Wednesday, 20 September 2017

10 Contacts on 24GHz, including a VK!

On Sunday 17th September it was the third 24GHz/47GHz/76GHZ UK Microwave Group contest. After proving my loan gear worked with Dave G1EHF, I was determined to try and work some stations and learn a bit more about 24GHz propagation and operating on the higher bands. I'm fascinated by discovering how different the band performs compared to 10GHz.

None of my local sites near Reading that are within 15 to 45 mines drive were going to be good enough for 24GHz, so I decided to venture west over to Swindon about 1 hour and 15 minutes drive from Wargrave.  My plan was to try and work Roger G8CUB/P, Chris G0FDZ/P and Doug M/VK4OE/P who were going to be on Hackpen Hill just south of Swindon.  

24GHz Contest roving locations

The prospect of working my first VK on 24GHz was particularly appealing even if Doug was actually in the UK!  My plan was to provide some “local sport” for these 3 stations, in-between them working long distance over to GW-land.

Location 1 - G1DFL/P at Yattenden A4 
near Cherhill Down (IO91AK) 
looking NE towards Hackpen Hill
My first stop was a lay-by just off the Yattendon road near the A4 at Chervil Down IO91AK (577ft or 175m ASL) which is about 9km SW and LOS of Hackpen. After quickly setting up I made contact with the team at Hackpen on 2m just using the FT817ND whip and we moved to 24GHz FM and all 3 Hackpen stations were worked at solid copy and strong signals. I was really pleased to get off to such a good start.

I packed up and drove to the next location Clyffe Pypard IO91BL (594ft or 181m ASL). The spot I chose here was on the top of the ridge near a field gate with fantastic views N and NW. I tried with Martyn G3ZME/P at Brown Clee (IO81LS) but nothing was heard. I swung the dish W and worked the Hackpen trio again at about 5km LOS, but this time signals were much weaker. My location was not in the clear and the view was obstructed by hedges and trees. Some of the QSO’s had to be via SSB but we made it again!

Lots of GHz kit on Hackpen Hill (IO91CL)

Finally I roved to Hackpen Hill IO91CL (879ft or 267m ASL) to a spot about 500m S along the Ridgeway track from the car park. It was great meeting up with Roger and his XYL Sue M6SUA, Chris and Doug. After spending some time admiring their amazing 24GHz, 47GHz and 76GHz works of art, I set-up my 24GHz station (FT790R IF and Nortel ODU 250mW with 30cm dish), nearby just along the path. 

Location 3 - G1DFL/P on
Hackpen Hill (IO91CL)
Everyone seemed to be curious, slightly amused and fascinated by my low-tech tripod mount. I haven’t sorted out a bracket for the transverter/dish (a project before the next contest). So everything sits rather precariously on a white plastic patio table atop my surveyors tripod. This is not great as the whole unit is slightly elevated and also makes pointing difficult. Despite it being very Heath-Robinson, it works!

I tried again with Martyn G3ZME/P but we could not find each other. John G8ACE/P was over at Cheesefoot Hill near Winchester and seemed to work the Hackpen trio fairly easily on SSB. I could hear John and he could hear me but my dish orientation was not helping things so Roger came over and provided some GHz expertise in steadying and pointing, and I managed to exchange details with John at a new ODX and PB of 67km! 

The Hackpen team started to call and work Keith GW3TKH/P and Pete GW4HQX/P on Cefn y Galchen car park on The Blorenge (IO81LS) on all three bands. Pointing W I was really impressed that I could hear both of them at moderate strength with some QSB on SSB at 93km.  I called a couple of times over to Keith and Pete but it was a bit half-hearted as I had to start packing up.  Before leaving I quickly worked all 3 stations on Hackpen from Hackpen to get a few more points, and was really pleased to achieve 10 24GHz QSO’s - albeit 9 of those with 3 stations from 3 locations! 

