That's great, Jim! Let me know how it plays! 73, Charlie, K4OTV When time permits, Charlie, I will do just that! Almost done with everything up to the two boxes with the switchable components - resis
Well, that FO0AAA KAZ terminated loop has pretty good gain as terminated RX loops go, so I wouldn't expect the system to be noise starved, but the gain opf that loop is of the order of -30 dBi at 160
I'd be surprised if a little mismatch between an approx. 100 ohm twisted pair and 50 ohm coax would make any really noticeable difference, but some sort of balun might be in order. For the 40' X 10'
I'm sure that's a good one, Mike. When I built my RX loop, I was busy and In a hurry, and I borrowed one of the old original AMECO tube preamps from my friend, Bill, K4CIA. Worked great on 160,80, 40
As I recall, when I wound the tranformer for my 40' X 10' KAZ terminated loop, I wound it 3:13 T because I was trying to match from 50 ohms up to around 950 ohms. The core I used was binocular that I
Pretty sure it's 73 material, Mike. That's about all I had in my Fair-Rite engineering and designer kits. 73, Charlie, K4OTV --Original Message-- From: Topband [mailto:topband-bounces@contesting.com]
What's taking out the J-310s, Jim? I have some around here somewhere, but it's been years since I've seen them. Did you try Digi-Key? Do you need to modify your preamp a bit to better protect the J-3
That's great, Jim!! Sounds like it's working well!! Have fun! I'm sure you will like it! 73, Charlie, K4OTV From: James Rodenkirch [mailto:rodenkirch_llc@msn.com] Sent: Sunday, August 25, 2013 9:53 A
Jim, If you really have trouble getting some J-310s, let me know. I'd really have to hunt -probably out in my garage. The J-310s that I have, if I could find them, are, I expect, at least 20 years ol
I think you are correct regarding ON-Semi, Andy. I think I might check Digi-Key and see what mfr. they list for the J310. 73, Charlie, K4OTV As far as am aware On-Semi still make the TO-92 J310. Fair
Of course, a 12AT7, or better, a 6DJ8, would be excellent preamps as well, and aren't so sensitive to transients etc. :-) (Showing my age, I guess!) As far as am aware On-Semi still make the TO-92 J3
That's always worked for me, Mike! The bit of resistance that I suggested that Jim add ahead of the FET gate and the diodes serves the same purpose as your incandescent lamp - but I expect that the l
Actually, Jim - for 160 and 80m, where you could tolerate some capacitance, you could even try back-to-back 1 amp rectifiers, like IN4004-1N4007. You surely wouldn't blow those out! :-) I'd probably
Yes, we could swing the grids of those tubes quite a ways before encountering enough non-linearity to produce a significant amount of intermod, Andy! The old original AMECO tunable vacuum -tube pream
Gee, that's really interesting, Andy! I also built a much simpler oscilloscope when I was a teenager and new ham! Yours was a really elaborate and impressive 'scope project! Congrats! Glad to hear fr
Thanks, Andy I understand your IP and trade-secret issues. That's an interesting approach. I'll have to give it some thought, although I don't expect to be building preamps anytime in the foreseeable
Hi, Herb Something you might consider is feeding the paralleled loops via a 4:1 current balun. I used this very successfully on a 2 el 5-band quad (my own design) fed with RG-213 through a 4:1 curren
H I, Herb Well, I expect that your 80/160 delta loop can be made to play well. Do you use EZNEC? It's heck of a lot easier to deal with the interactions with a keyboard and mouse than raising and low
Hi, Herb Something you might consider is feeding the paralleled loops via a 4:1 current balun. I used this very successfully on a 2 el 5-band quad (my own design) fed with RG-213 through a 4:1 curren
Hi, Herb Well, the quad was built in "delta" fashion, and I just brought all the delta drivers together at a common feed-point at the bottom of the driver array. That resulted in Deltas that were som