morning a whole trailer load of "stuff" was off loaded onto the grass for everyone to pick at, did not take long for most of it to disappear into peoples cars. Looks like Mark VK2XOF sold the last of the advertised items for the Disposals Sale with a number of purchasers happily carrying away their "new" gear.
    In the meantime Beth VK2AO and friend tended the BBQ which did a roaring trade. A few of us snuck into the shack on the pretext of getting a cuppa to take advantage of the air conditioning.
    Un-known to most of us, one of our regular members has a serious interest in Electric Cars (no not toys, the ones you drive on the road) and displayed his latest project, an all electric conversion of a small commercial van (more about this later).

     After an extra sausage-ina-sanger from the BBQ we got the "Homebrew" meeting under way, by general consensus in the shack with the air conditioning.
     First up for the show and tell section was our friend with his Electric Car, he covered considerable detail on the conversion and equipping of his vehicle, which he now drives to work on a daily basis. The vehicle was displayed at the recent Electric Car Show in the Western Suburbs, which in turn was the subject of a very good article in the latest Silicon Chip magazine.
    Next up we had Peter VK2TPM with a beaut thumbwheel controlled DDS signal generator followed by Brian VK2TOX showing his "under construction" homebrew valve tester (basically a jiffy box with a few valve sockets and patch plugs) the metering and power were to be provided from other projects. This prompted Mark VK2XOF to mention problems with commercial valve testers and the tendency for a valve under test to actually oscillate and produce all sorts of strange test results. He detailed some methods of wiring and the use of ferrite beads to overcome or at least minimize the problems.
   Then came Stephen VK2BLQ's demo of a number of valve related projects, their use and construction. He also mentioned some information on recovering components from old radio/TV chassis. He presented a circuit from an old issue of Practical Wireless magazine of a two valve HF transceiver.
    All the time John VK2ASU is busily videoing the proceedings. Much discussion continued after the actual meeting. Peter VK2EMU reminded members of the upcoming Tuesday night meeting at Seppo's place which will start a little early to allow for a bit of a holiday get-together.
 

     We had a great meeting at the new venue, nice and warm on the very cold night. Good turn-up with all the usual faces along with a couple of new ones, including a gent who played us his rendition of "Australia Fair" on his harmonica in celebration of his 60th year as an Ozzy citizen, apparently "back in the day" he actually helped build the shack at Dural.
    John VKASU and myself dropped by Maccas at Nth Parramatta around 6:30 to 7pm just to make sure that no one had missed the announcement of the new venue.
    Dave VK2TDN (a returning member) was there and discussing various microwave gear, one of the guys set up a wireless video and monitor so that all could see the equipment being demonstrated. Myself and a number of others discussed various AD chips and their use in RF Wattmeters, we have found a good 100W microwave 50ohm dummy load chip and a log to linear converted chip as very reasonable prices, these could form the basis of a very compact microwave power meter.
     One of our members kindly loaned the Group a 40MHz CRO for the members use and Peter VK2EMU has gathered some test gear which he has loaned to the Group also.
     A member brought in some Xtals and components and some hardware as "freebies" for members.
    Seppo and his XYL set up the place nicely with tables and chairs, along with tea/coffee facilities and biscuits (gold coin donation towards costs)
     Here is a photo (courtesy John VK2ASU) of the meeting, behind the camera position is a nice little workshop area.
     We are looking forward to future meetings and getting stuck into some practical stuff, as nice to now have somewhere we can let a bit of "soldersmoke" out.
 

