3.4 GHz

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The UK 3.4 GHz band (aka 9cms) is 3400-3410 MHz with the centre of the narrow band operating segment at 3400.100 MHz, and DATV usage around 3404-3408 MHz. It was formerly 3400-3475 MHz until the 2014 Licence review which reallocated spectrum for commercial wireless broadband

Band Plan

See the RSGB 3.4 GHz band plan for full details.


There are a number of narrowband beacons in the 3.4 GHz - see this page for an up to date list.

TV Repeaters

There are an increasing number of amateur TV repeaters with DATV outputs in 3.4 GHz - see this page for an up to date list. There are no licensed voice repeaters in the band.

3.4 GHz Equipment

Several equipment manufacturers make transverters for 3.4 GHz:-

  • DB6NT
  • Anyone else?

A few years ago there was a lot of surplus 3.4GHz wireless broadband equipment available - you don't see some much now, but if available it can be easily converted to DATV operation.

G6gvi9cm.jpg Photo from G6GVI web page

The Airspan AS4000 is an outdoor consumer unit operating in duplex mode (Tx and Rx) on 3.4 GHz - it needs DC supply, transmit IF and reference oscillator up the co-ax and sends rx IF down.

The unit IF is at 820 MHz and G6GVI and M0DTS have both modified the local oscillator by changing the reference oscillator and reprogramming the PIC to provide an IF at 1296 - power output is 100 - 200 miliwatts with no modifications.

However, it is now possible to just use the ADF4351 controlled by Ron G7DOE's simple controller to provide an LO of 2970, which provides an IF at 432 MHz for Narrow Band and DATV use. The only other mods are to apply the IF signal after the 800 MHz IF filter and key the transmitter as shown on M0DTS site.

Link to G6GVI page

Link to M0DTS page

Ionica PA


Surplus units which require absolutely no modification to produce 15 watts NB or 5 watts DATV when driven by the AS4000

Link to GM4ISM page show how to use the Ionica PA

Ionica Big boards

Bb1.jpg Photo from G4BAO web page

Whole chunks of working circuits can be retrieved from the Ionica main board to make a simple transverter as described on John G4BAO's site - don't forget, it is much easier now as we can use the ADF 4351 as the Local Oscillator on any frequency you desire.

Link to G4BAO site

The ADP 200 Amplifiers


Information on the ADP 200 amplifiers, which can generate up to 32 W at 3.4 GHz after modification, is here: ADP 200 Info