VA3TO 47GHz Portable Station
(Mounted above 24 GHz)
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Ver. G1 | Ver. G2 | G2+PA | Dish
Dish: 12" NURAD prime focus with integral Cassegrain feed.
Transverter: DB6NT/Khune MKU 47 G2 transverter. 89 mW o/p power with internal LNA.
Local Oscillator DB6NT/Khune 8-13 L.O. @ 11.736 GHz, Bliley 10 MHZ OCXO reference. (L.O. is remote mounted in 24 GHz Box).
LNA: Internal 19dBg, 6dB NF.
PA: 1W Kuhne MKU PA 6MM-1W A.
Waveguide Switch: Logus LM28BSL with custom made WR-28 to WR19 flanges.
I.F. Rig: Icom IC-705 @ 144 MHz.
Accomplishments to date:
MKU47 G1 Distance (Tropo): 104km - VA3TO in grid FN03BI to VA3ELE in grid FN03AU (150 uW !!!)
MKU47 G2 Distance (Tropo): 220km - VA3TO in grid FN03DF to VA3ELE in grid FN13KU
MKU47 G2 Distance (Rain Scatter): 132km - VA3TO in grid FN03CF to VA3ELE in grid FN03RX
MKU47 G2 Distance (Snow Scatter): 125km - VA3TO in grid EN92MV to VA3ELE in grid FN03DM
47GHz VUCC: 7 Grids from grid FN03CN.
In the fall of 2019 I acquired a DB6NT/Khune bare mixer MKU 47 G transverter with L.O. , a great addition to my 10 and 24 GHz Microwave Rover lineup. I wanted to avoid having to lug around a third station on a tripod so I came up witha scheme that could be quickly added to the 24 GHz rig and easily removed for transport. I often go out with 10 GHz only and contesting is either 10 GHz only or 10 GHz & Up so it made sense to add it to my 24 GHz rig. The bottom edge of the aluminum frame for the 47 GHz assembly slides into a clip on the 24 GHz NEMA box and a handscrew firmly fixes it to the 24 GHz dish.
First Tests on 47 GHz:
On a bitter cold January 1st, 2020 I set up at FN03DF and tested with Peter VA3ELE at 4 different locations. The first was 20 km across the west end of Lake Ontario from Hamilton to Mississauga (Ontario) and we were both S9+. Then Peter moved east to a location 40km away and again we successfully completed with strong signals. Peter moved further east to a spot 53 km away. Signals were not quite as strong but still an easy contact. Peter continued east to a location about 108 km away but unfortunately there was nothing heard at either end on 47 GHz despite our S9+ signals on 24 GHz.
Observations for my first time out:
- Free space attenuation is very noticeable at 47 GHz.
- The free running crystal controlled Local Oscillator drifts quite badly, especially in the sub freezing temps we were operating in. The drift at 122.25 MHz (base oscillator freq.) is multiplied by 96 then again by 4 so it is quite prevalent at 47 GHz. An improvement in L.O. stability is in order.
- The limitations of using a bare mixer transverter with no PA or LNA have been realized.
- During the 2020 Microwave Spring Sprint I managed to break 100 km (104 km) with Peter VA3ELE. I was set up at FN03BI in Fonthill, Ontario and Peter was in FN03AU near Caledon, Ontario. There was very little signal indication but the copy was perfect on my end. Pretty impressive for 150 microwatts into a 1 foot dish and no LNA. Video here:
VA3TO 104 km on 47 GHz
- A DB6NT L.O. 8-13 PLL Local Oscillator ref-locked to a 10 MHz OCXO has been integrating into my 24 GHz rig along with switching that also feeds the LO signal to the 47 GHz rig. The old crystal L.O. has been removed and a connector added to bring the OCXO Ref Locked signal from the DB6NT 8-13 L.O. located in my 24 GHz box in. What a treat... right on frequency and no more drift !
- In the summer of 2021 I upgraded the transverter to a DB6NT MKU 47G2. It offered a lot more power (89 mW) and an internal LNA which is a nice upgrade from the old 150 uW bare mixer setup. It took some fancy waveguide bends & twists and some custom made brass flanges to keep it all compact. My first test was on Aug.15/21 with Peter VA3ELE... S9+ signals both ways at 41 km.... looks promising !
- On Jan.02, 2022 me and Peter VA3ELE successfully completed a 117km 47 GHz Snow Scatter contact. I was set up in FN03DF and Peter was in FN03QV. Both of us were running DB6NT MKU 47 G2 transverters with the 8-13 L.O. I have 89mW into a 12" Nurad dish while Peter has 85mW into a 24" dish. Video from my end here: VA3TO 117km 47 GHz Snow Scatter
- Grids #4 & 5 ... 47 GHz VUCC !
