GPS and HF Splitter

Home Up 70 cm 250 Watt PA mast at remote mast at qth 47 GHz new system vsat alford loop GPS and HF Splitter Perseus GPSDO repair measuring equipment Cloudwatcher Radio Direction Finder fountain

After introduction of several GPSDO's in my shack and also a HP Z3801a as reference oscillator on 10 MHz I saw a large increase in GPS antenna needs.

Then I also added two Kiwi receivers in my shack and I decided that it was time for a GPS antenna splitter

My demand for GPS antenna outputs was for minimal 7 GPS receivers.

I searched the internet for some available splitters but did not find a suitable GPS splitter without compensation for the splitting losses.

Then I decided to try and build one myself.

The splitter I made is based on a available and quite cheap 8 times splitter using F connectors
This splitter is available on, search for: Verteiler Splitter 8-Fach 5-2400MHz SAT DVB-T2


Bild 2 von 5

and to compensate for the splitting losses a small in line amplifier for sat TV running from 950 until 2250 MHz with 20 dB gain

As antenna I am using an active antenna mounted in my antenna mast at about 6 mtr high.


In the combination using the in line amplifier I first tried to use the tele-supply feeding as designed in the amplifier combined with the dc feed through from the splitter.

This was not successful, the GPS receiver sending only 3.3 Volt to the inline amplifier and the active GPS antenna was not enough for the amplifier and thr active antenna to work.


I decided to open the in-line amplifier to see if I could modify it sending 5 Volt to my active GPS antenna even when there are no receivers attached.

This in-line amplifier must be fed with 15 Volt DC

I modified the amplifier, at the DC line from the amplifier I made two interruptions in the DC line (at the red lines in the above picture).

I drilled a hole at the side of the box to add a dc feed through capacitor from 1 nF.

At the position of the right red interruption I mounted a 5Volt regulator 78L05 to lower the supply voltage from 12 to 5Volt,
the 5 Volt is then fed through the coax cable to the active GPS antenna


I tested this with a GPS handheld receiver to see if the signals passing through

This was working perfectly for my needs, the GPS signals on the different outputs were strong and reliable.


The GPS antenna mounted in my antenna mast


GPS coverage as recorded by my Kiwi receiver


HF antenna signal splitter

I made a same setup for my HF active antenna with Alford loop.

Up to now I had been using several 2 or 4 way splitters behind each other to connect to total 6 receivers in my shack.

This was not very stable, suffered from bad connections from the F type, and also the frequencies below 5 MHz were suffering high loss and loss variations. I decided to use a similar setup for my HF splitter using a small amplifier in front of this divider

Both splitters were mounted on a board of trespa, to be wall mounted

I made some transitions from F to SMA male to connect directly two Bodnar GPSDO's to the splitter


The two splitters in use, left for GPS signals with two Bodnar GPSDO's mounted, one for 10 MHz reference and one for 80 MHz for my Perseus receivers,
On the right the splitter for the HF bands, working from 20 kHz until 40 MHz.