Home |
Search |
Today's Posts |
#2
![]() |
|||
|
|||
![]()
On Tue, 8 Apr 2014, Geoffrey S. Mendelson wrote:
I have a copy of the book "Practical Wire Antennas" by Heyes (the first edition). In it is a schematic for a low noise broadband preamplifier for loops. This version uses the BSX20 transistor which at the time the book was written was far more available in the UK than the 2N5179 used by the original Hayward design. The book mentions that it was first published in the ARRL Antenna Handbook, I can not find it in my copy. THose things, like the Handbook, change glacially, but unless you had the right edition, it wouldn't mean a thing. A "broadband 2N5179" preamp is kind of vague. It might have come from "SOlid State Design for the Radio Amateur", lots of small schematics in there, and not all projects. But I can also see some sort of loop in QST circa 1976, that had a preamp that also might have fit. Though I thought that article was by someone on the ARRL staff, like Doug DeMaw. But, it might be attributed to Wes Hayward, since they seemed in constant correspondence at the time. I may look in the book later, if I remember and get around to it, see what might be there. Michael These days it is much cheaper and easier to order 2N5179 transistors from China on eBay (and probably cheaper to order 10 and pick the best) than it is for me to order a BSX20. However without the original schematic or construction article, I am taking it on faith that it will work with no circuit changes, something I doubt. A copy of the schematic and accompanying text would be appreciated. References to where it appeared or links to pages describing it would be even better. The original circuit I was looking at contained 1 transistor, 4 diodes, 6 1/4 watt resistors and 4 disk capacitors. The coil could be wound from hookup wire on a hunk of ferrite rod, which I have many of. It's fairly "bulletproof", so high voltages from static, lightening or nearby transmitters (all three here) won't burn it out like an MMIC. It's a simple design so that I can build it myself. :-) TIA, Geoff. -- Geoffrey S. Mendelson, N3OWJ/4X1GM/KBUH7245/KBUW5379 |
Thread Tools | Search this Thread |
Display Modes | |
|
|
![]() |
||||
Thread | Forum | |||
Hayward design broadband low noise preamp for loops | Antenna | |||
Questions on broadband antenna design (e.g. T2FD) | Antenna | |||
Full wave loops - alternate design? | Shortwave | |||
Noise and Loops Question | Antenna | |||
Advice Needed for Super J-Pole Design: Inductive Loops Overheating | Antenna |