Hipersil, what’s behind? by Will Matney I was asked about a transformer using nothing but a Hipersil transformer. I offered an EI type, M6 material transformer of the same specs, but it wouldn’t do. Well folks, this gave way to me writing this for all on what exactly is […]
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The 4 rule The reactance of the windings should be at least four times the impedance the winding is designed to look into. where Zi … input impedance Zw … winding impedance thus where Lw … winding inductance Zi … input impedance f … design frequency To find the number […]
This description is taken from the Pete's W2PM posting into Topband reflector.
This antenna is very simple - it's a mini diamond Flag - with a 660 ohm terminating resistor and a 16:1 transformer. It is the exact size of the so-called magnetic loops, - 5 ft per side, 20 ft total wire, and about 7.1 ft wingspan. It has classic Flag cardiodal pattern and, of course, pretty low output (-50 dB from what I recall). F/B is about 30 dB. I use it with a single preamp with good results. This antenna is quite easily rotatable as you can see (altho the standard 15 X 30 ft Flags have been made rotatable too as most of you know).
This has several advantages over the "mag" loop (for those on small lots) - it's broadband 1.8 MHz past 30mhz; cardioid pattern with very nice null to rear, decent low angle take off (abt 32 deg) AND is simple - make it in minutes. I used 2 - 330 ohm resistors a binocular 16:1 transformer. I "potted" the resistors and xfrmr in epoxy.
I've since cleaned mine up - routing the RG-174 coax from the transformer to the center of the crosses, then connect it to a RG-58 run vertically down the mast.Thanx loads to Earl K6SE for the design.73 Pete, W2PM
by Louis Varney, CEng, MIEE, AIL, G5RV* * (taken from RADIO COMMUNICATIONS, JULY 1984) THE G5RV ANTENNA, with its special feeder arrangement, is a multiband centre-fed antenna capable of very efficient operation on all hf bands from 3.5 to 28 MHz, specifically designed with dimensions which allow it to be […]
Geoff Cottrell, G3XGC, describes his coaxial receiving loop in the March issue of Practical Wireless [1] (download here). This article is widely available over the internet, which is a good point. The less pleasing fact is that this article contains a 'bug' - the primary of the transformer T1 should not be connected to C1 but to the other end of the loop (ie. to the ground).
Here is a printer friendly copy of the Edmund A. Laport’s textbook Radio Antenna Engineering credits and thanks go to Dave Platt, AE6EO The Book Radio Antenna Engineering was published in 1952, and presents an excellent overview of the state of commercial antenna system engineering as practiced in the first […]
LAST UPDATE: 29-MAR-2023 This free downloadable QSL Manager Database provides simple QSL info in CSV text format containing the DX call, QSL manager’s call and the date of first publishing. No addresses, no other info. This file is intended for use with most recent versions of CQRLOG for Linux but […]
P1D-1V P2D-2V V1D-2V1 P1D-3V P2D-3V V1D-2V2 P1V-1 P4D-1V V1D-3V1 P2D-1AV P4G-2V V1D-3V2 P2D-1V P5G-2V V1D-4V
Tubes Sockets Documents and White Papers Most wanted: FU-728F (another datasheet here) Tubes 2C39A (Eimac) 4PR1000A GS-31B QY3-1000A TB1-60 2C39A (Philips) 4PR400A GS-35B QY3-125 TB2-500 2C39B 4X150A GS-3A QY3-65 TB2.5-300 2C39WA 4X150A GS-9B QY4-400 TB2.5-300 (another datasheet) 3-1000Z 4X150A GS14 QY4-500A TB2.5-400 3-1000Z 4X250B GS15B QY5-3000A TB2.5-400 (another datasheet) 3-400Z […]