On April 4th, 2022 I completed 47 GHz VUCC after begining the challenge 9 days earlier. Thanks to Peter VA3ELE for Grids FN02,FN04, EN93 & EN94, and to Kevin VE3KH for FN03 ! Several of the grids were attained using rainscatter as there are no unobstructed paths between FN03cn and those grids. Normally the humidity in the air on a rainy day is a killjoy on the higher bands but we discovered that aiming up into low ceiling scattered rain for relatively short range contacts actually works. This was a new revelation for us and perfect for working blocked path adjacent grids to achieve VUCC !
- Our new Tropo Distance Record @ 220km !
On April 30th, 2022 Me and Peter VA3ELE decided to take advantage of the low dewpoint before the summer humidity kicks in, so we spent the morning attempting to break our previous best distance record (104 km) on 47 GHz.
I set up at FN03df on the Niagara Escarpment at the west end of Lake Ontario and Peter started on the north shore to the east in FN03vw at a distance of 150 km. That worked very well so he kept moving further east to FN13ax @ 167 km, then FN14da @ 184 km, and finally FN13ku @ 220km.
We really had to work for this one... 40 more km's than the last stop and the QSB was very deep and slow. It took 7 or 8 minutes of exchanges back and forth to complete but we did it ! I didn't get a single full video from my end on that one... I stopped and restarted too many times hoping to capture a complete QSO, but the QSB nulls were long and deep so I only ended up with a snippet of video for that contact. The RR's & 73 came in a later exchange.
184 km on 47 GHz CW/SSB/FM... full video here: 184 km on 47 GHz
220 km on 47 GHz CW... video snippet here: 220 km on 47 GHz
- Grid #6 !
On May 3rd, 2022 the weather forecast was calling for scattered rain in the afternoon so Peter VA3ELE drove down to Grid EN92xx near Hagersville Ontario to see if I could get another new one on 47 GHz. As usual we peaked up on 24 GHz then switched over to 47 GHz. After a quick exchange of dashes to tweak the dish elevation for maximum signal we quickly completed the contact. Video here: Grid # 6 on 47 GHz !
- In late May 2022 I decided to buy a Kuhne 1W PA for 47 GHz. This was by far the most dollars per watt that I've ever spent on an amplifier but with looming rumours about the sale of Kuhne and the future of it's Amateur line, I decided to get one while they were still available. Once it arrived I integrated it into my system then did a short function test with Peter VA3ELE and all seemed well.
- Grid #7 !
After a couple of previous failed attempts on days with high humidity (fog) or equipment problems, I managed to score FN12 for grid #7 on 47 GHz. We waited for an evening with low humidity/ dewpoint as well as convection enhanced tropo at dawn, then Rus K2UA went to FN12fs and I set up in my usual spot at FN03cn. We first peaked up on 24 GHz with S9+ signals then switched over to 47 GHz and Rus heard my dashes right away. We repeaked then completed the contact on SSB but the QSB was quite prevalent so we went back to CW for the Video: Grid # 7 on 47 GHz !
- New 47 GHz Rain Scatter Record @ 132km !
On Friday December 16, 2022 me and Peter VA3ELE broke a new Rain Scatter record on 47 GHz at 132km. The forecast on Thursday was calling for rain or snow (temps hovering around 0°C) the next morning so we decided to try it before going to work. I used Google maps and a surface elevation tool to search for a location for me that would provide a good shot to the east at a decent distance. I settled on going to FN03cf, up on the Niagara escarpment in Hamilton, Ont. about 50 minutes SW from my home. Peter drove 90 minutes east to FN03rx in Orono, Ont. It turns out that location has some elevation too so our path was pretty clean, most of it over Lake Ontario.
We arrived at our respective sites and set up at around 7:00 am. It was snowing at Peter's end and it had just stopped raining at my end. A look at the weather radar showed that it was raining for the majority of the path inbetween. We started off on 24 GHz and instantly found each other. Our CW signals were not all that strong, about S2 ~ S3 R/S but an easy copy. After completing on 24 GHz we switched over to 47 GHz and signals were down in the noise. We spent a few minutes dashing back and forth and adjusting the dish Az & El to get something to work with then made the contact. No signal level at either end but the rainscatter CW was readable and good enough to complete !
Video from Peter's end here: 47 GHz Rain Scatter Record !
47 GHz Grids Worked from FN03CN
(Tropo contacts = Yellow dot, Rain Scatter contacts = blue dot.)
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