VA3TO 5.7 GHz Portable Station


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Front | Internal





Equipment details:

Dish: 24" prime focus mWave with Dual Polarity linear feed.
Transverter: DB6NT/Kuhne MKU 57 G3.
PA: Alcatel 3DH03218AC (from MDR8000 system) w/ VA3TO bias/control board. ~8 Watts o/p.
PA 10V Supply: VA3TO high current, low dropout linear regulator board.
Sequencer: AD6IW 3 event sequencer.
RX/TX Antenna Switch: Ducommun 12V SMA latching relay w/ W6PQL latching relay driver.
10 MHz Reference OCXO: VA3TO OCXO board w/ Bliley NV47A1282 module.
I.F. Rig: Icom IC-705 @ 144 MHz.


Accomplishments to date:

Distance (CW - Tropo): 214km - VA3TO in grid FN03an to W2FU in grid FN13he.



With local interest in the 5.7 GHz band gaining traction (spring 2026) and the growing popularity of the Icom IC-905 transceiver which covers this band, I though I would build up a portable station to stir up some activity and try to add another band to my VUCC accomplishments. I already had a Kuhne MKU 57 G3 transverter that I purchased several years ago. I had made a few contacts using it barefoot (250mW) while lashed onto the back of a panel antenna to give out points during a couple of past VHF+Up contests, but it was a very temporary setup so it was time to build a proper rugged portable system with some gain.

I started building the new system in the middle of March and completed it in time for the next Microwave Activity Day ("MAD") on April 4th.
A commercial 2 foot dish with feed was acquired from my friend Neil, VE3SST. I had to mill some protrusions off the aluminum mast mounting bracket so that the enclosure could be mounted flush to the back of the dish. I like my gear to be weather resistant since I sometimes operate in the rain and snow so I ordered a hinged waterproof box from Amazon. The box is relatively small for the amount of equipment inside (11" x 7") but I'm getting better at making things more compact through the experience of my previous builds. I got the Power Amplifier from another friend Rene, VE2UG who purchased it several years ago off eBay when there was an abundant supply of these surplus Alcatel MDR8000 PAs available for very reasonable prices. I built up a bias/control board for it, set the bias voltages for the 3 devices and it delivers upwards of 8 watts... a big improvement over the barefoot transverter.

Sadly, the 5.7 GHz Amateur band is shared with WiFi and ISM services so some hams have experienced interference on this band. Anticipating some noise from these services, I will try my system without an external LNA to start since the transverter front-end is spec'd to have 20 dB of gain with a respectable noise figure of <1 dB. I have a couple of different 5.7G LNAs to try if I find that the receiver is a little deaf. I also have a bandpass filter to put inline if WiFi and ISM interference is problematic although it may prove not be very effective if most of the noise is in-band. All to be discovered as I explore this new-to-me band.



Updates:

Grid #1 VA3TO FN03cn - WA3PZQ EN92wd.
Grid #2 VA3TO FN03cn - VE3KH FN03cg.

During Microwave Activity Day on Saturday April 4, 2026 I was able to test the new rig out and made my first two contacts.
I first worked Paul WA3PZQ in EN92wd near Erie PA on 10 GHz, then we switched over to 5.7 GHz for an easy contact at 192 km. Later on I worked Kevin VE3KH with a big signal at just 31 km away.
The new rig seems to be working well and I did not experience much receiver interference on my first outing. It did however almost blow over a couple of times during high gusts of wind. I now realize the camera tripod I am using is a bit too light for the job so I will get a more heavy duty tripod.


Grid #3 VA3TO FN03cn - N2JMH FN12bw.
Grid #4 VA3TO FN03cn - W2FU FN3he.

On my way home from work in the afternoon of Friday April 10, 2026 I stopped off at FN03cn and worked N2JMH for EN12 then W2FU for FN13. Both contacts had the assistance of some rain scatter.
I pre-arranged these skeds in the days leading up to the attempt. Thanks to Jim and Jeff for getting on the air.


5.7 GHz VUCC (4 Grids).











Grids Worked from FN03CN
(Tropo contacts in yellow, Rain Scatter contacts in blue.)





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