In the UK we have a frequency allocation from 70.0 to 70.5 MHz. This band (or parts of it) is increasingly being allocated in europe and africa. CEPT now a footnote:"EU9: CEPT administrations may authorise all or parts of the band 69.9-70.5 MHz to the amateur service on a secondary basis."

Is it possible for the SunSDR2 Pro to transmit in this band, even with reduced performance?

Steve, G4AUC

Venturer wrote: Yes, it is possible to use SunSDR2 Pro in 70 MHz band, but Power Amplifier not working on this band. User can use low power DAC output(10 mW) and direct input RX IN. Must be used external own PA in TX mode and BPF filter in TX mode.
We will add 4M button to new version of the software.

Hi, this is an old thread, but I guess still many reader.

I have done some rx test on 4m (SUNSDR2 Pro, indication general band) using the same setup as with my 7300 (5 El Yagi, 15dB LNA with 1 MHz wide band filter , 3dB Splitter).
Reception of usual (P14) 4m beacons is slightly better over 6hrs monitoring. I used the normal HF antenna input on SUN2PRO.
:
I my location SunSDR produces less subsampling qrm than my IC7300 - apparently a far superior lowpass filter in Sun2Pro.

How to activate TX mode - PTT (DAC Out: 10mW).
I use ESDR2, ver 1.1.3, so not sure if PTT is already implemented in new beta software.

With the high stability and excellent frequency resolution (1Hz or less) of the SunSDR , it certainly would be interesting to unlock the DAC over its full range.

73 Charly, DF5VAE

When I select 70MHz the MOX and Tune buttons are greyed out inhibiting selecting output from DAC port.
Am I missing something in setup?
Have SAWTEK 854666 filters to try in ADC/DAC PORTS, On ADC works real well kills very local VHF FM station.

Yes, it is possible to use SunSDR2 Pro in 70 MHz band, but Power Amplifier not working on this band. User can use low power DAC output(10 mW) and direct input RX IN. Must be used external own PA in TX mode and BPF filter in TX mode.
We will add 4M button to new version of the software. ....

Hello any news for ....... 4 METERS BUTTON ... is very nice to work with sunsdr the 4 meter band thanks

Hello Vassil,
very good job -

But why do you (or EE) suggest to use ADC in for 70MHz reception -
I can speak only for my SUN SDR 2 - In this unit the 80 MHz low pass does not attenuate the 69-71 MHZ frequency band that I could notice a loss of sensitivity - so 4m reception is straight forward.

For Tx application the use of DAC output is mandatory - I have not seen any (Ham) wirdeband power amplifier covering 160m to 70MHz . so there is no other option.
PLEASE do not restrict with next software update the 4m RX to ADC in only -
Thanks,
Charly, DF5VAE

As there are many (g)estimates about RX performance of the SUN SDR pro on 70MHZ just a screenshot I took this morning on 70.280.

My Sun SDR shows no degradation of sensitivity on 70 MHz - due to proximity of 80 MHz Rx lowpass.

The clean bandscope is due to supplementary bandpass filtering removing all possible under- and oversampling products from nearby high power broadcast transmitter.
The remaining peaks are timebase related and cannot be removed by external filters.

I hope direct RX to antenna connection will be kept with future updates, only 70MHz TX needs to be routed to DAC out.

Hope to see you in a few days on 70MHz

Charly, DF5VAE