Re: Bitx40 vs the antenna beast
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I. too, am warring with the "antenna beast". I live with my parents, and my dad doesn't want me running coax cables out through window panel feed-throughs or drilling holes in the upstairs walls, and the metal-framed windows are designed in such a way as to pinch a feed-through cable made of flat lead.
My solution will be to make a folded dipole, run around the wall just under the ceiling in my bedroom, and made of 300 ohm flat lead (I have 50 feet of the stuff), with the "legs" 20-1/2 feet long each (I have 41 linear feet of wall in my room). I will be using a 6:1 balun to impedance match (50 ohms out from the radio to the 300 ohm antenna), with an automatic antenna tuner (either my Elecraft T1 or one of my old but trusty LDG AT-11 tuners) between the rig and the balun. Probably won't work much past 40 meters, but it's better than nothing at all!
Rich KC8MWG
On Friday, April 28, 2017 6:13 PM, richard kappler <richkappler@...> wrote:
Fred,
You are a gentleman and a scholar, that is exactly the type of guidance I was looking for!
Cheers, Richard W2KAP?
On Apr 28, 2017 6:02 PM, "Dr Fred Hambrecht" < AAR4MI@...> wrote: Use the MFJ to determine where the antenna is resonant. If the frequency is below 7.285 decrease the ?amount of coil and recheck. Conversely if it is resonate above 7.286 you will have to add coil. ? v/r Fred W4JLE ? ? So I'm a new ham (General), as I've said before, and aside from a VHF/UHF HT, the BitX is my first (and presently only) radio. I'm in an apartment, so antenna choices are severely limited. I am currently running my BitX through a MFJ-1622, which is tapped coil 1/4 wave apartment antenna with a 5 foot whip and a counterpoise. ?(? ). I've NEVER been able to hear anything but static on my BitX40, and have done much troubleshooting, finding nothing amiss thus far (on the second one anyway, the first one I built is another story for another day). I took a wafg and figured it to be the antenna, ordered the parts for Jack's antenna analyzer, most of which still aren't here. Impatient as I am, I've sprung for an MFJ-259C antenna analyzer, which arrived about an hour ago, and sure as shootin', my antenna appears to be VERY out of whack.impedance is about 90 ohms, SWR up at 13.5 at freq 7.285. And now the question: Is this most likely the reason I've been able to hear nothing and no one has been able to hear me? Then I, of course, have to go OT a bit: Any suggestions as to how to adjust this antenna to something reasonable? Near as I can figure, it has three mechanical adjustments: placement of tap on coil, whip length, counterpoise length. I will, of course, spend the weekend adjusting everything, one thing at a time, small adjustments, until I figure it out, but if anyone has the antenna knowledge to give me a little guidance, it would sure save some time. If it's not the antenna, you'll be hearing from me. I've been trying to get on HF for about 2 months now. I've got me an itch that demands scratching! -- In any given circuit, the most expensive part will always sacrifice itself to protect the fuse.
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