 |
ARRL Products:
Interference/DF(More)
The RSGB Guide to EMC -- Tackle RF interference problems and understand the underlying causes.
AC Power Interference Handbook -- New insights into the causes, effects, locating and correction of power-line and electrical interference. 3rd Edition.
Transmitter Hunting -- Radio Direction Finding Simplified
The ARRL RFI Book -- Now Shipping!
-- Second Edition. Practical Cures for Radio Frequency Interference.
Amateur Radio Astronomy -- Explore the contributions of radio amateurs, and how to make and set up equipment to study the signals coming from space.
|
|
|
September 2006 QST Feedback
In my article "When Will the Bands Improve?" [Jul 2006, p
46] the definition of the length of a sunspot cycle should read: "The average
length of a sunspot cycle, from solar minimum with a minimum number of sunspots
(low electron density) to solar maximum with a maximum number of sunspots (high
electron density) and then back down to the next solar minimum, is
approximately 11 years." -- Carl Luetzelschwab, K9LA
In "Homebrew Solid-state 600 W HF Amplifier [Jun 2006, pp
39-43] R3 and R4 in Figure 1 should be omitted. The resulting bleeder current
is 1.1 A; the value in the text is in error for either configuration.
Update: In the "A CAT5 Cable and Connector Tester" [Jul
2006, pp 52-53] the CAT5 crimping tool listed in the article, #115-1321 is no
longer available. The correct item number is #115-2158.
In my article, "A Neat Dual Band Antenna" [Aug 2006, pp
50-51] the "upper aluminum tube" length in Figure 4 should be 22 1/8 inches as
shown correctly in Figures 2 and 3. -- Geoff Haines, N1GY
Clarification: The impressive AO-40 satellite dish
on the cover of the August 2006 issue was built and installed by Jerry Brown,
MØMOE/K5OE, at his home in Houston. (He now lives in London, UK.) "The dish," he writes, "is a surplus 4 foot UHF TV antenna (from
the '60s) with a homebrew L/S dual-band feed. The two cross-Yagis (V/UHF) are
PVC pipe and copper wire using a folded-dipole feed from a satellite-specific
design I presented at the AMSAT-UK Colloquium in 2000. The two boxes contain
coaxial relays for switching antenna polarizations on the V/UHF antennas."
Clarification: In the sidebar, "Power Measurement and the Alpha
Power 4510" in the July 2006 issue [Product Review, p 63], power is defined
more precisely as the quantity of work performed per unit of time. -- tnx
Doug Smith, KF6DX, and Jon Tandy, K9KNC
Page last modified: 12:52 PM, 01 Aug 2006 ET
Page author: qst@arrl.org
Copyright © 2006, American Radio Relay League, Inc. All Rights Reserved.