     Although rather overcast we had a good day, well attended and thanks to all who came, those who did not, perhaps we will see you next time.
     Our "Technical" meeting started off with Erik VK2MAN giving a very interesting demo of Wifi and it's uses for Ham Radio, included were various antennas, networked transceivers  and operating software. This was followed by Peter VK2EMU continuing the theme with more info on microwave waveguides and antennas, with special attention to "homebrew" antennas for 2.4 and 5.6 GHz operation, all made out of readily available materials. he also drew our attention to a QST article on a printed circuit board tri-band antenna for our microwave bands but only to be used on low power. the article showed what happened when someone applied 200W to the PCB antenna (it let all the smoke out of the PCB).
     Following this was our "show and tell" section of the meeting with Mike VK2BMR demonstrating his PIC controlled RF Power Meter which contained two separate "front ends" allowing measurements out to 3GHz using AD converters to give a linear digital readout. Ross VK2VVV then showed us his homebrew "squid pole" collapsible field antennas, one of Max VK2AFE's friends then showed us his version of a field antenna utilizing a work light stand and a sectioned "tower" to support various HF whips.
    OOPs! nearly forgot Bernie showed us his latest high power HF ATU built up for a friend who is "into" portable military gear and needed an ATU with the same footprint as his "man portable" gear. All in a nice rugged homebrew aluminum box built from square bar frame and sheets sections.
    Along the way various members and visitors contributed their ideas on the equipment being demonstrated, this was followed by Mark VK2XOF mentioning the upcoming ARNSW Disposal Sale of Deceased estate equipment. keep an eye on the front page of this site for details in a week or so. Peter VK2EMU then mentioned a proposed alternate meeting place for our "Tuesday Night" meeting, details in a few days.
    Fortunately the rain held off till we were leaving. By the way the meeting was preceded by an excellent Trash and Treasure and Boot Sales in the morning.
 

     A great day, well attended and thanks to all who came, those who did not, perhaps we will see you next time.

     Peter VK2EMU kicked off the meeting with the show-n-tell section, where Mark VK2XOF "introduced" us to the new Dural 23cm Beacon Unit he is currently building, this encouraged much discussion on microwave construction and cabling of signals.
    Graham VK2GRA showed us his "flexible antennas" made out of lengths of retractable measuring tape, he is working on a variation with laminated sections similar to Military manpack radio antennas. He also mentioned a web link to a US Military Antenna manual he had located in the public domain (email vk2tox@wia.org.au if you would like details).
    Peter VK2TPM showed us his variation of the Drew VK3XU's RF Inductance meter and detailed it's use in his experiments with RF Filters, he also showed us his latest project a AD9851 DDS chip controlled by an 8 pin AVR microcontroller.
   Peter VK2EMU detailed his trials in getting 28/40 pin daughter boards working for the PIC Programmer he built recently (a Silicon Chip Mag project) and that he had found good results with the "WinPIC" software recommended for the newer project in last months SC.
     In between making us all movie stars (he was videoing the proceedings), John VK2ASU showed us his latest HF receiver project utilizing an MC3361 all-in-one chip but most interestingly he has mounted the project on the remains of the innards of an old digital clock and used the existing tuning cap and dial drive mechanism/pointer to obtain a vernier drive for the cap. He also had a "crystal lattice filtered superhet" project using the same chip and CB xtals (used at their fundamental freq of around 9MHz) for the LO, the VFO used a 5.5MHz ceramic resonator. Just to top it off he also showed us an AM (Broadcast band) killer filter based on an item in the 2000 ARRL Handbook.
    Then Stephen VK2BLQ showed us his "HRO" solid state receiver, so named because it utilized the dial and a section of the tuning gang out of an old HRO radio set. This receiver although built into a nice "period" wooden case with antique knobs etc was definatly "state of the art" solid state, even including provision for DRM reception. For the "techos" amongst us, it is a 80-40m receiver using the HRO VFO mixed with 24MHz xtal oscillator to produce 28MHz, then either divide by 4 (40M) or 8 (80m) through a Taylor mixer plus an audio phase shift network to remove the images. Along with is beaut set was an external speaker built into a very "retro" wooden case. Great stuff Stephen, amazing what you can do in the packaging department with some chipboard, a router and layers of varnish. Stephen also brought along a homebrew QRP RF Power meter which Mark checked out later.
     Alan VK2ZAY was very quiet although I did notice he had Mark check out his tiny RF Power meter adapter later in the happenings.

Well !! then we got to the serious part of the meeting.

    Peter VK2EMU introduced us to the "Technical" part of the meeting by detailing the basics of RF loads and metering. Mark VK2XOF having set up a HF Transceiver and measuring equipment proceeded to test and check the calibration of members power meters, dummy loads and VSWR equipment. During all this peter passed around an opened up commercial VSWR meter for people to see the construction details of the sampling head in the meter. In the process "we" discovered something wrong with Peter's you beaut Bird RF Dummy Load, luckily Mark had another one so things continued, we then moved on to VHF and microwave equipment. A few guys brought in homebrew power meters and dummy loads which were also tested, we also checked out the HF and VHF response of various CB type VSWR meters. The ones using micro strip construction were surprisingly useful at 2m.

