|
Super Broomstick....Any good?
Has anyone tried the new super broomstick receiving antenna for sale on
ebay? I was wondering if it was any good or not. |
Probably because he is a new ham, memorized the question pool and has no
idea what a soldering iron looks like or the difference between TV coax and 75 ohm coax is? "Nic. Santean" wrote in message news:3f2a86d3@shknews01... Why don't you build one by yourself ? Nic. "Bill" wrote in message .. . Has anyone tried the new super broomstick receiving antenna for sale on ebay? I was wondering if it was any good or not. |
"J T" wrote in message
... Probably because he is a new ham, memorized the question pool and has no idea what a soldering iron looks like or the difference between TV coax and 75 ohm coax is? OK, let me get this straight.... It's a good thing to make fun and belittle a newbie who is trying to learn something? It's the new ham's fault that the current question pool is too easy for your liking? No one without experience should become a ham? (not sure how one gains experience, but hey, I guess that's not important) Paul AB0SI (an extra light who never used a soldering iron until licensed nor did I know anything about coax until I studied for the exams) |
=2D----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1 This is a little bit off the original topic, but I have a question. Given two unmarked pieces of coax, how do you determine if they're "50 ohm" or "75 ohm" or whatever? Shorting them doesn't work. Jack. =2D --=20 Jack Twilley jmt at twilley dot org http colon slash slash www dot twilley dot org slash tilde jmt slash =2D----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.2 (FreeBSD) iD8DBQE/L/u3GPFSfAB/ezgRAv8RAKCjvWi82W7pp0j8o+i3/74JF533mwCeIiFo zlXqaNMmkpeFhpNmkQumsgQ=3D =3D6bAh =2D----END PGP SIGNATURE----- |
Use an antenna analyzer!
At 1/8 wavelength, from either a short or an open, the input impedance will be purely resistive. The resistive value is the Zo of the line. DD, W1MCE Jack Twilley wrote: -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 This is a little bit off the original topic, but I have a question. Given two unmarked pieces of coax, how do you determine if they're "50 ohm" or "75 ohm" or whatever? Shorting them doesn't work. Jack. - -- Jack Twilley jmt at twilley dot org http colon slash slash www dot twilley dot org slash tilde jmt slash -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.2 (FreeBSD) iD8DBQE/L/u3GPFSfAB/ezgRAv8RAKCjvWi82W7pp0j8o+i3/74JF533mwCeIiFo zlXqaNMmkpeFhpNmkQumsgQ= =6bAh -----END PGP SIGNATURE----- |
=2D----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1 "Dave" =3D=3D Dave Shrader writes: Dave Use an antenna analyzer! Umm, assume that instead of an antenna analyzer, I've got a VOM. Dave At 1/8 wavelength, from either a short or an open, the input Dave impedance will be purely resistive. The resistive value is the Dave Zo of the line. Without being able to send a signal, I won't be able to test it? Jack. =2D --=20 Jack Twilley jmt at twilley dot org http colon slash slash www dot twilley dot org slash tilde jmt slash =2D----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.2 (FreeBSD) iD8DBQE/MAv0GPFSfAB/ezgRAnSGAJ9qX4HHC3vENucos0wEmeZif/llJgCcCyDb BSqxGGB3nUH5l2kU25SJKvU=3D =3DVFX0 =2D----END PGP SIGNATURE----- |
Without any RF test equipment, another way to tell is by physical
measurement of the dielectric and inner conductor diameters. But you'll need some calipers to do that. If you have piece of marked cable of the same outside diameter and either impedance for comparison, you can easily tell the difference -- for the same outside diameter, 75 ohm cable has a noticeably smaller inner conductor than 50 ohm cable. Roy Lewallen, W7EL Jack Twilley wrote: -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 This is a little bit off the original topic, but I have a question. Given two unmarked pieces of coax, how do you determine if they're "50 ohm" or "75 ohm" or whatever? Shorting them doesn't work. |
wrote:
It's a good thing to make fun and belittle a newbie who is trying to learn something? No newbies allowed. The only people allowed are mean old farts suffering from prostate problems. :-) Hint: Treat them like a duck treats a flood. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 80,000 Newsgroups - 16 Different Servers! =----- |
NO! You can't test it with a VOM. You need a signal with wavelength
[frequency] characteristics. Someone in your area should have an MFJ 259B. Ask around. Deacon Dave, W1MCE Jack Twilley wrote: -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 "Dave" == Dave Shrader writes: Dave Use an antenna analyzer! Umm, assume that instead of an antenna analyzer, I've got a VOM. Dave At 1/8 wavelength, from either a short or an open, the input Dave impedance will be purely resistive. The resistive value is the Dave Zo of the line. Without being able to send a signal, I won't be able to test it? Jack. - -- Jack Twilley jmt at twilley dot org http colon slash slash www dot twilley dot org slash tilde jmt slash -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.2 (FreeBSD) iD8DBQE/MAv0GPFSfAB/ezgRAnSGAJ9qX4HHC3vENucos0wEmeZif/llJgCcCyDb BSqxGGB3nUH5l2kU25SJKvU= =VFX0 -----END PGP SIGNATURE----- |
