Need 630m Transverter IF above RF band

Dick Illman

SmartSDR V2.0 restricts the IF of a transverter to only below the operating band.This makes a 630m transverter such as the MF Solutions Transverter not possible. How about a check box for IF above or below RF band.

Tim - W4TME

The transmit frequency is not restricted when using the XVTR port.

Mike va3mw

Correct.  The specs to the xvtr port are in the manual including the RF power level.  A very nice feature on the 6000 series.  

You just  need an amp now.

Dick Illman

Work around was to ignore any transverter settings and simply tx on 10.472 IF through xvtr output and listen direct on RX A.  Since I am using GPS 10MHz output at the LO I have visual tx/rx sync. I just align slice A and B on the screen for visual reference.

Ria

You do not need a transverter for 630m. You only need a low drive amplifier. 

Chuck

Class D amps usually require a drive frequency of twice the output frequency, i.e. drive of 950kHz for an output of 475kHz.  So, it would be very helpful have an IF frequency ABOVE the RF frequency.  It appears SSDR does not support this.  This quite inexpensive 300W amplifier is an example: http://www.g0mrf.com/630m.htm

Mike va3mw

That is interesting.  Why can you not use the XVTR port at 950khz?

The XVTR port allows continuous coverage low power (+10 dBm max) transverter IF from 100 KHz.  (page 96 of the manual)

Page 99:

Max Power (dBm): Enter the IF input power level to the transverter to achieve maximum output power of the transverter.  This will limit the output power that SmartSDR allows to be provided to the transverter.  This value may be up to +15dBm for IF frequencies below 80MHz and up to +8dBm for IF frequencies above 135MHz (default: 0dBm).  The value set in this field, should match the power output when the RF Power slider is set to 100.  The lower end (values near 1 on the RF Power slider) will be approximately 20dB lower than the Max Power setting. 

Andrew VK5CV

A TC4428 can be driven directly. That's what I am building for 2200m.
http://cdn-ak.f.st-hatena.com/images/fotolife/W/WideR/20120822/20120822003844.jpg
http://ww1.microchip.com/downloads/en/DeviceDoc/20001422G.pdf
Andrew VK5CV

Chuck

Regarding SSDR transverter capability, page 99 of the SSDR manual states "Currently SmartSDR only understands high-side injection so the IF frequency must be below the LO frequency of your transverter."  This restriction precludes using a SSDR transverter setting for a 630M amplifier that has a higher frequency IF drive requirement (e.g. 0.950+/-MHz) such as the G0MRF 630M amplifier described here:
http://www.g0mrf.com/630m.htm
Providing transverter "low-side injection" would greatly simplify the use of this class of amplifiers on the 630M band.
Chuck, AE4CW

Tim - W4TME

it is possible that changes in the software done after the doc was written will allow for low-side injection.  If not, this is something we may consider adding in a future version of SmartSDR, but it would not be a high priority program change since a 630m amp can be directly driven from the radio as noted above and not have the inherent issues with using an amp that requires frequency doubling of the RF input. 

Dick Illman

However if you want to have a single receiver slice with an iPad for example, you need to have a transverse in speak of just an amplifier.

Tim - W4TME

No, you do not.  Just tune the slice to 630m and set the TX antenna port as the XVTR port.  Then connect a low drive PA to the XVTR port.  For RX you can use the same port (XVTR)

Dick Illman

How do you get receive signal back to the XVTT receive input? An external relay?

Tim - W4TME

On the slice, select XVTR as the RX antenna port.

Dick Illman

I may be missing something but if the single XVTR output is connected to the input of the amplifier, how is the antenna also connected to the single XVTR port?

Doug Hall

I think it's assumed that the amplifier has built-in T/R switching.

Tim - W4TME

Doug is correct.  It is the same as connecting an amplifier to the ANT-1 or ANT-2 connector and the antenna is connected to the amp.  The RX and TX antenna selections in the slice are the same, XVTR rather than ANT-1 or ANT-2.