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Re: [IRCA] Antenna Projects (Crate Loop) MORE QUESTIONS
Thanks. I have seen the multi-gang variable capacitors and was trying
to see how I could apply them for this project. A switch, Dave, duh.
That must be what the switch was for on the amp/tuner of my old
Sanserino loop (double duh). I forget the ranges that it divided the AM
band into but that makes perfect sense! Maybe I could cannibalize
that....
I actually have an old hardly-working, Heathkit general coverage SW
receiver that probably has a multi gang vc inside (I bought it years ago
at a garage sale for $5 or $10).
KEVIN: There is another "option" for your "Crate Loop" plans, a switched
multi-gang vc!
What equipment is needed to check the capacitance of a vc?
Thanks again, Chris.
73
Dave in Indy
-----Original Message-----
From: Chris Knight [mailto:chris@xxxxxxxxxxxxxxx]
Sent: Friday, January 09, 2009 12:38 AM
To: HASCALL, DAVID CIV DFAS; irca@xxxxxxxxxxxxxxxx
Subject: RE: Antenna Projects (Crate Loop) MORE QUESTIONS
Dave,
EBay has been a pretty good source for wire. I usually buy spools of
1000'
or less and dedicate some of them to antenna projects and others for
Beverage Antennas, etc.
An observation on "fine tuning": You'll notice the 0-365pF single gang
capacitor is "touchier" when less capacitance is needed at the higher
BCB
frequencies. As you tune the loop for stations under 700kHz it becomes
easier to tune and a lot less touchy. So, what I've done in the past is
use
a multi-gang capacitor such as the C-V365-X3 available at Antique
Electronic
Supply http://www.tubesandmore.com/ for $26.96. You can tie 2 of the
gangs
together in parallel and switch them in using a toggle-type switch or
you
can switch each gang in individually as needed using 2 switches. This
gives
each gang the full tuning "range" of the capacitor. Hence, you get
better
fine tuning.
73.
Chris
-----Original Message-----
From: HASCALL, DAVID CIV DFAS [mailto:DAVID.HASCALL@xxxxxxxx]
Sent: Thursday, January 08, 2009 8:54 AM
To: irca@xxxxxxxxxxxxxxxx
Cc: Chris Knight; satya@xxxxxxxxxxxx
Subject: RE: Antenna Projects (Crate Loop) MORE QUESTIONS
Thanks Chris. I'm more reassured now, as it sounds like an amp is not a
major necessity.
Kevin, Chris and Everyone:
1. Where would be a good source of 16 or 18 ga single conductor,
stranded wire? Since I'm not very handy I don't hang out at Home Depot,
Menards or Lowes :) but I'm sure that type of store would be a best bet.
How much would 120' or so run?
2. Where is a good place to find a "fine tuning" variable cap, if
needed? I see some trimmer capacitors at All Electronics, 2 for a buck
but they of course, do not have a long enough shaft. Here is another
one: it's 0-160 / 0-60pf (combo, I guess) for $2.47 but it's tuning
shaft is in the same boat.
http://www.scitoyscatalog.com/Merchant2/merchant.mvc?Screen=PROD&Product
_Code=VARICAP&Category_Code . Chris provided a link for ordering a 365pf
variable cap. Unfortunately I disposed of two inoperable AM radios over
the Summer and those would have surely led to a good main variable cap
(and probably nice sized ferrite loopsticks). D'oh!
3. Again I'm not tech oriented so how do you determine the value of a
variable cap? I don't think I have a VOM meter, if that can even be
used to check but my son-in-law has a digital meter.
I found what looked to be a good crate at Goodwill (my favorite store
for finding neat DX stuff) but it was more like a milk crate - too
heavy. I'll try to pick one up this weekend.
Thanks for helping a low (no?) tech guy out. 73,
Dave in Indy
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