It was great not to have to use KST, all contacts were scheduled via the Microwave talkback frequency of 144.175MHz SSB. At some points during the day there were several conversations happening at the same time between QSO partners which meant that 144.155 to 144.185 were super busy! My 2M talkback station (FT817ND 100W HB9CV) proved essential for organising skeds. On 2M I heard Noel G8GTZ/P on Win Green (IO80WX) and Neil G4LDR/P on Charterhouse (IO81PH). If I’d have been able to stay longer on Hackpen (or have gone straight there) it would have been interesting to try those paths. 

Must say the 24GHz UKuG Contests are super fun and it was very satisfying to make some QSO's. I plan to venture out in October to have another play.  I may well try somewhere new like Dunstable Downs (IO91RU) to try and work some different stations.

Hackpen Hill is a truly fantastic GHz site and well worth a visit. The Ridgeway path was potholed and very muddy almost needing a 4x4. It was also very busy with about 300 students of Marlborough College hiking past on a 20km charity walk!  I’d love to try 3cm from there. Maybe next time I visit Wiltshire to play GHz.

Two trips in August proved that my 3cm system is broken!

In August I went out twice on 10GHz to compete in the RSGB SHF UKAC, and the August UKuG contest:
  • On Tuesday 22nd August - a 45-minute drive to the Pink Road lay-by at Lacey Green (IO91OQ) atop the Chilterns. It was a cold dark evening and after setting up and impaling my arm on some barbed wire (remember to always take a first aid kit when /P) I set-up the dish and then failed with Peter G3PHO, Dave G4ASR, and Stu G0LGS/P. Stu could just hear me and I could just detect him and Neil G4LDR. Basically I worked no one. Then it rained and I got soaked packing up. 2M talkback signals (I had 6Y and 100W) were massive both ways with G3PHO and G4ASR. I didn't take 13cm as it was complicated enough in the dark with 2 complete stations plus having to deal with KST on my iPad. Sorry to Richard G8FUO who travelled from Windsor to share my disappointment! I learnt once again that GHz is hard, and things frequently don’t go to plan!
  • On Sunday 27th August - I want to my local site near Remenham Hill (IO91NM) for an hour in the UKuG 3cm contest. I was determined to see if I could hear the GB3SEE beacon in Reigate to check my RX. As luck would have it the beacon was off-air. My DB6NT 10 G2 transverter is dead I could not hear or work M0HNA/P at Wilbur Hill and also G7JTT on the South Downs (IO90LX).  
I’ve since sent back both my 13cm and 3cm G2 transverters to Kuhne to get them checked-out and fixed, and to make sure they are operating within spec. I'm hoping to be back on 13cm and 3cm later in September or more likely October.  

Tuesday, 1 August 2017

First QSO on 24GHz!

Really pleased to complete my first QSO on 24GHz last night with Dave G1EHF/P across the car park at The New Inn, Heckfield in IO91MI! Dave’s system is a self constructed transverter using ex-DMC link kit modules producing 100mW into a 30cm dish. I was using a converted Nortel ODU with 250mW into a 30cm dish kindly loaned by Mike G0MJW. 

G1EHF/P on the left and G1DFL/P on the right
After setting up we quickly found each others signals and exchanged 5-9 end-stop reports with our dishes 4.4 meters apart. We then tested with Dave’s Arduino-powered reference beacon to check offset’s again. The QSO was celebrated with a pint in the pub.

Sunday, 25 June 2017

2 Hours and 2 QSO's on 3cm

It was a very windy dry afternoon on Remenham Hill (IO91NM) near Henley-On-Thames, which made dish pointing particularly interesting! I took 10GHz and 24GHz and wanted to try a slightly different site avoiding the lay-by on the A4130 which has high hedges.  I parked near a bridleway/footpath and walked along it into a field until I found a gate that gave clear views. 

After setting up, I quickly found M0HNA/P (Barry G4SJH and Dave G1EHF) on Walbury Hill (IO91GI at 45km) on 2m talkback and their signals on 3cm were very strong. Really pleased to finally work the "Coombe Gibberlets" team on 10GHz after several failed attempts.

We tried on 24GHz but nothing was heard either end. I'm still eagerly waiting my first QSO on that band! I intend to meet Dave and test with his gear at close quarters one evening.

