2 Transverters, 1 Transverter Port

Mike-VA3MW

One of the nice things with the XVTR ports is they cover from 30Khz to 54Mhz continuously at have up to 10dbm RF output.

Thanks to this, you can run multiple transverters on 1 transverter port with the use of a common diplexor. You will have to order 1 transverter with an IF (Intermediate Frequency) of 50Mhz. You may want to get a 2M Transverter at 50Mhz. That allows you to use an IF of 50-54Mhz to cover the entire 2M band of 144-148Mhz.

http://www.q5signal.com/ is one company that can customize your transverter.

The diplexor has 45db port isolation and 0.2 db insertion loss which is pretty good.

In this example, I have 2 transverters on a common port with 1 transverter a 28Mhz IF and another one at 50Mhz IF giving you 4Mhz bandwidth on the 50Mhz IF.

This is what it looks like and it should give you some ideas of how you can expand your FlexRadio solution.

I took the CF-360 that I had and you can see the insertion loss is tolerable.

KD0RC

Thanks for sharing this Mike. I have heard about using a diplexer, but it never made sense. Now that I can see the connections, it is perfectly logical!

Demetri SVØDR

Thanks for this Mike, very helpful!

So what would be the bandwidth at 1.2ghz if I use 50 Mhz IF? Will it cover 1240-1300?

Mike-VA3MW

@Demetri SVØDR

1.2Ghz is a challenge, the good thing is that we don't need to see the entire band which is 60Mhz wide. So, the answer is no. You will have to discuss it with the company you buy the transverter from.

Demetri SVØDR

here is the reply from Corey at Q5 Signal regarding 1.2ghz:

Our 23cm Transverter covers 1284 to 1300MHz. An IF of 50 to 54MHz would cover 1296 to 1300MHz.

Mike-VA3MW

If you want to cover from 1284-1300Mhz, then you need 12 Mhz of Bandwidth.

If you use a 28Mhz IF, then that would be from 28-40Mhz IF bandwidth.

If you were to use something like a CF-360, I would move the IF down to about 20 Mhz so that the upper range would be at 32Mhz and you will still have limited attenuation on the low pass side.

This is the advantage of using a Flex radio for your IF radio since you have so much range on the transverter output. On traditional radios, your maximum TX Bandwidth is usually 2Mhz and that is at 10M (28Mhz-30Mhz). Or, you could get 4Mhz at 6M (50Mhz to 54Mhz).

Demetri SVØDR

got it Mike, thanks for the help, 73!

kd2cq

Does this design allow for full duplex (satellite) operation via a single XVTR port?

Mike-VA3MW

@kd2cq

I did a lot of digging into this and there was a thought that you can. And, while you can, it is complicated.

If you Transmit on ANT1 or 2, and Receive on RX A or XVT A, you can. However, you cannot use RX A and XVTA at the same time in Full Duplex (FDX).

You can see this in the block diagram. This is from the hardware reference manual. It shows that RX A and XVTA can be used but not at the same time.

Unfortunately, you can't use ANT1/2 to transmit on a transverter frequency.

73

kd2cq

@Mike-VA3MW Just so I understand, I could do satellite full-duplex if I xmit through ANT1/2 and receive through the XVTR port, but ANT1/2 are limited to in-band transmit? And in that case, could I transmit and receive on 10M at the same time using two 10M transverters? Any reason I wouldn't want to do that - other than the risk of frying the input to the xvtr?

Mike-VA3MW

I think you have that correct.

Also, you will have to use 10M frequencies readout, not the actual VHF frequency. This will actually might an issue if your satellite tracking software does not support transverters. You'll have to test that.

I would recommend you test it by putting your TX Panadapter on 10M ANT1 and your RX panadapter on 10M XVTA. Turn on FDX and while listening to do some 10M signals and hit MOX. See if the 10M RXA signal disappears. You can safely do this.