Date: Sun, 23 Feb 1997 10:29:27 -0500 (EST)
From: Joe Everhart <n2cx@voicenet.com>
To: qrp-l@lehigh.edu
Subject: [12841] Info needed re drills
Message-ID: <199702231529.KAA25401@mail3.voicenet.com>
Mime-Version: 1.0
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Gang,
Yes this really is realted to qrp'ing in the homebrew sense.
Can anyone tell me the decimal sizes for twist drills in the
sizes of No. 50 to No. 60? I'd like the sizes fo each drill
in that range.
If I were at work, I'd just ask an ME, but here at home....
Thanks and...
72/73,
Joe E., N2CX
Joe,
I found the information you need in two places. First in the Radio Shack
Electronics Data Handbook Cat. No. 62-1085 Pages 151-155. Also in Appendix
A1-DRILL of the Paul Harden, NA5N "The Electronic Data Book for Homebrewers
and QRPers" . Shame on you for not having at least one of them. :^).
Feeling sorry for you, Here is the Information you requested.
#50 = .070 #51 = .067 #52 = .0635 (.064) #53 = .0595 (.060) #54 = .055
#55 = .052 #56 = .0465 (.047) #57 = .043 #58 = .042 #59 =.041 #60 = .040
The first figure is from Radio Shack Book, Figure in ( ) is NA5N book.
From: James Parsons <k5rov1@worldnet.att.net>
To: qrp-l@lehigh.edu
Subject: [12846] Toroid info needed...
Message-ID: <1.5.4.32.19970223153719.0066f064@204.127.3.1>
Mime-Version: 1.0
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I am planning on modifying a home brew QRP rig from 15 meters to 30 meters.
I need to know the MIX for a T50-7 (white) toroid. Neither my Amidon manual
(old) nor Hamcalc program mentions the -7 series. To calculate the turns for
the VFO frequency I plan to use, I need the MIX info. Can anyone help?
Thanks and 73...
Jim, K5ROV
Hi Jim,
Your information was located in the Paul Harden, NA5N QRP DATA BOOK.
Data Sheet Section, Inductors, Toroidal Sheet IND-2T.
The Type 7 Core Material has a u=9, Color Code = White, Freq. Range 3-35 MHZ,
A L Range (uh/100 turns) of 29-52, Temp. Coeifficient= 35 ppm, Core Type is
Powdered Iron. This Mix is recommended for General HF Applications.
Ie., It is Good for use in the VFO Circuit.
O.K. Kids, one last reminder... It's in the Book!
**************************
O.K., one last item,
I am still reading thru my past weeks Digests, so this one may have
already been answered or help provided.
I forget the details right now, but the gist of what I recall reading made
me wonder if part of the problem was not in the methods used in testing the
XCVR. I think it was a 38 Special. First, no mention was made to the fact off
whether or not a Dummy Load was used. NOT GOOD IDEA to forget that little
item, even if you are testing a QRPp Rig. No sense in making it EASY for the
"Smoke Genie" to get out. :^) The part that really concerned me was part
about connecting the 914 diode cathode to the VOM Positive probe (in Series?)
and making RF? measurements. I would recommend taking a peek at an ARRL
Handbook, or one of the many QRP Handbooks and find out how to make a simple
RF Probe. I actually found just what you need in the July 1991 QRP Quarterly.
I didn't think that it was that long ago, but I just had to find it
because it was one of Joe's Tips (N2CX) That kind of Stick with you.
Basically it is a .01 uf Capacitor in series with a 3.9 Meg. Ohm resistor
which is in turn in series with the + Meter lead of your VOM/VTVM.
Oh Yes, we don't want to forget Mr. Diode (a 1N34 Type) (Germanium, not
Silicon).
This is placed with it's Cathode connected between the junction of the .01
Cap and the 3.9M resistor, The Anode of the Diode is connected to circuit
Ground, as is the negative meter probe.
The other end of the .01 cap. is your RF probe. If greater
accuracy is desired, you will need to make the Resistor a 4.14 Meg.Ohm unit.
It is accurate within about 2% with the 3.9M resistor. This is assuming you are
using a 10 Meg. Ohm input VOM. What I liked about Joes Idea, was that the
3 components (.01 cap,3.9M Res. and 1N34) are so cheap, you can just solder
them in the circuit and leave them there for future testing. There you have
it in a nutshell. Try it and see if it dosen't change the picture a bit.
GL es QRP DX TU
Danny K3TKS@abs.net
Maryland Milliwatt QRP Reference Library, (301)572-6789
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