G1DFL/P at Remenham Hill on 24GHz and 10GHz

Next in the log was Neil G4LDR (IO91EC at 70Km) near Salisbury.  I also tried with Noel G8GTZ/P, Stu G0LGS/P and Graham G8HAJ but all attempts failed.  Pleased to get out again on the bands, and add a couple more QSO's to my GHz log!

Thursday, 22 June 2017

Record 6 contacts on 10GHz!

The first UKuG 10GHz Cumulative took place at the end of May, and I decided to return to Lacey Green IO91OQ, high up on the Chiltern Ridge.  This time I was joined by my twin Brother Rob G1TYY, and we met up with Carl M0ICR a friend from the Drowned Rats Radio Club.

Carl and Rob set-up a 4m station for the third RSGB 70MHz Cumulative using my FT817ND,  25W Spectrum Transverter into Carl’s Moxon. Between 3pm and 5pm local time they had fun completing 38 QSO including IO64, IO70,74, 75, IO80-4, IO90-94, JO01, 02, and JO22, working G, GW, GI, GM and PA. 

On 10GHz I set-up the 60cm offset dish on the tripod and for the first time mounted the dish horizontally, so that I didn’t have to optimise the elevation, so one less variable to worry about. It seemed to work much better in that configuration. I’ve not yet managed to re-house and add the LNA and RF amp, so the DB6NT G2 was barefoot with approx 150mW to 200mW out, driven from my trusty FT290R Mk1.  For 2m talkback I used a Trio TR-9000 with a 100W Amplifier into an HB9CV.

10GHz /P at Lacey Green

After setting up, I switched on the 2m Microwave talkback 144.175MHz and the band was worryingly quiet! KST was busy with UK folks trying to work stations in Northern France. First in the log was Martyn G3ZME/P on Brown Clee at 164km (which was my ODX) followed by Stewart G0LGS/P on Cleeve Hill (IO91XW at 96km), both very strong signals.

Mike G6TRM/P (JO01QD at 161km) who I have tried to contact previously on both 10Ghz and 24GHz, was out near Dover and he called me on my phone to try and set-up a QSO.  For the first time ever I heard his beacon to the South East distorted with an auroral-like tone due to RS enhancement and scatter. We quickly completed a QSO which made my afternoon as we have tried several times before from other sites without success. Its all about the location! 

The QSO with Mike was tailgated by Graham G8HAJ (JO01JR at 119km) near Maldon in Essex, the first time someone has called me on 10GHz and he was also a very strong signal but hugely distorted. Graham’s signal was only readable when beaming South East towards Dover, no signal was heard on the direct path.

I also made contact with Noel G8GTZ/P who was at Hannington (IO91JH at 50km) and Matt 2E0MDJ/P who was co-sited with Stewart on Cleeve Hill before packing-up.

3cm Contacts in all directions from Lacey Green!

It was a great couple of hours on 10GHz with a record 6 Contacts completed. ODX was G3ZME/P on Brown Clee IO82QL at 164km. Great to work two stations in JO01 including my first complete QSO with Mike G6TRM/P. Lacey Green seems to be a good GHz site in most directions. The Wx was great, warm sunny with a blue sky and some really interesting rainscatter propagation.  I’m looking forward to returning to Lacey Green later in the year.

Thursday, 25 May 2017

First Outing on 24GHz!

Mike G0MJW has kindly lent me his spare 24GHz (1.2cm) system to test. I've been wanting to find out about the propagation and experiment on the millimetre or EHF (Extremely High Frequency) bands for awhile. I'm super interested in seeing how this part of the radio spectrum performs compared to 10GHz (3cm).

Mike's kit is a Nortel ODU modified from 23GHz which provides a complete "24GHz in a box". An internal relay uses positive volts up the the coax to switch to TX, and 1W at 432MHz generates 0.25W at 24,048MHz. The FT790R Mk1 is an ideal driver radio for this unit. The Nortel power supply requirements are between -36V and -48V, so a DC/DC Converter was used powered from a separate 12V leisure battery source.

On Sunday it was the first UKuG 24GHz/47GHz/76GHz Cumulative and I was eager to see if it all worked! Mike had warned me that the unit had been stored for the past 10 years and there was a frequency offset of +/- 150kc.  So my plan was to test the RX first and then try and find someone local to boldly attempt a QSO with.  Like all of my Microwave endeavours I was prepared for complete failure and hardship.  That way anything positive is a pleasant surprise!

