Welcome to the new FlexRadio Community! Please review the new Community Rules and other important new Community information on the Message Board.
If you are having a problem, please refer to the product documentation or check the Help Center for known solutions.
Need technical support from FlexRadio? It's as simple as Creating a HelpDesk ticket.

Transverter receive artifacts

Member, Super Elmer Moderator

I have a Flex 6400 and a UT5JCW 2-meter transverter. The transverter works great, especially for such an inexpensive piece of equipment.

I do notice that across the 2-meter band, there is a 10 dB bump centered near145.600. I get this regardless of antenna (or even no antenna) and wonder if this is an artifact of the transverter (which I suspect), or if an expensive transverter like the Q5 would exhibit the same behavior. I am sure that it is not the 6400, as 28 - 32 MHz is quite flat with no antenna connected.

The picture below was captured with an RF Gain setting of 16 dB. At -8 dB, the display goes flat, but weaker signals disappear. At 0 dB, I get a 2 - 3 dB bump, and at 8 dB I get a 5 - 7 dB bump (just eyeballing the display, not a precise measurement). 16 dB gives me the sweet spot of an 8 - 10 dB drop when setting the rig to no RX antenna compared to the XVTR.

image.png

I also get receiver dropouts when strong signals stop transmitting (see circled items, above). I have to believe that this is an artifact within the transverter but want to know for sure. I get no such dropouts on any other band, regardless of signal strength.

If anyone can confirm what is causing these artifacts, I would appreciate it.

Tagged:

Welcome!

It looks like you're new here. Sign in or register to get started.

Best Answer

  • Member ✭✭
    Answer ✓
    I have a 144MHz<->28MHz transverter from transverters-store.com (RIP?) which I'm guessing is close enough to which ever version you have. I noticed the same the spectrum shape when I first hooked it up. Hooking up the transverter to my tinySA confirmed that it was the transverter's shape, not the FlexRadio. I grabbed a screenshot from my tinySA just now, and you can see a similarly shaped profile on the instrument.

    Mike's video on transverters (https://www.youtube.com/watch?v=xJ5fIe0bWDE?t=1m15s) does NOT show such a shape, and he says (at timestamp 4:57) he's using Q5 transverters. Since they're 5x the price, it's not too surprising that they perform better.

    I haven't seen dropouts like you showed. I just tried blasting my transverter by keying up my 5W HT right next to the transverter's antenna, and no dropout. Maybe that's not harsh enough?

Answers

  • Member, Super Elmer Moderator

    Thanks Reed, that helps confirm what I was thinking. I suspect that the strong sigs are very close, and fairly high power. They show up bright red on the waterfall.

  • Administrator, FlexRadio Employee, Community Manager, Super Elmer, Moderator admin

    Do you see the same signals on 28.200 Mhz? That is the actual frequency that the radio is operating on.

    73

  • Member, Super Elmer Moderator

    Hi Mike. No, 28 - 32 MHz is very flat with no antenna connected. I am pretty sure that it is the Ukrainian transverter. Is your Q5 transverter flat across its operating range?

Leave a Comment