    While all this was going on a few smaller groups started up their own discussion of various matters. Les VK2KYJ detailed a range of carbon resistors he had found in which a range of values between 150 and 250 ohms were 1:1 VSWR to past 1GHZ, this let to a discussion on the merits of SMD and "leaded: resistors with regards usefulness at RF. Another group were discussing front ends for PIC based frequency counters, yet another were planning some PCB photo etching, another on AVR programming. All the while Erik VK2MAN had a laptop and a GPS receiver set up and displaying local maps and GPS information.

    OH!! by the way both Alan VK2ZAY and Peter VK2TPM both run excellent websites/blogs of their own with lots of useful info and projects. Check HERE for details.

    Don't know how we get through so much stuff in such a short period of time, but we do, so as usual a very interesting meeting and certainly something for everyone, see you next time, either at Dural or at or Macca's meeting.

NOTE: will post a few photos next week when John loads his video onto a CD.
 

      Great weather at Dural last Sunday and a very informative talk by Mark VK2TOX on Switch Mode Power Supplies of the sort normally seen in Ham shacks. He also covered "SAFE" testing and servicing of this equipment. Much discussion from the floor on various aspects of this subject including component ratings, circuit layouts and personal experiences of those attending.

     Followed by an interesting show-n-tell session where peter VK2EMU showed us his latest project a solid state variable high voltage supply (see the 5th Jan update for a the "work in progress" version), Alan VK2ZAY had some postage stamp sized new circuits he was trying out.  Peter VK2TPM brought along his latest DDS project, a kit from the US which generates 0 to 60MHz and uses a magic little joy-stick control to select and change the menu items shown on the inbuilt LCD display. Your scribe brought along a QRP Power Meter (meter head only) he "picked-up" at Wyong and described his plans to build a small dummy load (also "picked-up" at Wyong) into the box in time for our next meeting where he hopes to check its calibration. Mike VK2KPM is in the process of building up a "Soft-Rock" transceiver kit from the US, hopefully he will have it ready for a demo at our next meeting.
 

     A very good turn up with some new visitors and a good active meeting. Enthusiastic chat amongst members and visitors on their latest projects. Alan VK2ZAY and John VK2ASU chatted about Alan's latest 30m Autodyne receiver whilst your scribe used his laptop to show the video from Alan's website www.vk2zay.net  on the project.  Mark VK2XOF helped a group of guys examining a vintage vale chassis that one of the members is renovating. Peter VK2EMU brought in his latest project, a solid state variable HV PSU (0 to 350VDC) very nicely "boxed" up in a recycled PC case. Sorry Peter, I took the photo before you got all your tools out of the enclosure.
        Stephen VK2BLQ in another group were discussing various digital circuits including an interesting RF generator using a HC4046 VCO chip. A visitor John VK2WEO brought in his version of the recent "AR" metal bender. The bender was examined in detail as most of us are or are planning to build some version of this very handy project.


     Peter then had a chat with us on arrangements for our display at Wyong, by then it was about time to call it a night and head home.
 

     I guess the Holiday season kept the numbers down a bit earlier in the day, but a good day weather wise, lots of interesting "stuff" looking for good homes.
     Because of the smaller numbers we kicked off the Homebrew meeting a bit earlier than normal (around 12:30) with visitors introducing themselves and members showing off their latest projects. We had by then adjourned to the air conditioned comfort of the VK2WI shack. Then followed an excellent demonstration by Stephen VK2BLQ on his "DRM" converter (details in the next edition of the Newsletter) connected between the natty Jaycar AM/FM receiver (with the IF output) and his PC loaded up with "Dream" software package. He had a number of pre-recorder HF sessions on his PC which he used to demonstrate the application. Plenty of interest shown by all who attended, members added their own experiences to the demo, including suggestions on alternate frequencies on which they had heard DRM transmissions.. Before and after the demo we had a number of discussions on subjects ranging from electronic brake testing through to antennas.