My first 47GHz UK QSO

Having put the 47GHz system in a box it was time to try it out. An opportunity arose with the upcoming 47/76GHz contest so a visit to Cleeve common IO81XW was organised

As GW3TKH was going portable on the Blorenge IO81LS I Initially set up on the west side of the summit. We first tried on 24 GHz and signals were huge both ways on NBFM with both GW3TKH/P and GW4HQX/P. Moving to 47GHz signals were equally loud on NBFM  both ways with GW3TKH/P but I had to resort to SSB to work the GW4HQX/P QRP

47 GHz transverter on top of 24GHz Transverter

47GHz takeoff towards The Blorenge

 As there were no others on 47GHz I packed away that band and went manportable on 24GHz from the trig point and worked another 5 stations including the best DX of G8GTZ/P at Walbury at 74km to achieve 3rd overall place

My First 76GHz UK QSO

 Having assembled the transverter in a box as described here it was time to try it out. An opportunity was  found with the upcoming 24GHz to Light contest so an outing was made to visit Cleeve common. As the weather was going to be good it was decided to visit the trig point IO81XW90 with its good all around coverage.

qsos were easily had with GW3TKH/P amd GW4HQX/P when using the 12" Procomm dish

Housing the DB6NT 76GHz Transverter

Having also bought a DB6NT 76GHz transverter recently I decided it was time to be put in a box and join it's 47GHz cousin in the field.

It was found that the same size box as used to mount the 47GHz transverter would be suitable. However,  how to get RF signals in and out would be a challenge. After a long search a pair of 90 degree WR15 H plane bends were found on Ebay. They were similar but not identical in dimensions. These would allow the transverter to be mounted on the base of the box with the waveguide bends poking through holes in the sidewall.

The box was fitted with a an N type socket for the IF and a TNC socket for the 10MHz reference. A 3 pin XLR was used for the 12V power. A power LED,  lock LED and transmit LED were fitted

The local oscillator was mounted directly on the base of the box alongside the transvreter. As the 76GHz portion of the band used in the UK is 75976 MHz and the transverter has a 144MHz IF the local oscillator was programmed for 9479 MHz. Note that this is not an available standard frequency available in the MKU oscillator. I chose to reprogram the unit and replace the existing 9486 MHz 76 GHz LO with the 9479 MHz one.

The transverter has an RF output power Indication  which was connected up to my usual LM3914 and 10 LED bargraph indicator. Initially this was mounted inside the box on the local oscillator but it was found after its first outing to be more useful if visible from the outside ao a hole was filed and the unit mounted.

Housing the DB6NT 47GHz Transverter

 Having bought a DB6NT 47GHz transverter last year I decided it was time to use it, especially as I had a pair of W1GHZ horns that would avoid the need for a T/R relay.

Finding a big enough waterproof box for the xverter module was an issue but one was eventually found that was a close fit. It mounted fine in the box but the SMA plugs on the ends made it too long. Using a dremmel some of the inside walls of the box  were removed and it just fitted, even if the SMA plugs could not be unscrewed in situ!

The transverter was mounted "labels down" on flat base of the box with holes made to line up with the TX and RX waveguide ports

The local oscillator was mounted directly on the base of the box alongside the transverter. As the 47GHz portion of the band used in the UK is 47088 MHz and the transverter has a 144MHz IF the local oscillator was programmed for 11736 MHz. which is one of the available pre-programmed frquencies

The box was fitted with a an N type socket for the IF and a TNC socket for the 10MHz reference. A 3 pin XLR was used for the 12V power. A power LED,  lock LED and transmit LED were fitted.

The transverter has an RF output power Indication  which was connected up to my usual LM3914 and 10 LED bargraph indicator. Initially this was mounted inside the box on the local oscillator but it was found after its first outing to be more useful if visible from the outside ao a hole was filed and the unit mounted

BATC 2020 146/437MHz Contest

 BATC announced a dual band 146/437 Dualband DATV contest on August 8/9 . Dorstone IO82LB was the obvious choice but due to other commitments only operation on Sunday 9th was possible. As G3UKV would be out portable on 5GHz FMTV equipment for that band was also taken

G8GKQ/P was easily worked on both 2m and 70cm IO81UC 118km. I could see his 5GHz FMTV signal but he could not copy my 8W signal.

