UHF/SHF

23cm Wide/Narrowband

For 23cm I started out with ATV Amateur Television with a 24 element JVL design Loop-yagi antenna made from copper brake pipe and aluminium U section about 2m long. This worked very well for Receiving ATV and has a reasonable amount of gain, but I managed to get hold of 2x28 element G3JVL yagi's off-the internet on G3CWI's site including a 1W ATV transmitter. This was bought in dec 2003, the gear finally came in may 2004! ! ! The guy who I bought it off had some family problems and the gear was not one of his main priorities! All was ok in the end but I was about sick of waiting! ! .
Anyway, these antenna's were phased together and improved the 23cm setup dramatically and with the transmitter I could join in with the other local stations finally.

Next on 23cm I bought a transverter from gm4wll, a kit made by DEM in the USA.
Now I can hear the GB3MLE beacon over 80km away at S7 all the time, with the old homebrew antenna it is only about S1 ! ! Since then I have added a preamp on 23cm and switching relays at the top of the mast for tx/rx and replaced all the coax with mostly Andrews heliax LDF4-50 which reduced losses A LOT, this is the way to go with microwaves :)

PD0RKI 23cm Amplifier installed for both EME and tropo setup ~110W for 8W input (early design)

@2012

Currently on 23cm i'm using the TS-2000x in the shack as the driver radio for the remote amplifiers at the mast. This is currently the 100W amp from Bert seen below but being replaced with a much bigger one... the idea was to get a better signal out on EME which is will certainly do but for now will live on the main tropo setup.

I also replaced the 2x28el G3JVL LoopYagi's with two 44el SHF design ones (May 2012) for a bit more gain too, the LoopYagi's are now solely used for portable operation.

The latest amplifier is much more capable, it is based on the boards that WERE availble from Jim W6PQL and capable of delivering about 600W!

I bought the boards and high power splitter/combiner in late 2009 with intentions of getting it up and running rather quickly but it did not progress until late 2011, just about complete now in July 2012.

Currently i have tested it briefly to around 500W with an external coupler but the meter is not accurate enough to say precicely, DC input current is ~37A @27v on max output so sems to tally up. I have not used expensive ATC capacitors for the output of each amp stage (only Farnell's uWave ones rated at 200v) nor the trimmers so this is probably whay i have a little less than what maybe possible...

I did not like the idea of snowflaking and tweaking the amp in close proximity at 500W!! so quite happy with the output power as-is, no need for any adjustment! I just put the lid on and installed it near the tropo antennas & dish.

The previous DG0VE 60W amplifier is used to drive the big amp as i only have max 2W available at the end of the coax at the mast where the amplifier will be located.

The controller/Sequencer is 'The ultimate Amplifier Control Board' by W6PQL.

The home made directional coupler made from 0.25" copper coax works fairly well, i had to enclose the coupled port ends in the tin box to stop RF pickup from the output combiner due to it's proximity.

The output N socket is fairly good quality but had to be 'bodged' to accept the different size coax.. it has held up OK so far!

Here's the insides... top

and bottom...

There is still some finishing off work to do but Initial tests this Tuesday Activity night were promising with... 'You're loud today...' signal reports ;-)

Hopefully next time i get the big dish in operation the echoes from the moon will be much improved!

(Handy diagram: Yaesu FT-736R 23cm module schematic (5Mb) - I hope you never need it !)

Recordings from the Tropo opening in Late January/Early February 2006 on 23cm SSB.

DJ7JG

DJ6JJ

DK6AS

DM2AFN

F1ANH

DX in 2007

LA3EQ

OZ3ZW

DX in February 2008 3 new squares worked :-)

OZ5BZ

SM7ECM

PA2M

DX worked on 1296MHz since 2005 from IO94IL

Updated August 2008

Mast Control Setup

2006: Currently updating the antenna setup with all amplifiers and antenna switching done at the bottom of the mast.

Shack Control Box : PTT control and monitoring of the remote power sensors etc..

23cm Remote Unit : New 23cm Amplifier from Bert, PE1RKI installed giving >100W (can't yet measure!)

Try this simple Sequencer by G3SEK, works a treat. Only difference is that i used a 2200uF for a longer delay.

Mast Remote Cabinet : Currently seeking a weather proof cabinet to house the 2m/70cm/23cm amps, pre-amps, relays, batteries etc..

Photos:

23cm GB3MLE beacon aircraft scatter

2M Dish