modernhistorian
| Joined: | Sat, Apr 7th 2012, 19:22 | Total Topics: | 0 | Roles: | N/A |
| Last Login: | Never | Total Posts: | 0 | Moderates: | N/A |
Latest Topics
| Topic | Created | Posts | Views | Last Activity |
|---|---|---|---|---|
| Does paint affect a Yagi? | Jan 17th, 02:40 | 4 | 313 | on 25/1/13 |
| 50 or 75 ohm reference for analyzer? | Jan 6th, 22:52 | 2 | 305 | on 7/1/13 |
| Using ladder line with Yagi | Jan 2nd, 00:58 | 1 | 336 | on 2/1/13 |
| Two new ham questions about antennas | Dec 9th 2012, 16:56 | 7 | 686 | on 26/12/12 |
Latest Posts
| Topic | Author | Posted On |
|---|---|---|
| Does paint affect a Yagi? | modernhistorian | on 17/1/13 |
| Thanks; I did not know EZNEC would do that. I've covered the feed point with that sticky coax seal, and we live in a dry climate, so that should be OK. I should have mentioned that the antenna is a 3 element 2 meter Yagi. | ||
| Does paint affect a Yagi? | modernhistorian | on 17/1/13 |
| I put up a small Cushcraft Yagi, and it does what I wanted. I'd like to spray paint it with a Rustoleum green to make it less conspicuous among the trees. Would that affect its performance? I would not paint at the feed point, of course, just the mount and elements. | ||
| 50 or 75 ohm reference for analyzer? | modernhistorian | on 6/1/13 |
| I bought an antenna analyzer to scan my dipole's SWR. It can be set for either 50 or 75 ohm reference impedance. The initial line is 50 ohm LMR-400 coax, but that connects to a 4:1 balun, then 300 ohm twin line to the antenna. 300 divided by 4 is 75, so should I use 75 or 50 as the reference? I get significantly different results when changing. Thanks. | ||
| Using ladder line with Yagi | modernhistorian | on 2/1/13 |
| I plan on setting a 2m/70cm antenna (probably a Cushcraft A270-10S or 6S) to access repeaters, but will need to site it about 200 feet from the radio. The antenna, like the radio, uses 50 ohm coax. Could I run 300 or 450 ohm ladder line between the two, with a 4:1 balun on each end, in order to reduce transmission line loss? The antenna farm that I'm aiming for is on the other side of a ridge line. Will I have to get the antenna high enough for me to see the antennas, or can VHF/UHF bend even slightly over the ridge? Thanks. |
||
| Two new ham questions about antennas | modernhistorian | on 25/12/12 |
| I will try trimming the line length slightly to match Z66BKW and I can probably open up the angle to 90-100 degrees. The 300 ohm feedline is actually 75 feet long and connects to a 4:1 balun. My understanding is that the transmission line is a loss factor but not a resonant factor since the impedance is known. Am I wrong here? Regarding the VHF antenna- I measured out to my view site and it is 350 feet from the radio. Is this practical even with a low-loss coax? Could an amplifier be used here? Thanks again and Merry Christmas to all! |
||