All Things Wireless & Letterpress

All Things Wireless & Letterpress

Saturday, November 16, 2013

Rush to Meet the Sked!!

I am sure you have found yourself in a rush before.  Eight hours to move a mountain, and you have to start from scratch, and you haven't even begun yet.  And such it was last night for my very first on the air 'schedule', or "Sked" in radio vernacular.  The folks from the local vintage radio group, "Florida Boatanchors" had decided to meet on the 40 meter band, many of you remember it being called the "Short Waves".  Amateur Radio Stations have privileged air space right there with the Broadcasters, and have had now for one hundred years.  

The exact frequency is 7290 kHz, on some of your SW receivers, that might look more like 7.290 mHz.  The mode was AM, the traditional voice mode used in radio communication for better part of ninety years, now.  My particular rig can also do AM transmissions, so I decided to participate.  

But alas!  No antenna!  My old wireless station had been dismantled and sold over five years ago, and my leftover antenna 'stuff' lay mouldering in a pile of aluminium and oxidized copper wire and corroded coax.  Fortunately, part of the recent offering gifted to me included 100 feet of coax cable, and a generous assortment of plugs and mounting posts.  I had a lot of soldering to do before the Sked at 10am, Saturday!  It was midnight right now!  

So, first thing I did was haul in the coax, and thread it through the Letterpress Shop.

One hundred feet of tangled coax can be a challenge, especially at midnight.  I had to interleave it back and forth from one end of the shop to the other.  It was raining outside, so all my work had to be conducted inside.

The above photo shows part of my work space, literally, on the feed board of the press!  Also the stool, which served as my coffee cup parking lot during this operation.

My actual 'soldering station' was the top of my washing machine in the utility room.  Here is where I soldered all my connections which included: my coax plug to fit my radio (PL-259-Y, silver plated!), and an assortment of banana plugs.  I also had to strip the coax, peel the shielding, pre-tin the center conductor, and spread the shielding over the "shoulder" of the RG-58-U plug adaptor.  Yeah, all this fancy terminology just to say I had to solder up my transmission line.  Hey!  That's why the FCC tests us! < grin >

Just so you "dyed in the wool" ops know, I am writing this blog toward my former non-technical audience for whom I wrote as a freelance writer for the Electronics Hobby industry.  I know a lot of you may be very new at all this, many of you are old hands at the key.   But I must tell you, whether you are a newbee or a grisled vet, you must agree there is nothing like soldering on pure military grade tinned silver.  Oh, man, the 60/40 solder and flux just nicely.  There!  Ain't that a pretty connector?  I mean, really!

You may have gathered by now that I am a "Plumber's Delight" kind of guy, who uses a lot of PVC in his antenna construction.  This goes way back to my Novice days.  As I poked around my pile of mouldering antenna junk left over from years ago in my back yard, I came across one of my early dipoles, which still had it's PVC center connector!  Wow!  All I had to do was remove the rusted screws, replace them with the posts you see on the ends of the "T" in the above photo, which are actually banana jacks.  The coaxial cable feeds through the bottom, the coax is separated inside the "T" with the braid going out one side through a hole, the center conductor our the other.  These are then screwed into the end posts.  The actual antenna wires have banana plugs soldered on to one end of each length.  These are, in turn, plugged into these end jacks, and wrapped twice around the screw (the phillips head screw you see in the photo), one for each side.  This relieves the wire strain on the insulator, and protects the coax connection to those wires.  The antenna itself is called an "Inverted Vee", which we all used as Novices back in the 1970s.  Very simple, sure-fire antennas!

And here is my operating position.  My TS-430S, power supply and AT-120 antenna matching unit are parked on my Press' feed table.  My coffee cup has found a new parking lot, as you can see.

Ok, so I get to bed at 2am.  Wake up at 8am, wow, only two hours to get the wire attached to the center insulator, get it up on the push-up pole, feed the coax into the shop, and be on the air by ten AM!!  Time to hustle!  And what you see above is the result.  Voila' !  One Inverted Vee!

If you look closely, you can see how I terminated my wires to the ground: a thin aluminium stake, a piece of nylon weed-wacker wire (say that three times real fast!), and a piece of hardwood substituting for what should be a "Dog Bone" insulator.  As kids, we used to use bottle necks from Coke bottles, filing off the sharp edges of the glass.  Each side of this dipole "Vee" antenna is terminated to the ground in this manner.  There is no earth ground used in this installation.  The radios themselves, however, are grounded.

Here is a closer look at the Inverted Vee's center feed insulator.  It is held to the mast with a simple "U" clamp made for antennas, available at Radio Shack and most hardware stores.  The wire is actually thinner gauge than I am comfortable with, it's 24g hook up wire.  But it was all I had on such short notice.  Normally I use 18g stranded copper, tinned every foot or so.  And so this wire will be replaced soon enough.

These are the sum total tools used, apart from the soldering pencil and clamps at the soldering station.  A pair of dykes, a philips head screw driver, a rat tail file to file the PVC a little so the U-clamp would fit around it, a pair of heavy duty scissors, and channel locks.  Oh, yeah, and weed-wacker wire.  Did I say that right?

So, did I make the "Sked"?  Yup.  Exactly at ten AM!  And I was able to tune the antenna, and it performed flawlessly via the AT-120 antenna tuner.  Now, I could cut and trim the antenna wire itself, tuning it exactly to the frequency I want, and not even use the Antenna Tuner, but I like the ability to re-tune this antenna on other bands, something that can only be done with a tuner.  

We all gathered at 7290 kHz, but some of us had weaker signals, so AF4K (Bry) and myself QSY'd - changed frequency - down to 7270, and held our conversation on single sideband, a mode of transmission and reception that is a bit more modern, and much more efficient.  We had great signal levels between our QTH's. (locations in the Q-signal Lexicon).  We just chewed the fat for about an hour, a lovely QSO (conversation, or contact). 

Wireless meets Letterpress here in this instance, by sharing the same space.  The press is still eying the Kenwood rig suspiciously, but I believe a bond of friendship is in future for the Kenwood and the Chandler & Price Letterpress.  Expecially when it comes time to do those incredible vintage QSL cards!!
And now, for more coffee!

Stay tuned!

-de wd4nka ar k

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