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Cool! Now I can Blog!

March 18th, 2012 | Posted by G4BAO in General - (0 Comments)

Really I can!

Checked out the other three 144MHz band III 400W PA conversions today, all going well. Just one scary moment when a tantalum electrolytic exploded, but no major Damage, just a bit smelly.

Had a look at the combiner as well and worked out how to split it and move it down to 144MHz, but I need some quarter inch 75 0hm PTFE cable (RG302) to do the output combiner; I don’t think my RG179 will take 800Watts! Can anyone help?

73,
John

Those who follow @g4bao will know that last week I checked out the first of our modified Band III 400Watt modules on 144MHz. It produces a mouth-watering (and linear) 400Watts PEP with 10 Watts in, and has “a bit to spare” (No Gavin, that does not mean we can overdrive it and blow it up!)

Today, I modified the other three modules and plan to check them out tomorrow or Monday. I then have to look at producing two pairs of “two in to one” RF splitters and  combiners from the pair of “four in to one” units that came with the original 1500W 4-bay amplifier. Watch this space for progress.

The 10GHz system has been checked out in the workshop and is ready to air test. Currently it is sitting on a tripod in my garage. The current plan is to take it out in Flossie next Saturday lunchtime and run it up on air. To this end, we need two runs of RG58,  one BNC to BNC and one BNC to N plus enough decent 12V cable to go from the van to the top of the mast to ensure that we still have at least 13 Volts up top when it’s taking 10 Amps.

We have already been asked for 10GHz skeds by stations in three  DXCC call areas, with promises of activity from G, GM and GI, all this before we’ve done any publicity in the Microwave fraternity. Contact john@g4bao.com if you would like to arrange a sked on 10GHz. Talk back will be on 144.185MHz and Internet permitting, via ON4KST.

73
John

Microwaves on Mull!

January 31st, 2012 | Posted by Gavin, M1BXF in General - (0 Comments)

If all goes according to plan (and see from the picture that the transverter needs some work still), we will be taking a state-of-the art 10GHz system to Mull.

It will consist of a DB6NT transverter driven at 144MHz feeding a Micom 10 Watt SSPA and has a GPS locked G4HUP DFS Local oscillator. The antenna is a 60cm "Sky" dish with a W1GHz dual band horn feed.

John_G4BAO_10GHz

Most of the parts for this equipment have been kindly loaned by UK Microwave group awards manager Dave Powis G4HUP, in return for me assembling them so that he can later use them from home.
10GHz will be a challenge from Mull as it is far from any activity centres but with suitable conditions and enough publicity I hope to make a few QSOs. I for one will be praying for rain so we can do some rainscatter, but with the right stations we may also be able to do aircraft scatter and normal tropo contacts.

I’ll keep the website updated as the transverter build continues.

73
John G4BAO