My activities on 10GHz
(non - ATV)
* 10 GHz Logbook: a collection of photo's and info for various 10GHz outings
* My Transverter Systems
* IC 290H Mod for feeding 8VDC up the coax
My Gunn Osc Systems
As back in ZL, I have again started with WBFM mode using Gunnplexers and I have also found more amateurs in VK
interested in experimenting in the SHF bands which has spurred me into more serious action.
Below are examples of Gunn Oscillators that I have. In the left pic is a Gunnplexer on the left and on the right a dual
side-by-side cavity oscillator/mixer unit commonly used in door opener systems.
The right pic shows MA/COM (Microwave Associates - Now Tyco) Gunnplexers for 24 and 10 GHz, both of which are
used in some of the gear I have for those bands.
The 3 pics below are of my two WBFM 10 gig xceivers. The top pic shows the inside of one unit that has just a modulator,
tone generator and power supply board in it. At the moment an external 30 MHz IF receiver is used, with room in the
case for the future addition of a RX board.
The lower 2 pics show the front panel and inside views of my full TX/RX WBFM unit. This transceiver uses a MA/COM
Gunnplexer (as shown in above pic) mounted externally along with a 30MHz preamp (~19dB gain at 1.1dB NF) and a horn
antenna (~ 12dB gain). Here you can find the circuits and block diags for the upper basic transmitter and the lower
full tranceiver. Both these units run happily off 12V 7.2AH sealed lead acid batteries for portable use.
With the advent of affordable priced satellite LNB's (AU$30 - July2008) we now have an easy transceiver system for WBFM.
The LNB has a gain of >60dB and a NF of 0.6dB and a LO freq of 10.7GHz. These units are ideal for 10GHz WBFM ops.
10.7GHz LO - 10.350GHz of Gunn TX = 350MHz IF, easily received with a scanner receiver.
Click on images below for full size pics
My Transverter Systems
My main 10GHz transverter is one by Down East Microwave (DEMI) that I purchased as a kitset during the visit to the Dayton
Hamfest in 2006. This unit operates very well having ~ +13dBm (20mW) output and a good lownoise ~ 3dB NF GaAsFET receiver.
Left - Pipecap Filter side of Main brd and Control brd; Centre - LO board; Right - Main brd, component side during Tune-up
My first onair contact was on the 21 June 2008 (also being my first 10gig SSB QSO) Go here for details
Below are pics of the Narrow Band xverter built by Lyle, VK2ALU and purchased by me in 2004. This xverter is based
on the G3JVL system as described in the RSGB Microwave Handbook. The left pic shows the insides of the unit and
the right pic shows the xverter mounted on the back of a cassigrain fed .6 metre (~2ft) dish, which in its past life was a
spotlight reflector. A short length of WG16 waveguide terminating in a small horn at the focus of the sub-reflector.
Lyle, VLK2ALU, had played with variations on the original design and one of the main experiments was with a higher power
transmitter as the main unit only had a 1mW output. He used that 1mW signal to injection-lock a 120mW Gunn oscillator
with reasonable success. Look here for block diag. of the system.
The transceiver is designed to operate on the standard 10.368 GHz using SSB. I have not used this transceiver yet, primarily
because there isn't anyone else to talk to in the Sydney region on 10 gig SSB. It will be a future project. In the mean time,
I and others will continue to refine our WBFM systems and gain more experience of operating on these frequencies.
Click on images below for full size pics
IC 290H Mod for feeding 8VDC up the coax
Having to modify my Icom IC290H allmode transceiver to supply +V on the antenna socket during transmit came about when
my trusty old Yaesu FT290R started playing up and became unusable.
In late 2008, I also modded my Yaesu FT897D to give +VDC on the VHF/UHF antenna socket so that I could use that radio
either as a backup in the field, if the 290H failed, or just as a transverter test rig on the workshop bench. With the 897D, the
TX voltage is only 5V and I deemed this too low for reliably switching relays/transistors etc after the inevidible bit of voltage
drop in the coax feed. So I used the +5V on TX to operate a relay to switch the 13.8 V tranceiver supply via a 7810 +10V
3 terminal regulator. That 10V then went via a current limiting resistor and RFC's to the antenna socket. It Works Well !!
I may put up a cct and photo of that mod at some stage when I have time.
Usual Disclaimer .... Do All Mods At Your Own Risk ... I Take No Responsibility :)
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Page created 08 July 2008
Page updated 21 Feb. 2009