Oksana | How long is lamba/4 for FM TX? As in, would it be feasible to have stylus with metal core? | 09:48 |
---|---|---|
Joerg-Neo900 | ca 45cm | 09:48 |
Joerg-Neo900 | a "stylus antenna" wouldn't improve the FM antenna which is already length of stylus / N900 | 09:49 |
Oksana | 45cm?.. That's a lot. Aka, it would have to be telescopic stylus. Tremendously fragile. | 09:50 |
Oksana | Existing FM antenna is already length of stylus, sounds nice :-) | 09:50 |
Joerg-Neo900 | just though I'd mention it, wasn't a suffestion to run around with a N900 with 45cm "stylus" | 09:50 |
Joerg-Neo900 | suggestion* | 09:51 |
Oksana | What would happen to existing FM TX antenna if stylus was metallic as well? Would it get better or worse? | 09:51 |
Joerg-Neo900 | worse | 09:51 |
Oksana | Yes, running around would not be good... | 09:51 |
Oksana | :Sigh: So stylus can be plastic or wood, but not metal... What about intricate shape, such as, a metallic spring with tiny stylus diameter and stylus length? | 09:52 |
Joerg-Neo900 | you know, *each* antenna is a dipole. You may consider one half of that dipole be "earth" sometimes. In N900 "earth" gets improved when you plug in USB cable. In stylus bay you may improve the "hot" half | 09:53 |
Joerg-Neo900 | ideally do both for optimum antenna | 09:53 |
Joerg-Neo900 | >>metallic spring with tiny stylus diameter<< tricky, it's running in parallel to a stylus length metal strip that forms the primary antenna. *And* the stylus is way closer to "earh" from PCB ground plane | 09:55 |
Joerg-Neo900 | the latter has detrimental effects when you use metal stylus of original shape | 09:56 |
Joerg-Neo900 | *ideally* you'd use a plastic stylus with two metal surfaces, one close to PCB GND and one close to FM antenna strip. Then connect a closed loop dipole antenna tunes to 100MHz to those two | 09:58 |
sixwheeledbeast | Doesn't it use the Mic and Ground lines of the TRRS anyway? | 10:00 |
Oksana | sixwheeledbeast: Only for receiving. | 10:00 |
Oksana | Transmission is done only on internal antenna. | 10:00 |
sixwheeledbeast | ah sorry i missed TX | 10:01 |
Oksana | How long would such a closed loop dipole antenna need to be? | 10:04 |
Joerg-Neo900 | sixwheeledbeast: that's FMRX, not TX | 10:13 |
Joerg-Neo900 | Oksana: tbh I don't know, but "dimensions closed loop dipole 100MHz antenna" should be a good google search string | 10:15 |
Joerg-Neo900 | if I had to guess I'd suggest you start witt 1 Lambda total lenth | 10:17 |
Joerg-Neo900 | 3.028206646465m so lambda/4 isn't 45 but rather 75cm | 10:20 |
Joerg-Neo900 | sorry, no coffe yet | 10:21 |
Joerg-Neo900 | thought "2m band" but that's not 100MHz but quite a bit higher freq | 10:22 |
Joerg-Neo900 | http://www.sengpielaudio.com/Rechner-Radiofrequenz.htm a closed loop is a https://de.wikipedia.org/wiki/Antennentechnik#Halbwellendipol with another L/2 "wire" connecting both ends | 10:39 |
Joerg-Neo900 | hetre you are https://de.wikipedia.org/wiki/Dipolantenne | 10:42 |
Joerg-Neo900 | how about this? ;-D http://www.waniewski.de/MW/Britz/britz_mw_kreuzdipol_6de.htm | 10:47 |
Joerg-Neo900 | note this is MW not FM band | 10:49 |
Joerg-Neo900 | http://www.waniewski.de/MW/Britz/britz_mw_cross_dipole_6en.htm | 10:53 |
Joerg-Neo900 | de->en | 10:53 |
Joerg-Neo900 | pretty much OT but intriguing | 10:53 |
Joerg-Neo900 | and https://en.wikipedia.org/wiki/Dipole_antenna | 10:55 |
Joerg-Neo900 | I clearly prefer https://de.wikipedia.org/wiki/Dipolantenne | 10:56 |
Joerg-Neo900 | for N900 FMT, a 3m wire forming a circle with ~1m diameter would be ideal | 11:00 |
Joerg-Neo900 | FMTX | 11:00 |
n00buser | hey, what's the status of neo900? | 16:23 |
Joerg-Neo900 | ~#neo900 status is https://talk.maemo.org/showpost.php?p=1556735&postcount=3170 | 16:25 |
infobot | Joerg-Neo900: okay | 16:25 |
n00buser | hmmm, good to know | 16:29 |
Joerg-Neo900 | houkime still does layout, but the UG is dead | 16:30 |
Joerg-Neo900 | took 3 times as long as it should, and yet only 50% of needed preorders ever came in and paid only 40% of final amount each, so we reached like 70% to 90% of R&D with 25% of funds and that's it | 16:31 |
n00buser | Joerg-Neo900, so if you get enough funding you will be able to finish the project? | 17:24 |
Generated by irclog2html.py 2.17.0 by Marius Gedminas - find it at https://mg.pov.lt/irclog2html/!