Dave Shrader wrote:
At 1/8 wavelength, from either a short or an open, the input impedance will be purely resistive. The resistive value is the Zo of the line. Don't you mean purely *reactive*, Dave, like 0+jZ0 or 0-jZ0? -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 80,000 Newsgroups - 16 Different Servers! =----- |
Bill wrote:
Has anyone tried the new super broomstick receiving antenna for sale on ebay? I was wondering if it was any good or not. Bill, There are a number of variations on the broomstick antenna. They are all variations on a helically wound antenna (a coil of wire, usually fairly wide spaced, on a broomstick or dowel). In the absence of any other antenna they may or may not work well enough to satisfy you, but you might do just as well or better with a piece of wire strung across the room or hanging out the window. Transmitting is another case -- but you mentioned the 'receiving antenna'. Hope this helps! Irv VE6BP -- -------------------------------------- Diagnosed Type II Diabetes March 5 2001 Beating it with diet and exercise! 297/215/210 (to be revised lower) 58"/43"(!)/44" (already lower too!) -------------------------------------- Visit my HomePage at http://members.shaw.ca/finkirv/ Visit my very special website at http://members.shaw.ca/finkirv4/ Visit my CFSRS/CFIOG ONLINE OLDTIMERS website at http://members.shaw.ca/finkirv5/ -------------------- Irv Finkleman, Grampa/Ex-Navy/Old Fart/Ham Radio VE6BP Calgary, Alberta, Canada |
=2D----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1 "Roy" =3D=3D Roy Lewallen writes: Roy Without any RF test equipment, another way to tell is by physical Roy measurement of the dielectric and inner conductor diameters. But Roy you'll need some calipers to do that. If you have piece of marked Roy cable of the same outside diameter and either impedance for Roy comparison, you can easily tell the difference -- for the same Roy outside diameter, 75 ohm cable has a noticeably smaller inner Roy conductor than 50 ohm cable. This is very helpful. Thanks! Jack. =2D --=20 Jack Twilley jmt at twilley dot org http colon slash slash www dot twilley dot org slash tilde jmt slash =2D----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.2 (FreeBSD) iD8DBQE/MCNoGPFSfAB/ezgRAu4eAJ0UNwB/sUsibeEIIJnNhfb8EzT1yQCfbi6R ZkSckI9I3eJabxJjUDxk84M=3D =3D6cOK =2D----END PGP SIGNATURE----- |
I was actually waiting for someone to catch it but you were too busy
thinking troll or flame. TV Coax is 75ohm. "W5DXP" wrote in message ... wrote: It's a good thing to make fun and belittle a newbie who is trying to learn something? No newbies allowed. The only people allowed are mean old farts suffering from prostate problems. :-) Hint: Treat them like a duck treats a flood. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 80,000 Newsgroups - 16 Different Servers! =----- |
Not necessarily!, there are also "Broomstick " antennas (VHF- UHF type) that
are STACKED sections of coax (Co-linears), where the sheath of a 1/2 wave length piece is soldered to the center conductor of the next 1/2 wave piece of coax (and also vice versa), with several of these sections, done, the last section, if memory serves me right, is a 1/4 wave piece of wire, and it is attached to the last 1/2 wave section, shield, and center conductor shorted together! similar to DB PRODUCTS- Green Hornet, and has a 1/4 wavelength radial for counterpoise. as info, Jim NN7K "Irv Finkleman" wrote in message ... Bill wrote: Has anyone tried the new super broomstick receiving antenna for sale on ebay? I was wondering if it was any good or not. Bill, There are a number of variations on the broomstick antenna. They are all variations on a helically wound antenna (a coil of wire, usually fairly wide spaced, on a broomstick or dowel). In the absence of any other antenna they may or may not work well enough to satisfy you, but you might do just as well or better with a piece of wire strung across the room or hanging out the window. Transmitting is another case -- but you mentioned the 'receiving antenna'. Hope this helps! Irv VE6BP -- |
I was actually waiting for someone to catch it but you were too busy
thinking troll or flame. TV Coax is 75ohm. TV coax has the shield made of aluminum or other nonsolderable material. 75 ohm coax can be soldered :-) |
| All times are GMT +1. The time now is 01:38 AM. |
Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
RadioBanter.com