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 #1376
Joined: Wed Mar 05 2008, 08:31AM
Location:
Posts: 49
Hello,
I would like to start preforming some experiments in the Super High Frequency Spectrum using a microwave transmitter, but am unfamilier with the equipment and procedures at this frequency range. Some help getting started would be appreciated.
In paticular I am interested in this piece of equipment, but could not find any information on the internet about it (Data Sheets/manuels).
Eyal Gal RF Transmitter Microwave ED-0295-0 7.1-7.9GHz
Perhaps someone here knows what this transmitter would have been used for.
In addition, does anyone here have information on the pulsing of microwaves?
Registered Member #30
Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706
I remember the Unilab microwave apparatus from my high school physics lab.
It consisted of two boxes with horn antennas sticking out of them. One box had a small low-powered klystron inside and the other had a detector diode and meter.
Who knows, maybe you can find something similar in a surplus store?
Registered Member #543
Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992
Here is an extract from the UK Table of Frequency Allocations for 7 - 8 GHz. Usage in other jurisdictions is likely to be very similar and shows the kinds of applications your device was intended for. As you can see, there is no allocation for licensed amateurs in this frequency segment.
A transceiver based around a scavenged 10 GHz Gunn diode module is probably the easiest way onto the microwave amateur bands.
Have a look at A simple wideband FM 10GHz transceiver with 30MHz I.F. by G3PHO to get some ideas.
PS: If you haven't got a 30MHz receiver, you can easily construct a single-transistor super-regenerative detector tuned to 30 MHz as your IF amp and detector. It won't be as good as using a communications receiver, but will work fairly well in wide-band single frequency use on uncrowded bands, with sensitivities down to a few μV possible with careful construction.
Registered Member #1376
Joined: Wed Mar 05 2008, 08:31AM
Location:
Posts: 49
Thank you very much for your responses, In particular the link Proud Mary gave. Please excuse my extreme lack of knowledge on this subject but the issue I can see myself having with the 10 GHz gunn diode is that I require an output connection to test various coil configurations as antennae. The Solfan Doppler Module has only a wave guide output. I understand that working with high frequencys like this is very difficult because the wavelength is about 30mm and care needs to be put into the design.
This has given me a good starting point in any case.
Registered Member #543
Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992
Hi Plasma,
You may also find The Radio Amateur's Microwave Communications Handbook helpful, which you can download free here:
This 1985 book is a bit short on circuit diagrams and construction at the basic component level, but still contains much that is worth knowing.
The 2.3GHz 13cm amateur band is a much more accessible place to get started, in terms of money, theory, workshop equipment, and constructional skill.
As for waveguides, don't forget that circular waveguides (copper pipe, tin cans! ) of diameter appropriate to the frequency work far better than any coaxial cable, though their propagation mode is a bit different to the more common rectangular waveguide type. Google tin can waveguide and/or coffee can waveguide to see how it's done.
Registered Member #30
Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706
The idea of a "coil" as a microwave antenna doesn't really make sense.
You can make a "Tesla coil" by attaching a 2.5cm length of wire to a metal disc and placing it in your microwave oven. With only 2.5cm of wire in the "secondary", what is the point of coiling it up?
Registered Member #1376
Joined: Wed Mar 05 2008, 08:31AM
Location:
Posts: 49
Hello Steve Conner.
As I mentioned before, I have very little knowledge in microwave frequencys therefore it is purely for experimental purposes. I am interested in what would happen if you connected a microwave signal of such physically short wavelength to an inductor of similar dimensions. Perhaps in a similar arraignment to the picture that is attached.
I have found a Microwave VCO here: There appears to be three pins, VCC, Vt and RF. Further to this, I came across a web page detailing the construction of a 2.3GHz transmitter. Would anyone know about amplification of signals at this frequency? The Pulsing of Microwaves is also of interest.
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.