04-14-14 12:42 Roy Witt wrote to Ed Vance about Resurrected   
      
    RW> @MSGID: <534D0C83.315.amtradio@capcity2.synchro.net>   
    RW> Greetings Ed!   
      
    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.   
      
    EV> I haven't been back to that site, but anything I see that I want to   
    EV> keep a copy of I use DoPDF to 'print' a .PDF of it.   
      
    RW> The problem with that is that you have to become a member   
    RW> before you can get a large enough view of the entire schematic.   
    RW> They display them in partial views only and those aren't big   
    RW> enough to read.   
      
   I hadn't read that far into their restrictions.   
      
   But I'd try using the Mouse Wheel while holding the CTRL key down   
   to see if what they show of the Schematic could be enlarged so you could   
   use the Print Scr key to Save it as I wrote earlier.   
   Or Print it to a .PDF file.   
   Hopefully the image wouldn't be so Pixelated that it wouldn't be of use.   
      
    EV> If they show a schematic try DoPDF or even use the Print Scr key and   
    EV> use some program like Irfanview to Paste the Clipboard into, and then   
    EV> just remove the extra stuff to save the schematic as a .JPG .   
    EV> HTH   
    EV> -snip-   
      
    EV>> I don't think I even had heard of a Log Periodic Antenna in the   
    EV>> early 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 can't remember seeing any before the late 1960s.   
      
   I just remembered I bought a WineGuard TV antenna from my boss when He   
   Retired as Lockmaster at first Lock and Dam I worked at.   
   That was probably 1969 or 1970 but I didn't use it until sometime after   
   1974 when I moved to the city where I could get a TV Signal.   
   That WineGuard TV Antenna had VHF and UHF and now that I think about it,   
   I'd guess it is a Log Periodic Antenna, I never thought of it that way   
   when I first started commenting about LPA TV antenna to You, I apologize   
   for continuing this lenghty discussion about them.   
      
   When I lived in the country a hill blocked TV reception where I lived.   
   Although my neighbor who lived 1/2 mile closer to town could get One VHF   
   Channel, and we'd go there sometimes to watch TV.   
   As I told Bob Klahn, I listened to the first Moon landing on a Radio.   
   -snip-   
    RW> When UHF began, you saw UHF antennas on the same mast as a VHF   
    RW> Yagi.   
      
   I Sure Did!   
      
    RW> Later, they made VHF/UHF antennas all in one.   
      
    RW> The LPAs came along in the late 60s.   
      
    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.   
      
    EV> Thanks!, but that rig would be cumbersome to use IN a bedroom.   
      
    RW> It's less than 20" long and you could always have it floating   
    RW> near the ceiling, once you found the direction of the station   
    RW> you want.   
      
   If there was only One UHF TV Station that would be O.K., but it would   
   be hard to reposition the LPA if other stations were 90-270 Degrees   
   apart.   
      
    EV> My Twin-Lead Folded Dipole was replaced by a Circular Wire antenna   
    EV> after other UHF TV Stations came on the air.   
      
    RW> What were the dimensions of the CW antenna?   
      
   About 10 inches.   
   Radio Shack 2002 catalog on page 157 has a picture of one.   
   They call it a Loop Replacement, number 15-233 and the cost then was   
   $1.99   
      
    EV> The antenna I made just drooped behind the TV Set, the newer one   
    EV> could be turned to adjust for the best picture, and was nicer looking   
    EV> to the older folks. -snip-   
      
    RW> Like rabbit ears...   
      
   Yes, rabbit ears for VHF, Loop (or Bow Tie)for UHF.   
   -snip-   
    EV> None of the books I have in the room where this computer is were able   
    EV> to help me either.   
      
    RW> The ARRL Antenna Handbook (CR-1974) says it best: 'A   
    RW> length/diameter ratio of 10,000 is roughly average for wire   
    RW> antennas.' Known as a factor K in figuring the length of a wire   
    RW> antenna. Length in inches = 5905 x K/frequency in MHz...and   
    RW> they show a chart of the difference along a wire in space and   
    RW> the real thing.   
      
   I brought the Radio Amateurs Handbook upstairs and it says K = 0.95 IIRC.   
   -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.   
      
    EV> SURE!, what else do you use a Heath DX-40 for?   
    EV> -snip-   
      
    RW> So, you lived a dangerous life in a RF environmet, aka a   
    RW> Faraday box...   
      
   I would suppose everyone located near a transmitter site, Amateur,   
   Commercial or Citizens Band is exposed to RF aka a Faraday box?   
   -snip-   
    EV> A Friend who went to Navy Electronic Technicians School, told me his   
    EV> instructor said not to try to remember all the formulas, just KNOW   
    EV> where the book is that has them in it.   
      
    RW> Now that's the best advice one can get. My other favorite was   
    RW> to reply to the 'I want to learn' this or that questions was:   
    RW> go read the book.   
      
   And IF I know of what book they can find the answer, I will tell them   
   which book to read.   
      
   ... Anything that isn't nailed down is a cat toy.   
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