04-11-14 14:46 Roy Witt wrote to Ed Vance about Resurrected   
      
    RW> @MSGID: <53491801.306.amtradio@capcity2.synchro.net>   
    RW> Greetings Ed!   
   Howdy!, Roy,   
   -snip-   
    EV> I didn't investigate anything else on that web site and didn't know   
    EV> about their request for support was for more than Photos and   
    EV> Schematics of Old Radios.   
      
    RW> Well, there are 3 schematics for that radio on that site. I'd   
    RW> like to have a copy of them, but the radio has a schematic   
    RW> attached to the inside of the back cover and it's readable,   
    RW> with a magnifying glass.   
      
   I haven't been back to that site, but anything I see that I want to   
   keep a copy of I use DoPDF to 'print' a .PDF of it.   
   If they show a schematic try DoPDF or even use the Print Scr key and   
   use some program like Irfanview to Paste the Clipboard into, and then   
   just remove the extra stuff to save the schematic as a .JPG .   
   HTH   
   -snip-   
    EV> I don't think I even had heard of a Log Periodic Antenna in the early   
    EV> to mid 1960's.   
      
    RW> Ummmm. They were on every rooftop of houses with a TV set. Most   
    RW> of them were dual banders, aka VHF and UHF...when I worked for   
    RW> Solar Turbines in San Diego c1967, a younger friend and I built   
    RW> a few for our own use. He was a tool & die apprentice, I was   
    RW> t&d journeyman at the time and he lived two blocks down the   
    RW> street from me.   
      
   I only remember seeing Yagi TV antennas on houses, mostly VHF only,   
   though sometime later I seen a UHF over a VHF antenna.   
   -snip-   
    EV> And it would be a bear to make and position by the TV Set.   
      
    RW> There's a video on YouTube showing how to make one out of   
    RW> stripped RG59 coax (using the shield only) as the electrical   
    RW> 'boom' and #12 house wire as the radials. It is only 58cm   
    RW> (22.6") long. The support boom is made out of wood, 1" square,   
    RW> and all radials are wood screwed to the coax boom at a   
    RW> specified spacing.  Crude, but affective. The video shows the   
    RW> builder holding the antenna pointing it out of the window,   
    RW> waving it about, the TV HD signal fades and brightens as he   
    RW> finds the station's xmitter site.   
      
   Thanks!, but that rig would be cumbersome to use IN a bedroom.   
   My Twin-Lead Folded Dipole was replaced by a Circular Wire antenna   
   after other UHF TV Stations came on the air.   
      
   The antenna I made just drooped behind the TV Set, the newer one could   
   be turned to adjust for the best picture, and was nicer looking to the   
   older folks.   
   -snip-   
    EV> Tonight I looked at a ruler and that seems about the length that I   
    EV> recall the antenna being.   
      
    EV> My 19 CM guess earlier was way off the mark, wasn't it? .... ..   
      
    RW> Yes, it should have been about 19 1/4 inches.   
      
   Half of that for the 'half-wave' folded dipole I made.   
      
    EV> I do the best I can with what I got, but when I really want to know   
    EV> something I go to the Books I have to get it down to the nitty   
    EV> gritty.   
      
    RW> I keep a formula in my head that allows me to figure a 1/4 wave   
    RW> antenna. Multiplying that by 4 and you get the full wave   
    RW> length.   
      
   See above.   
      
    RW> 2808/freq in MHz * 4 = a full wavelength.   
      
    RW> 2808/582 = 4.825 x 4 = 19.24"   
      
    RW> Somebody asked me some years ago in the HAM echo where I got   
    RW> that 2808 number. Which had something to do with figuring the   
    RW> length of a dipole and a number around 5600. It's been so long   
    RW> since I figured that, I have forgotten what it was.  Anyway,   
    RW> building 1/4 wave GPs that 2808 number worked out very well, as   
    RW> each one of those antennas made for 450 MHz, had less than   
    RW> 1.2:1 VSWR across the entire 10MHz of that band. As would be   
    RW> expected, the 145Mhz and 220Mhz antennas worked just as well.   
      
   The only Antenna Formula I think I can remember was either 468 or 486   
   over the Wavelength (or Frequency) = Frequency (or Wavelength).   
   Haven't made any antennas for years and I'd have to go look at the book   
   first before I'd cut any 14 AWG Copper Wire.   
      
   (Later) I just wasted a lot of time looking around on Wikipedia for the   
   correct number, I looked at Antenna, 486, 468 and did some other   
   searches there and gave up.   
      
   None of the books I have in the room where this computer is were able   
   to help me either.   
   I 'thought' the "The Great International Math On Keys Book" that was   
   included with the Texas Instruments TI-30 Calculator I got in the   
   1970's would have it for me, or another Scientific Calculator I have   
   that had a book with it, but NO, nothing I looked at showed me what I   
   was trying to find.   
      
   So I went and got a Handbook to see the number is 468, but my idea of   
   the Formula it was used in was all wrong.   
      
   Length of Half-Wave Antenna (feet) = 468 Divided By   
   Frequency in Megacycles.   
      
   DUH!!!!!!   
   -snip-   
    EV> I ran a wire around my radio room up near the ceiling, One Big Loop.   
    EV> I used  it with the DX-40 on 20 Meters.   
      
    RW> Not for transmitting I hope.   
      
   SURE!, what else do you use a Heath DX-40 for?   
   -snip-   
    RW> Not only that, but the radio was xtal controlled xmit only. It   
    RW> had a tunable receiver. That was nice for listening to off   
    RW> frequency radios. My Golden Eagle had that too, but it could   
    RW> switch to a set of 23ch mixer controlled receiver too.   
      
   My DX-40 was Crystal Controlled (Only) until I got my General Ticket   
   and used a Knight-Kit VFO with it.   
      
   CB Radios HAD to be Crystal Controlled until (I think) until the   
   Phase Lock Loop circuit was used in them.   
      
   I don't know nuttin about PLL, but I'd think they have One or Two   
   Crystals in the circuit???   
   There's lots of other things I never figured out how they work, such as   
   J-K Flip Flops........   
   SO I guess I'll never become Mr. Know-it-ALL.    .... ..   
      
   A Friend who went to Navy Electronic Technicians School, told me his   
   instructor said not to try to remember all the formulas, just KNOW   
   where the book is that has them in it.   
      
   ... "How to Budget Your Money"  by  I.R.S.   
   --- MultiMail/MS-DOS v0.49   
   --- SBBSecho 2.12-Linux   
    * Origin: telnet & http://cco.ath.cx - Dial-Up: 502-875-8938 (1:2320/105.1)