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May 1, 2009 - Dayton in 2 weeks!

   Last summer I took the test and upgraded my license to General class.  Before that I have operated third party on HF a few times during contests under the supervision and call of a friend. (Yes, this is legal in the US, it's in part 97, look it up...)  I do have a Yaseu FT-8900 mobile which does 10 meter FM but that's as far into HF as my gear goes.  When I passed my test I decided that I wasn't going to buy any more HF gear until I have built my own transciever.  This was my motivation to get into ham radio, to build things.  Also, I expect this will be much easier starting out in the HF bands then it would on VHF and above.

   Now, nearly a year later I haven't gotten very far.  If you've read my project page about the J-Pole in the tree you know that my wife and I moved last summer.  Besides all the usual work involved in moving (we still have a garage full of packed boxes) this has meant the new responsibility of maintaining two rental homes as well as our own.  I'm certainly not complaining, just explaining why I haven't built my radio yet.  I have however chosen a design which I like from the internet.  If you are interested in building your own radio gear I would suggest checking out the site of SM0VPO.  He has posted quite a few interesting looking projects there including this one which is the transmitter I wish to build.  I'll definately write about it here when I do but I don't know if it is going to be a project page or just a blog entry(s).  I don't intend to post the schematic as that is his work, not mine but I would like to document the construction technique and any alterations I make to the design as I go.

   I do intend to make this a full transciever.  I am going to stick close to the original transmitter design at first but once it is working I hope to swap sections out and gradually build  a more advanced radio.  One thing I intend to do is replace the VFO with a 2 output DDS or PLL VFO and use the second output to control a home built receiver.  I also intend to add relays for swapping out filters for additional bands as well as switching between U/LSB and maybe even AM and CW.

  For now I am going to use a receiver which I already have.  It's an old Heathkit GR-54.  I've also already built a 20 meter dipole which I installed in our attic.  I'll be writing that one up as a project page soon, Aliesha has already taken the pictures. The old GR-54 is probably not going to make my first contacts easy but with the dipole and the GR-54 I have already received hams from Venezuela, Ireland and Italy. The ham in Italy mentioned that he was transmitting with 100 watts. No one else mentioned their power or antennas.  My first goal will be to reach my friend KI8GM who has moved to New Mexico.  He's the one who suggest that I start with 20 meters and so far that has turned out well as the antenna just fits in my attic. Of course, I haven't really attempted to tune it yet as I don't have a transmitter (or one of those fancy analyzers).  For now it's just cut to a little more than textbook length and folded back.

   I don't actually remember where I got the GR-54, it's been a while.  It has a loud AC hum which does not soften when I turn the volume down.  I would think that I blew a filter capacitor but I remember it not doing that when I first had it.  A capacitor would have been most likely to go when I powered it up the first time right?  Nevertheless I intend to recap it in hopes of eleminating the hum.  I've also noticed a little bit of blue glow in the audio amplifier valve.  I don't have much experience with tubes but doesn't this mean the vacuum has gone soft?  Maybe this is the cause.  I will try replacing that as well.  Besides the hum there is a considerable amount of drift in the tuning.  I'm not really sure if this is due to age, the era of the design or the original quality of the design.

    I've found a number of modifications for the GR-54 on the internet involving replacing the RF amp and mixer tubes as well as adding a voltage regulator to the local oscillator among other things.  I haven't found any explanation of what these modifications are meant to gain but I assume that altering the RF amp improves sensativity and I hope that the voltage regulator will lessen the tuning drift.  At first I would be hesitant to modify an old heathkit radio like this as many of them are collectables but I checked on Ebay.  GR-54s are listed quite frequently and on the occasion anyone bids at all they rarely sell for much more than the shipping.  I guess if it was a baseball card it would be one of the common ones that come in every pack but nobody is looking for.  I don't think any of the mods are really that far off for the era the radio comes from anyway. The tubes are all the same body, connector style so I assume they are from around the same time.  I will attempt to stick to older looking components, for example the cylindrical brown bodied resistors as opposed to the newer shiny curved ones.  I also intend to try to hollow out the old electrolytics and hide the modern ones inside their bodies so it appears authentic.  Wouldn't it be great to discover that someone already did that?  Yah, keep dreaming. I'll be writing this project up too or at least posting a gallery.  When I do I don't know if I should include the mod directions or just link to them.  I have seen them on multiple sites so maybe they are just common knowledge now.  The list of mods which I have was compiled by KB2LJJ although at least one of them came from elsewhere.  Maybe I will email him and ask his preference.

   Besides modifying my receiver and building a transmitter I am also interested in building some test equipment.  I am looking at a GDO, another of SM0VP0's designs as well as an HF Signal Generator by ZL2PD.  I'm not sure if I need both but I liked the designs and neither looks like it will be that difficult or expensive.  This is where my original mention of Dayton comes in.  I have decided that this year my main focus at Dayton will be purchasing components.  I have the parts lists all done up in a notebook for each four of these projects.  Currently I am rushing to inventory my junkbox so I can cross off what I don't need.  I seem to make it to Hamvention about every other year.  Each time I bring a fixed amount of money to spend, as much as I enjoy looking at all the pre-built toys and bringing something shiny back that I can turn the knobs on and play with right away my goal is to abstain from that and pick up all the components I need to complete these projects and keep me busy for a while without resorting to EBay where I spend more on the shipping than the part or driving an hour just to find anything better than a RadioShack CellphoneHut.  Of course, I'm sure I'll pick up at least some small toys while I'm there.

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