As a result of a conversation with Andy G1HBE and John MW1FGQ at the start of 2009, I became interested in 13cm narrowband operation (my only previous operation on this band was with wideband FM-ATV equipment).
My first step was to acquire one of the Chorus MMDS downconverters which Andy was using.
This has a PLL-synthesized LO, which I moved down to 2176MHz to
create a 2m IF (the modification entailed changing the reference crystal
to 8.5MHz, and adding a small capacitance to the VCO tuned circuit).
The first signal which I received using this was the 16th harmonic
of my 2m handie, just to check that it was working! But as my home QTH
is surrounded by higher ground, I thought that all my 13cm contacts would probably be
made when operating portable from the nearby hills.
I recorded my first success on 24-Jan-2009, when I received MW1FGQ's
NBFM and USB signals at 59+ from Winter Hill, at a distance of over
60km.
John was using just a few hundred milliwatts into a selection of home-made antennas, and we used 4m FM for talkback.
I've since tried to hear him from home, but with no success.
Then in 2010 I modified the internal "hairpin resonator" RF filters to extend their passband further into our Amateur band (they were originally designed for 2.5GHz of course). Having done this, I was delighted to hear a thumping signal from GD0EMG during the May contest weekend.
And then in June 2010, I managed to pick up John's 0.5W signal from my home QTH in the centre of Bolton.
I had my homebrew 24-ele loop-quad at the top of my mast, with the downconverter hanging below it (in the plastic bag!).
The other aerial is my homebrew 12-turn helix for 23cm.
I was also able to hear a faint signal from G8DTF, reflected from some of the tall buildings in the centre of Manchester.
And finally, on 12-July 2010 (nearly 18 months after our first
one-way test), I managed 2-way QSOs on FM and SSB with John MW1FGQ from
Winter Hill, using an old G8LMW transverter which had been donated to the Bolton Wireless Club by Bob G8DTF.
I'd just re-built this transverter into a fresh enclosure, but its output was only around 10 milliwatts!
I continued to have problems with this transverter, so for the start of the new 13cm UKAC Contest
in 2011 I brought my receive converter back into action, to see what I
could hear from my home QTH in the centre of Bolton. I thought that I'd
struggle to hear anything at all, but as well as hearing Bob G8DTF no
matter where he was beaming, I also got strong signals from Tony G4CBW
near Stoke.
But the biggest surprise was to hear G8OHM in Birmingham
and to detect a CW signal from G0MJW near Oxford. The latter signal
came via an aircraft-reflection, and I could see the Doppler-shift
receding by nearly 200Hz in 20 seconds:
Then in the Feb-2011 session, I also heard MW1FGQ, GW8ASD, G0MJW (Oxford), G8OHM and G3VKV (Cheltenham) all on SSB.
I got the transverter back in action and took it out portable over the "summer" sessions, usually making 5 contacts with the meagre 50mW output.
Then in September 2011 I acquired some more G8LMW boards to make up a transverter of my own.
For the first few months I was using the G8LMW unit for transmit
and the MMDS downconverter on receive, with separate antennas and IF
radios - so I needed to listen on headphones to net my transmitter onto
my receive frequency (a bit like working through a satellite
transponder!).
And thanks to Bob G8DTF, I was able to add a "PA" with around 2W
output, so I was actually able to make a few QSOs from my home QTH in
UKAC sessions - which contributed to my Runner-up Certificate for the
2011 event!
By June 2012 I'd got the RX side of my transverter working, and so was back to the sanity of a single IF radio!. Initially I was just using a satellite "cable booster" as my receiver RF section, but have now cobbled together a better front-end.
But in September I found that I could get a big improvement by adding
a post-mixer gain stage (in the 2m IF) of the transverter, and now I
can hear some more distant signals. This was very helpful in the October
SHF UKAC session, when I was able to work G4BEL (220km), G4KIY (192km)
& G8OHM (134km) all within half an hour!
And I contined to use this throughout the 2013 UKACs - from home in
the darker months and out portable from the hills over the summer.
Then in 2014, following OfCom's Release of part of the band and the subsequent shift of the 13cm UKAC sessions into the night-time, I gave up portable operating myself and loaned my gear to John G8PEF, who was becoming keen on SHF for the first time.
In December 2014 I obtained a Notice of Variation to use the new allocation of 2300-2302MHz. Then in 2016 I began experimenting with an SDR transceiver for use there and in our original 2320MHz band.
In 2019 John returned my LMW transverter. After using it with dual antennas again for a few months, I finally got around to rebuilding my masthead LNA to include an Axicom HF3 relay, so now I can share a single antenna for Tx & Rx (but still keep two downleads to connect to my transverter).
When I first tried this, the preamp was oscillating - but I soon managed to tame it by adding a couple of brass pillars inside the box, to improve the grounding around its input.
Having the same antenna for both Rx and Tx has made it much easier to peak up on other stations: living in a valley, I find that a lot of my contacts are via reflections, rather than on the "correct" beam-headings!
If you'd like to try a sked on 13cm, then please get in touch.