John,
Very well put. I am the one who asked the loop winding question, and I will certainly post my results when I am finished. After a long hiatus from MW listening, I have gotten back into it over the last year or so with a vengeance thanks to the good people in this group and the purchase of a Tecsun 300, 310 and 380, and I will probably get amother 380 to do a stealth mod once I get the 7.5" transplant done.
I also have a Sony 2010 purchased new in 1992 from Gilfer in New Jersey (remember them?) which has had the Kiwa wide filter and audio mods done, and a rebuilt Hammarlund HQ-180AX, which should outlive me (not that I'm that old, I'm 55) as it is an absolute tank. I am handcuffed as far as antennas go since I have a small yard, so I have a Wellbrook 330s, a Quantum Loop, a CC Crane Twin Coil Ferrite and a Select-a tenna. I also want to try my hand at a PVC loop this summer from Gary DeBock's articles, particularly the 36" collapsible loop. Also, being in Northeast Queens, NY, about 2.5 miles from 50k blowtorches WCBS 880 and WFAN 660 doesnt help, but I do my best.
Again, thanks to John Bryant and all the other wizards in this group.
Barry Gelb
Bayside, NY
toggle quoted message
Show quoted text
--- In ultralightdx@..., "John H. Bryant" <bjohnorcas@...> wrote:
This recent exchange with, primarily, Gary DeBock
in suburban Seattle-Tacoma and Roy Dyball in
Australia helping an Ultralighter who was
beginning his first ferrite rod-coil winding is a
great example of what makes this group so
special.... great positive attitudes and a very
real willingness to help each other over our
personal rough spots. Bravo, guys!!!
Over 25 years ago, when I was getting back into
radio after a 25 year hiatus, Gerry Dexter, who
literally wrote the book on SWBC and MW QSLing
told me "You know, John, it's not the great DX
catches or the QSLs, but rather the many friends
that I've made that really make the hobby great!"
At the time, I was just back in and climbing up
the ladder of SWBC countries QSLed and I said "Yeah, right, Gerry!!!"
Geez, old Gerry was absolutely right! I've made
a passel of new friends here, that I value very
much.... and renewed many old ones, too... on top
of that, I've learned huge amounts about various
aspects of Ultralighting and, really, radio in general and had a BARREL of fun.
I've got to get another cup of coffee and start
on over 25 more DXing award certificates that
have been checked and verified by Rob Ross this
week.... but it sure is nice to stop for a few
minutes to think about the bigger picture. It is
very nice to have you all around. It makes my
life much richer. Yours, too, I hope!
John Bryant
Moderator
At 03:18 AM 1/22/2010 -0500, you wrote:
In a message dated 1/21/2010 11:56:01 P.M.
Pacific Standard Time, roy.dyball@... writes:
Also remember if you are dynamically tuning your
loopstick by unwinding turns or repositioning
it, that with every change you make to the
loopstick you must steep off the frequency you
are on and then steep back again, this gives the
Si4734 a chance to update its varactor and
choose a new corresponding value for the change you just made.
Cheers Roy.
Hello Roy,
Thanks for mentioning this. In the dynamic
tuning of the PL-380 "stealth models" (a 40/44
Litz wire coil of about 433 uh inductance on the
stock ferrite bar), I found this was very true.
In both of my two models, the original coil of
about 500 uh had an Si4734 varactor lock-up
issue on the high AM band frequencies, and coil
turns needed to be subtracted one by one until
the radio had a sudden boost of sensitivity on
1700 kHz. (There was no option to use a Slider
coil for loopstick tuning purposes, since the
flat stock ferrite bar was geometrically unsuitable as a Slider coil base).
After the sudden rush of increased 1700 kHz
sensitivity on the PL-380 when the inductance
was lowered to 433 uh, it was necessary to move
off of the frequency and then back to 1700 kHz,
to judge the final RSSI increase after the
modification. The dynamic signal
"turn-subtracting" strategy (to lower the coil
inductance to a level acceptable to the
varactor) was a weird idea that ended up giving great results.
73, Gary
|
