If you need assistance, please send an email to forum at 4hv dot org. To ensure your email is not marked as spam, please include the phrase "4hv help" in the subject line. You can also find assistance via IRC, at irc.shadowworld.net, room #hvcomm.
Support 4hv.org!
Donate:
4hv.org is hosted on a dedicated server. Unfortunately, this server costs and we rely on the help of site members to keep 4hv.org running. Please consider donating. We will place your name on the thanks list and you'll be helping to keep 4hv.org alive and free for everyone. Members whose names appear in red bold have donated recently. Green bold denotes those who have recently donated to keep the server carbon neutral.
Special Thanks To:
Aaron Holmes
Aaron Wheeler
Adam Horden
Alan Scrimgeour
Andre
Andrew Haynes
Anonymous000
asabase
Austin Weil
barney
Barry
Bert Hickman
Bill Kukowski
Blitzorn
Brandon Paradelas
Bruce Bowling
BubeeMike
Byong Park
Cesiumsponge
Chris F.
Chris Hooper
Corey Worthington
Derek Woodroffe
Dalus
Dan Strother
Daniel Davis
Daniel Uhrenholt
datasheetarchive
Dave Billington
Dave Marshall
David F.
Dennis Rogers
drelectrix
Dr. John Gudenas
Dr. Spark
E.TexasTesla
eastvoltresearch
Eirik Taylor
Erik Dyakov
Erlend^SE
Finn Hammer
Firebug24k
GalliumMan
Gary Peterson
George Slade
GhostNull
Gordon Mcknight
Graham Armitage
Grant
GreySoul
Henry H
IamSmooth
In memory of Leo Powning
Jacob Cash
James Howells
James Pawson
Jeff Greenfield
Jeff Thomas
Jesse Frost
Jim Mitchell
jlr134
Joe Mastroianni
John Forcina
John Oberg
John Willcutt
Jon Newcomb
klugesmith
Leslie Wright
Lutz Hoffman
Mads Barnkob
Martin King
Mats Karlsson
Matt Gibson
Matthew Guidry
mbd
Michael D'Angelo
Mikkel
mileswaldron
mister_rf
Neil Foster
Nick de Smith
Nick Soroka
nicklenorp
Nik
Norman Stanley
Patrick Coleman
Paul Brodie
Paul Jordan
Paul Montgomery
Ped
Peter Krogen
Peter Terren
PhilGood
Richard Feldman
Robert Bush
Royce Bailey
Scott Fusare
Scott Newman
smiffy
Stella
Steven Busic
Steve Conner
Steve Jones
Steve Ward
Sulaiman
Thomas Coyle
Thomas A. Wallace
Thomas W
Timo
Torch
Ulf Jonsson
vasil
Vaxian
vladi mazzilli
wastehl
Weston
William Kim
William N.
William Stehl
Wesley Venis
The aforementioned have contributed financially to the continuing triumph of 4hv.org. They are deserving of my most heartfelt thanks.
Registered Member #543
Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992
Dr. Slack wrote ...
Proud Mary wrote ...
My dismay at finding I could do nothing at all with the jumping flea SMD chips has been reversed by a compromise that took me ages to fall upon due to my unfamiliarity with the technology. I can nothing with 100 pF 50V chip capacitors, but found that 100 pF 1000V was just about big enough for me to use my standard soldering skills. The same with chip resistors: I can work with the 2W ones just fine! This still means that I shall not be able to reach the higher microwave frequencies, but is still a big advance over my previous thru-hole axials in the direction of miniaturisation.
Are you sure that the limitation is that you can *do* nothing? I used to think I didn't have the control skills to solder small stuff until I used a decent microscope. Then I realised it was simply because I could *see* nothing. Once I had sufficient gain in my optical feedback path, I found I could achieve good connections with 0402 parts routinely, and 0201 with a bit of care. Even stacking an extra pair of +4 reading glasses over your standard ones can bring about huge improvements.
I'm sure you are right and that there is an element of that in it. And yes, good magnification is essential, but I still have to deal with unsteady old hands that first held a soldering iron 50 years ago. Starting with the larger components, and then working my way down in scale when I have acquired a bit of skill seems a sensible way to go. :)
Registered Member #162
Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140
Detecting Pulsars .... from the link posted it seems that ONE or TWO are actually detectable by amateurs, not a very exciting prospect.
My two as yet unfulfilled radio aspirations are . chatting with ISS astronauts/cosmonauts . earth-moon-earth communications. (moon bounce)
I have not worked with 0201 smd, 0804 is as small as I want to go. I prefer 0.1" matrix and through-hole components but like me they are now obsolescent :(
Registered Member #543
Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992
Sulaiman wrote ...
Detecting Pulsars .... from the link posted it seems that ONE or TWO are actually detectable by amateurs, not a very exciting prospect.
My two as yet unfulfilled radio aspirations are . chatting with ISS astronauts/cosmonauts . earth-moon-earth communications. (moon bounce)
I have not worked with 0201 smd, 0804 is as small as I want to go. I prefer 0.1" matrix and through-hole components but like me they are now obsolescent :(
I've seen people who've broken the bank making costly subterranean inductors of enormous size to detect the Schumann Resonances, but find themselves with nowhere to go once they have the Resonances resonating on the screen in front of them. So I think you are right about the pulsars pulsing away if you can detect them to which I'll add detecting the 21cm Hydrogen Line which is a goal of some rtl.sdr enthusiasts. Years of observation and something might change but otherwise it is hard to go further.
What I do find exciting is ultra-narrowband (1 Hz!) communication, where even a tinkerer of modest abilities such as myself can experiment at modest cost and perhaps surprise even myself with the distances that can be covered with just a few milliwatts. :) This - and the 8.97 kHz 'Dreamer's Band' - is the direction I hope to take my rtl.sdr experiments. :)
Registered Member #162
Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140
In the late '70's RS used to sell a doppler radar module, I made a simple speed meter using one, passing the mixer output to an audio amplifier allows you to hear the tones, quite interresting. Certainly worth a brief 'play'.
Registered Member #543
Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992
Thank you so much for your very kind offer, Andre, but I have more stuff than I could ever hope to tinker with in a single lifetime and am very pushed for space to store what I already have.
This site is powered by e107, which is released under the GNU GPL License. All work on this site, except where otherwise noted, is licensed under a Creative Commons Attribution-ShareAlike 2.5 License. By submitting any information to this site, you agree that anything submitted will be so licensed. Please read our Disclaimer and Policies page for information on your rights and responsibilities regarding this site.
Microwave mixer diode substitutes