I need to spend some time working out how to fix the unit to a mast.  But for now a small white plastic patio table was utilised to provide a flat surface on top of my surveyors tripod. This seemed to provide a useful workable solution!

First stop was Knowl Hill IO91OQ about a 10 minute drive from my home QTH. I decided to visit a site north of the A4 which is higher than an alternative site just to the south.  The location is accessed from a footpath and presents a SE to S facing hill. I quickly set-up in a field of sheep. The first objective was to try and find the Reigate beacon GB3SEE (62km to the SE) to test the RX and to find the frequency offset. The transverter RX seemed to be working as there was a healthy increase in noise, and on TX a reassuring clunk of the relay! However, after significant sweeping of the band up and down, and pointing the dish to where the beacon should have exactly been on a direct path, nothing was received? This was disappointing but you have to be thick skinned for all this microwave lark, see my other blog posts about 10GHz!  Whilst onsite Mike G6TRM/P in JO01QD (162km to the SE) near Dover phoned me. We tried to complete a QSO over what would have been a very marginal heavily obstructed path,  but nothing was heard.  We are yet to make the path go on 10GHz, so 24GHz was somewhat optimistic!  However, its always worth a try.

24GHz from Knowl Hill, looking SE

The 2M Microwave talkback frequency 144.175MHz was busy with chatter. With just the FT-817ND and a 2m/70cm Whip antenna Keith GW3TKH/P on Blorenge (IO81LS) and Roger G8CUB/P with Neil G4LDR/P on Hackpen (IO91CL) were all loud. Martyn G3ZME/P on Brown Clee (IO82QL) was also heard looking for QSO's. So I decided to drive the 35 minutes to Christmas Common (IO91MP) about 850ft ASL on the Chiltern Ridge. After a quick "CQ Microwave Contest" on 2M I found Neil G4LDR/P who was still on Hackpen (60km to the W). We tried a couple of times on 24GHz but with no success. The Wx was hot and sunny (with no obvious humidity problems) and the views at both locations were amazing, which made up for the lack of QSO's!

24GHz from Christmas Common, looking NW

It was great to get back out again /P. I plan to drive down to Reigate and park up next to the GB3SEE 24,048.9600MHz beacon to work out the exact frequency offset of the Nortel unit - before the next EHF UKuG Cumulatives in June, September and October.

Wednesday, 29 March 2017

First 3cm QSO in 2017

It was a clear dry evening last night at 8.30pm in the March SHF UKAC and I set-up both 13cm and 3cm dishes on the tripod at Remenham Hill, my normal /P perch in IO91NM. This is a roadside layby just north of Wargrave, with clear views of the horizon in all directions.  Quickly I worked G4BRK and G4LDR on 13cm SSB.  But 3cm remained very quiet.

For the first time from this QTH I managed to find the GB3SEE Reigate Beacon on 10368.850MHz. It was weaker in strength than from some of the other sites I use nearby, Remenham Hill must be obstructed to the SE.  It was good news finding the beacon, it meant that I could work out the approximate offset of my transverter, which was calculated to be about 22.3KHz high of the dial frequency on the FT-290R.

With my frequency better defined, I tried again on ON4KST with Neil G4LDR in Salisbury and we managed to work each other on 3cm. Neil's signal was very distorted by rain scatter from a set of rain clouds that were between us, moving my way from the SW and W!  Rain scatter produces a profound doppler shift with signals moving up and down in frequency and on SSB this sounds almost auroral. The rain clouds last night were moving quickly towards me and the scattering effect meant that it was difficult to resolve Neil's signal, but we managed to complete a 3cm QSO with RS helping. My first 3cm QSO in 2017.

At about 10pm the rain arrived overhead and I got absolutely soaked!  I did manage to hear M0GHZ and G4BAO on 3cm before packing away, but my 150mW was too QRP for them to hear me. Fortunately no water got into the transverter boxes and everything is back in the shack drying out, ready for another outing in next months event!