My signals were successfully received by G3VKV (IO81XV) at 71km

M0YDH/P (IO82QL) was worked on both bands  along with G3UKV/P at the same site on 5GHz FMTV at 54km

G4CBW/P (IO93AD) was worked easily on 432MHz but it took 25 minutes to complete the QSO on 2m due to QSB at 141km

Finally my signals on both bands were received by G4NZV (IO82WA) at 63km. An interesting outing

The equipment on 144MHz was a Portsdown 2019+ 30W Mitsubishi brick to a 9 element portable tonna at 4m. On 437 MHz a Portsdown 2019 + Mitsubishi 7W brick + 400W LDMOS amp into a 21 element Tonna at 5m

The results  were subsequently published and came as a bit of a surprise with a win and a trophy!

IARU TV Contest 2020

For this years IARU ATV contest I decided to get a bit more active than last years 2 QSOS and go portable at three locations :-

Saturday.

Left home at 0800 and drove the 84 miles from home to Walbury hill IO91GI (thanks to Noel for the opportunity to use the site while he went elsewhere) Having never been there before it was a bit tricky to find, but the photos from google maps Noel supplied helped. 

Having 7 TV bands plus 2m FM talkback setting up the equipment took a long time, At the start of the contest worked G8GKQ/P on all bands 432 to 24GHz at 54km.

Worked G8LES at 40km on 23 and 13cm and he received my signal on 9cm (he has no transmit on that band) 

Worked G8GTZ/P at 51km 432 to 24GHz except 13cm (equipment trouble his end).

Transmitted my signals successfully to G4LDR at 30km on 24GHz to 9cm during some huge rain storms which forced a couple of hasty retreats into the car. Could lock to his carrier on all bands but got no further than Carrier and FS lock.  Did have a two way on 13cm with him

Drove back home arriving at 2240

Sunday

Left house at 0700. Arrived at cleeve common car park IO81XW at 0800 

As a new location the rules said I needed new contest numbers in the Portsdown 2020. No problem I thought, I have previously saved a suitable new set to USB drive. Imported them but subsequently not even the Portsdown touchscreen would respond. After much searching found ethernet cable and did a factory reset via SSH. Manually set all parameters. Lost 2 hours so no time for expedition to trig point for LOS 24GHz path.  Worked G8GTZ/P at walbury at 76km on 13cm to (surprisingly) 10GHz,   Just not enough signal for 24GHz.  Location getting overrun with visitors so left at 1200

Drove the 29 miles to Notgrove, IO91BV, a site that should have a good path to Walbury (and would not be crowded!!) 

The Membury TV mast can be seen through the gap

Decided to change the contests numbers manually and avoid risk. Worked Noel at 67km 23cm to 24GHz. Signals were not too loud on DATV but huge on 24GHZ NBFM.  

Worked G0MJW with big signals both ways on 70cm and 23cms. 

Saw signals from G4CPE on 70cm but couldn’t attract his attention with my 5W Tried getting signals on 70cm to G3VKV but path too blocked locally. Good signals on microwave bands from GB3ZME 3 and 5 GHz but too late to work the M0YDH/P in that area. Did hear the GB3LPC beacon on 3.4GHz narrowband for the first time.

GM3SEK Mains filter finally finished

Having heard about the GM3SEK mains filter at the RSGB Convention 2019 and seen the design on his  web site I had decided to build one. I gathered most of  the necessary parts after Christmas. The one missing item were cable ties with screw holes to hold the ferrites in place. I finally found some on ebay so set about assembling. I decided to fit a 16A chassis mount plug and socket on the box to make it more transportable, the mains input and the distribution panel output having connectors to allow easy disconnection

WKUSB-SMT lockup

I have used winkeyers for many years now, ever since building a serial version board to take on the 3B9C expedition without any trouble. While setting up a WKUSB-SMT at the MW2I station recently it refused to respond after a run on 20m. It appeared on the virtual com port but refused to respond to the wk3demo or wk3tools programs. I thought a reset was needed, but the manual was not very helpful as it suggested hitting the reset button when connected to the keyer, which I could not do. So I left the problem and substituted the spare winkeyer a  WKUSB-DIP which worked fine.

