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 #177
Joined: Wed Feb 15 2006, 02:16PM
Location: Munich, Germany
Posts: 214
Is their a feasible way to build a 800Mhz band receiver? Our professors use this band for their micros, and sometimes some jerks just wont shut up about last sundays soccer game and stuff like that. So it would be fun to build a receiver, that could just tune in in such moments.
Is their a relaible way to do this, or is this out of reach?
Registered Member #162
Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3141
I'm not an amateur radio guy - some here are and may help, I doubt that design would be much use - you may hear local transmission (I'm guessing wildly - 10m?) but there would be so much other stuff picked up that I doubt it would be useful.
Exactly the same circuit with a 1/4 wavelength aerial (and possibly a tuned circuit) might work though I've never operated at anything like 800 MHz so I'm guessing.
Registered Member #89
Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145
The thing you will mostly hear 50Hz hum with this receiver.
Basically you can build 'crappy' AM (you didn't even note what modulation you want) receiver for a wide range of frequencies by just hooking an antenna, LC, and fast, low-drop diode to an audio amplifier and you can listen to it.
When you want something more it gets a bit more complicated at 800MHz (you need some pretty fast transistors if you want HF amp, regenerative receiver etc.)
Just use some kind of amplifier, for me TDA810 worked well, make it work and then just hook it to what is described above.
You need a good antenna and diode (schottky made for the purpose or germanium) and you will hear most AM stations just by messing the LC.
I did this long ago but I didn't bother getting antenna on the roof so results weren't too good.
Registered Member #16
Joined: Thu Feb 02 2006, 02:22PM
Location: New Wilmington, PA
Posts: 554
I'm not familiar with what a 'micro' is. I'm assuming its a cellular phone?
If thats the case, by US law no commercial receiver sold here is allowed to be capable of receiving the 800Mhz cellular telephone band. I dont know about Germany, but in the US the 800Mhz band is virtually obsolete, and I dont know of any new phones that are only capable of the lower band. Almost all of them are 1.2 Ghz now, and are trunked.
A receiver for this high of a frequency would not be a small undertaking. FM receiver design is a pain in the ass to begin with, much less at a frequency where a poorly designed corner on a PCB can ruin the circuit.
Registered Member #65
Joined: Thu Feb 09 2006, 06:43AM
Location:
Posts: 1155
Dave is right about the retail units, Even the old GSM bands etc. are locked out on the import units... FCC rules...
If you are a service tech you will know how to get around this limit. However, what would be the point if you already legally own one that has no limits on this band.
Transceiver units that do not show a FCC id number are most likely not legal to run in the US.
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.
800Mhz receiver
