Replacing the IO92GQ internet-only repeater
DTX-1 at 1.3Ghz mixing with ADF4351 at 2.108GHz, filters and mixer...
Amazed how well 3.408Ghz working across workshop, very low signal from horn across to Titanium C1W-PLL Lnb, still playing with levels and filters...
RPi animated test card very useful, https://wiki.batc.org.uk/RPi_Test_Card
I have some firmware I wrote for an Atmega328 to control the PLL, PA cooling fans and other stuff if it's any use to you.
Yes I saw your line up and go back to your article, no good re-inventing the wheel
Was very lucky with a rare 3.4Ghz filter on EBay ~ 250Mhz band pass, but like your filter build.
Building in electrical equipment box, old Dell 12v 60A psu case and fan with speed control, pulling air from top of cabinet.
Thanks for the firmware control offer, will see how my effort works out.
Pics to follow as I progress.
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Good find on the filter - be interested to hear more about that.
OK about the firmware, we also have DTMF control using another Atmega - one for encode and another for decode.
The control logic is yet another ATmega which controls which rx gets routed thru to the tx and finally there's a pi zero generating test card captions.
RLC ELECTRONICS F-10842 9619 Marked 3.4Ghz Fc ~ 250Mhz Bandpass.
http://www.rlcelectronics.com/products/ ... lters.html
I did some "very rough" external measurements totally sealed, 5 rods by the look of it, and used calculator on...
https://www.changpuak.ch/electronics/co ... signer.php
In practice cleans up and good signal out.
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Will be running at more like 5w or so out.
Next to put in box and add DTX-1 fitted on door, PSU wiring, over temp cut-out removing 5v from Stealth SM3437, turning off P.A.
Also a separate speed control for Cooling tube fan.
Other control systems to follow, mainly in Rx box.
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The fan fitted in the old stripped out Dell 750W case to blow air through the Cab sucking in fresh from LH bottom of box.
Bottom grills yet to be fitted.
Fan has speed V temperature with sensor clamped to heat sink. Also over temperature set to cut 5v supply to P.A on second sensor.
The only control in the Tx Cab is a relay for remote control to switch off the P.A when requested as per NOV.
Also to provide a Tx sleep mode, yet to be decided.
When on the air it will be running at a modest 5W or so.
GQ should be on air by the weekend at it's temporary location while waiting for news of possible new site.
P.S have found a very old 3.4Ghz circulator, yet to test, also brought out to front Forward-Reflected connections, yet to play with...
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When GB3GQ Txing into slotted waveguide, SWR not effected by pipe with equipment available.
Checked old 3.4Ghz circulator, switches to dummy load port when antenna SWR persuaded to go high
Transmitting from Adalm Pluto into antenna at low signal levels, Rxing on Sat Receiver, tested for pipe attenuation, no loss perceived.
And wouldn't a compact Pc, Pluto, filter and Pa make a great standby / Repeater Tx
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