The AM Forum
March 28, 2024, 01:21:14 PM *
Welcome, Guest. Please login or register.

Login with username, password and session length
 
   Home   Help Calendar Links Staff List Gallery Login Register  
Pages: [1]   Go Down
  Print  
Author Topic: 75 ohm twin lead source  (Read 17858 times)
0 Members and 1 Guest are viewing this topic.
K6JEK
Contributing
Member
*
Offline Offline

Posts: 1189


RF in the shack


« on: August 03, 2005, 08:15:15 PM »

I'm putting up a stealth dipole.  Feeding it with 75 ohm transmitter twin lead sure would be dandy.  This stuff doesn't exist anymore, does it?

Jon
Logged
w3jn
Johnny Novice
Administrator
Member

Offline Offline

Posts: 4620



« Reply #1 on: August 03, 2005, 08:23:45 PM »

Yeh, saw some advertised in either the latest QST or World Radio - or maybe both.

73 John
Logged

FCC:  "The record is devoid of a demonstrated nexus between Morse code proficiency and on-the-air conduct."
Pete, WA2CWA
Moderator
Member

Offline Offline

Posts: 8154


CQ CQ CONTEST


WWW
« Reply #2 on: August 03, 2005, 09:02:37 PM »

Quote from: w3jn
Yeh, saw some advertised in either the latest QST or World Radio - or maybe both.

73 John

You must have better eyes than me. I couldn't find it in either publication. Also checked RadioWorks, DavisRF, Wireman, RF Connection
Logged

Pete, WA2CWA - "A Cluttered Desk is a Sign of Genius"
w3jn
Johnny Novice
Administrator
Member

Offline Offline

Posts: 4620



« Reply #3 on: August 04, 2005, 07:27:13 AM »

It was one of those places that sell wire, premade dipoles, and such.  I think I tossed out the worldradio but I'll check the QST.
Logged

FCC:  "The record is devoid of a demonstrated nexus between Morse code proficiency and on-the-air conduct."
W1GFH
Guest
« Reply #4 on: August 04, 2005, 09:57:52 AM »

Van Gorden carried 72 ohm twinlead last time I checked.

VGE/Van Gorden Engineering
P.O. Box 21305
S. Euclid, OH 44121
216/481-6590
FAX: 216/481-8329

But why not use good olde 300 ohm twinlead?
Logged
K6JEK
Contributing
Member
*
Offline Offline

Posts: 1189


RF in the shack


« Reply #5 on: August 04, 2005, 04:38:55 PM »

Quote from: W1GFH

But why not use good olde 300 ohm twinlead?


That's the back-up plan, Joe.  I just thought it would be fun, light weight and invisible to try the 75 ohm stuff.  This antenna will only be supported at the ends.
Logged
WA1GFZ
Member

Offline Offline

Posts: 11152



« Reply #6 on: August 04, 2005, 05:10:27 PM »

Get a spool of #20 or #22 teflon wire and twist a couple twists per inch and you will be quite close to 75 ohms.
Find some aircraft teflon 1553 transmission line wire 78 ohms and shielded. Some of that stuff is quite light but may be #24 wire
I bet GFH can get some over at APEX
Logged
W1GFH
Guest
« Reply #7 on: August 05, 2005, 09:10:50 PM »

Find some aircraft teflon 1553 transmission line wire 78 ohms and shielded. Some of that stuff is quite light but may be #24 wire
I bet GFH can get some over at APEX

If I knew what it looked like I could. Is it balanced xmsn line?

PS> I hate the new board layout.
Logged
KB2WIG
Contributing
Member
*
Offline Offline

Posts: 4484



« Reply #8 on: August 05, 2005, 10:05:27 PM »

 ..... maybee play with zipcord?? i've used it 'caus the wife thinks it's a n extension cord...... hows about some homemade 75 larder line ..?.. 22ga. enamel with some cheep buttons fer spacers?? If it works, maybe you can sell some on epay                                             as "Vintage" "Ham"  "Radio"                klc         
Logged

What? Me worry?
K1JJ
Contributing
Member
*
Offline Offline

Posts: 8893


"Let's go kayaking, Tommy!" - Yaz


« Reply #9 on: August 05, 2005, 10:50:39 PM »

..... maybee play with zipcord?? i've used it 'caus the wife thinks it's a n extension cord......      klc         

Back in the 60's [paper route money] I used zip cord exclusively for both feedline and dipole flat tops. Single band antennas, not for multiband like openwire... unless you make a fan dipole.

Buy a 500' roll for cheap and use it at its double thickness for the flat top to give a broader swr curve and strength. Twist both ends together like one wire.

The stuff works FB as ~70 ohm? feedline, balanced. Make sure you use a 1:1 balun into the unbalanced 50 ohm rig. I think I wud hesitate to use it above 40M, but who knows... never checked it for loss. Guess PVC plastic covering ain't THAT bad if the line has a reasonable match to the ant.

T
Logged

Use an "AM Courtesy Filter" to limit transmit audio bandwidth  +-4.5 KHz, +-6.0 KHz or +-8.0 KHz when needed.  Easily done in DSP.

Wise Words : "I'm as old as I've ever been... and I'm as young as I'll ever be."

There's nothing like an old dog.
K6JEK
Contributing
Member
*
Offline Offline

Posts: 1189


RF in the shack


« Reply #10 on: August 06, 2005, 12:45:40 PM »

Van Gorden carried 72 ohm twinlead last time I checked.

VGE/Van Gorden Engineering
P.O. Box 21305
S. Euclid, OH 44121
216/481-6590
FAX: 216/481-8329

But why not use good olde 300 ohm twinlead?

I've called this number several times over the last few days.  I get an answering maching that says the message box is full.  Maybe it's vacation time in Ohio.   I'm pretty sure this is the right number.   

I intend to use the 300 Ohm ladder line not any of the other interesting suggestions.  The 300 Ohm stuff has the great merit of  being already in my possession somewhere.
Logged
W1GFH
Guest
« Reply #11 on: August 06, 2005, 12:54:19 PM »


I intend to use the 300 Ohm ladder line not any of the other interesting suggestions.  The 300 Ohm stuff has the great merit of  being already in my possession somewhere.

Don't forget Radio Shack TV Twinlead - it rocks. Light, unobtrusive, cheap.
Logged
Pages: [1]   Go Up
  Print  
 
Jump to:  

AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
 AMfone © 2001-2015
Powered by SMF 1.1.21 | SMF © 2015, Simple Machines
Page created in 0.057 seconds with 19 queries.