A few days later I found the document  https://www.k1elsystems.com/files/WKUSB3_restart.pdf  on the winkey website which had a very interesting paragraph:-

There have been cases where a WKUSB‐SMT has entered a lock up state due to a nearby lightning strike, a high RFI field, or other very unusual situation. In most cases the WKUSB can be restored to normal operation by pressing and holding the red pushbutton for about six seconds until it responds with an R followed a few seconds later with an OE (dah‐dah‐dah‐dit).

This technique was tried and the WKUSB-SMT recovered. It did reset the EEPROM so all settings had to be re-entered, but the crisis was over!  Pity this information is not in the manual!

The Langstone Narrowband Transceiver with Pluto and RPI 4

At the RAL TV meeting last year G4EML demonstrated a narrowband transceiver ("Hayling") using a raspberry Pi 4 a 7" LCD screen USB soundcard and an Adalm Pluto. Talking to G8GTZ at the recent Didcot Rally I found that the code has been uploaded to github ("Langstone")so on my return from the rally I decided to try it out.

The first attempt at building the code resulted in a no frequency display on the screen. The log seemed to be objecting to my USB sound card, so I changed it for another one I had and I was getting  the frequency readout but no audio

I then noticed that the display seemed to think I was on transmit. I consulted with G4EML and found that there should have been a pullup resistor on the GPIO PTT input pin. With this modification the display indicated RX and i got receive audio and could hear signals

I took a listen to my transmit signal. The dots sounded fine but i discovered the centre button on a 3 button mouse was needed to send CW, which I didnt have. I got no audio on transmit until I discovered the USB sound card mic input needed a computer headset (electret) microphone rather than my (dynamic) heil headset 

To try it out on the air I hooked up a 3W 1296MHz module and had a nice 2 way qso with a local on the band

I mentioned my findings to G4EML who updated the code to have a key input and a PTT output to drive an amplifier. He also added band output pins to auto switch external amplifiers and preamplifiers

I was then interested  to see how the system would work as a microwave IF. I connected it the radio on 144MHz to my 5760 to 144MHz Transverter and could hear the GB3OHM beacon on 5760.9MHz on a horn antenna. I then realised the pluto works directly on 6cm so I connected it directly to the horn antenna and could hear nothing. I then used the KX3 and the transverter to calibrate the Pluto and found there was a 65kHz offset, on which frequency I could just detect GB3OHM. I dug out a DEMI ATF36077 preamp and put that infront of the Pluto and the beacon became quite readable

All that is needed now to make the rig suitable for portable operation is a panoramic display!

CQ160 contest 2020

Having had so much fun in the ARRL 160 contest I returned do the CQ 160 in January from DEMI. To avoid the previous issues with connecting in Charlotte I flew on an American Airlines codeshare flight which was on a BA plane direct from Gatwick to Orlando, arriving early at 1430, Steve and Sandy met me at Orlando and after a fish supper we drove the 3 hours to Live Oak.

The rules for this contest are not quite the same as the classic CQWW rules. Multipliers are US states+VE provinces+countries. Although DX stations (and only DX stations)  send their zone, they dont add to the  multipliers!

The contest started at 1700 local on Friday under the call K0DI. Unfortunately the starting operator was stuck on a plane at the gate in Washington, so I was volunteered to start. Calling CQ for 10 minutes, nothing much happened, then the pileup started, which was a new "run" experience, which I continued for 2.5 hours before switching to mult duties retiring at 2300 I returned at 0600 and operated till the band closed at 0830 working some JA but no VK/ZL

Having not experienced the overnight shift I returned at 2300 to teamup with Steve. I ran , he searched. I ended up running for 8 hours. The band closed around 0800 sunday morning again . We resumed at 1600 that afternoon  after a visit to the club shack and surprisingly had 17 qsos in the last hour

For light entertainment on the monday after the contest we replaced the power supply in a quadra VL1000 amplifier which had been hit by lightening.