LimeSDR USB-Using L1TX & L1RX adapting for 100 Khz to 54 Mhz


I am looking to use channel 1 for HF only. I would then use T/R2 W or H for 144/220/440. I doubt I will go over 440 Mhz with this unit (Other plans for that). My LimeSDR USB has the #1 mod to the RXL1.
Is there anything I can do to improve Channel 1 for HF/6 meters? RX/TX?

Thank you,


@AA7QQ - Ed,

None - That is the mod required for good HF (100 kHz to 56 MHz) to VHF (56MHz to well over 220 MHz) reception. I would even go so far as to say it would work acceptably into the 70cm band as modified, too. I know - I had beta Limes that ran fine in those bands for receive and did exceptionally well on HF after the mod. I may have to caution you that you might want to use the older FPGA loads (one or two versions from where we are now and is very straightforward to load onto your Lime) because I’ve been hearing some varying remarks about HF performance with the latest FPGA load - does not affect 2m or 70cm.

Let me know if you need more info - Welcome to the group…!

73 de Marty, KN0CK


Excellent. I do remember that you had some special settings. Once it is all together, I’ll have to get them from you. Still learning & pounding this stuff in my poor blonde brain.

Thank you,


@AA7QQ - Ed,

Anytime - just keep me advised what you need and I can help you though it. There’s A LOT of us wanting the Lime to be a rather wonderful wideband Ham rig and the potential is certainly there for it to happen.

Keep me tuned-in - 73 de Marty, KN0CK


When you have used HF, do you have a t/r switch, or are you only using T or R in the lime? Might there be a trigger signal for that?
I am lucky enough to have a brilliant code monkey at work. He loves the lime & Udoo X86 Ultra. He actually ordered the Jetson TX2 Dev kit. I’m thinking about getting one for use with the XTRX in the future. That would be fully integrated with the amps at home.

If I had never bought that Ten Tec Pegasus…



@AA7QQ - Ed,

Well, when you play with this stuff enough that Ten Tec rig will seem rather dull compared to a radio that you built yourself and know inside and out - - and you didn’t have the outlay for it either compared to the Lime. :slight_smile:

Well, for now I’m going full duplex for the experimentation I’m doing but I plan, longer term, to go simplex and will have a T/R switch in place for the Lime. At some point Edouard @F4EXB was going to play with the GPIO for the Lime, but I don’t know if he was going to do that on the companion board (which is pretty pricey, but will DEFINITELY drive medium-sized relays) or try working that with the GPIOs on the board itself. I have heard of other Hams who have actually worked with the code to switch the bits on the GPIO on the LimeSDR to make the PTT work. You may want to wade through the threads within the past week to see what they’re doing on that. At the moment I have my nose in GPS with the Lime and will return to Earth when that’s run its course.

But, definitely, I plan to implement a T/R switching off the <really low voltage…like 3.3V> GPIO on the LimeSDR board and will build up an interface that will steer a larger relay for the antenna switching - it’s in my plan soon.

Let me know if you have any other questions on any of this, Ed - 73 de Marty, KN0CK