H-L V1.22 with 50 MHz transverter

[Heikki Ahola]

Hello Group !

I have a 50 MHz transverter of my own (?) design which needs 10 - 12 MHz injection from hf rig. I have previously used it with my SoftRock-type transceiver and found that - 4 dBm in just about right for TX (5 W out). I have studied my H-L /PowerSDR combination and noticed that a transverter setup when defined in the XVTR menu can output a fixed 200 mV peak/50 Ohms, which happens to be abt -4 dBm. On the other other hand, in HF  my H-L outputs max +14 dBm (before Norton amp and PA) fully adjustable from zero to max. Is this the case with current firmware/PowerSDR ? Do the other software available for H-L behave differently ? I do not need much power for the transverter but some adjustment would be appreciated !

73 de Heikki (OH2LZI)

[Steve Haynal]

Hi Heikki,

It sounds like you are using the older HL firmware which uses the AD9866's IAMP. This had quite a few spurious emissions. With the HL2 and HL1.22+Jim's v1.42 fontend board, we are using the lower power TxDAC output and then a OPA2677 to obtain output of a bit over 20 dBm. The TxDAC has lower and cleaner output. You might consider using that output without an OPA2677, enabled with the TxDAC firmwae, for your transverter. There is also one resistor value that you can change to further lower the output. See the AD9866 datasheet for Rset. You might also consider adding an attenuator.

73,

Steve

KF7O

[John Williams]

Heikki,

I still have a few extra 1.42 frontend boards if you prefer to take that route.

John

--
You received this message because you are subscribed to the Google Groups "Hermes-Lite" group.
To unsubscribe from this group and stop receiving emails from it, send an email to hermes-lite...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

[Heikki Ahola]

Steve and the Group,

It seems that I have not explained my problem clearly. I am using the older firmware with PowerSDR but in any HF band it works OK. The output from AD9866 is adequate for the Norton/PA (5W out) and to drive my small 20 W amp I use an attenuator before the Norton amp in order to maintain abt 80 - 100 drive. I now realize that my problem (again!) may be related more with the PowerSDR settings because when configuring a 50 MHz transverter (40 MHz XO, 10-12 MHz out from HL) I can get only -4 dBm from AD9866. I am also wondering if the other software (QUISK etc) might behave differently. I could try another approach, forget the transverter config and just drive my tranverter from 10 - 12 MHz HF, but at least PowerSDR refuses to transmit outsode the designated ham bands. So, if anyone has tried PowerSDR/HL with any transverter, I would be delighted to have that info.

73 de Heikki (OH2LZI)

[Steve Haynal]

Hi Heikki,

I'm not too familiar with the PowerSDR software. I remember once to do an out of band test, I manually edited some configuration file in a text editor to adjust the TX band limits. I suspect this should be documented somewhere and the power users of PowerSDR on the openhpsdr group or the Yahoo Apache Labs group may do a better job of answering this question.

73,

Steve

KF7O

[Heikki Ahola]

OK! I did some inquiries and found out that band limits can be disabled in the version of PowerSDR for HPSDR (currently PowerSDR_mRX_PS_v3.3.9.0) which I have been using with little problems. This means that I can get full output in any frequency in the normal operation in HF. There is, however, a setup procedure for transverters, where You specify the target frequency and the XO frequency, as a result You will have the true operation frequency in the display. This is what I did try and then, the power output drops down to -4 dBm. In Hermes hardware, a separate output exists for transverters, which, in my opinion, is controlled by the firmware not included in H-L firmware (???) This is (was ?) my problem ! I would imagine that in H-L the PowerSDR transverter procedure disables or limits the normal output port but while no ancillary port to be enabled. Knowing all this, I can carry on with my transverter setup although 50 MHz may be very silent until next summer.

73 de Heikki (OH2LZI)