Limesdr Mini TX under 30mhz?


#1

Hi guys,
I want to transmit in the HF Ham bands. My mini is Tx-ing fine with Sdr console and SdrAngel, but only down to 30mhz.
Any ideas how should i unlock the tx under 30mhz?

Best Regards,
Kiril


#2

@kiromn - Kiril,

Not sure about SDRConsole because I’m not a user of that app, but you can easily transmit below 30 MHz with SDRAngel when you activate (press or select on the GUI) the ‘NCO’ button on the form. The NCO button does a subtraction from 30 MHz and if I recall right, there is also a tuning step you have to adjust (from 30 MHz) to get the Lime (original or Mini) to transmit and receive in the 2 - 30 MHz region in SDRAngel. Here is an excerpt from the author, Edouard (F4EXB) on that issue:

"…Hi Marty,

in fact the formula is Fc = Flo + Fnco where Fc is the frequency of reception, Flo the LO frequency and Fnco the NCO frequency. So let’s say you want the LO to be 30 MHz and frequency of reception of 7 MHz then you have to set the NCO to -23 MHz. Remember to adjust the low pass filter (which is centered on LO) so that the center frequency is in the band,

Best regards,
Edouard…"

Hope this helps, please keep us advised on your progress.

73 de Marty, KN0CK


#3

This is link for Mini board, 20m band ini settings for LimeSuite-GUI.


Just use LimeSuite-GUI, connect Mini board and open fsettings file. Now you should have carrier on 14.8MHz (30MHz(SXT page) - 15.2Mhz(NCO) downconverter mode).
It is possible to receive with FFT viewer and even TX in loopback mode but I’m missing some setings for TX part.


#4

I am receiving fine on the whole HF band without any additional settings in SDR Console. I had just to attach FM Broadcast band stop filter and now i am receiving FT8 signals on 7 and 14 mhz. However for transmitting it just does not work even with NCO setting. It transmits till 28-29mhz and then just stops.
It will be great if this can be fixed for QRPP digital modes and CW.
I will try the ini file after the end of the SSTV event from the International space station. They will transmit pictures till tomorrow on 145.800. You can decode them with MMSSTV software :slight_smile:


#5

Ok, I have managed to transmit on 14mhz with NCO and the setting file from yt7pwr.
However i got some cracking of the transmitted audio when rooting audio from wsjt-x to sdrangel with virtual cable


#6

Possibly next week I will work on the HF transmit, apparently for HF I must change some oscillator values. A user has done this and claims it works!

Currently attacking the Full Duplex operation for Es’hail 2.


#7

Will you please share your setup for working Es’hail 2?
Do you use Limesdr or something else?
Best Regards,
Kiril LZ1CLA


#8

Well,

I can’t do the Mini work at the moment as, sadly it broke after being handled too much. My fault I know, but I’ll have to buy another for the development.

We’re currently testing the code to iron out some bugs related to the Mini - on the Es’hail 2 the Lime USB and Lime Mini are both working on SSB with my software, but as always it’s early days. I think maybe 4 weeks needed before I can lay it to rest.

I’ll order another Mini tomorrow. Bugger!


#9

What kind of LNB do you use for receive and transmit?
Do you use additional PA on transmit ?
73 de Lz1CLA


#10

Hi,

Octagon (I don’t have the model here), i don’t have a PA yet but it will be a 10W PA. ~2dB loss between the PA and the 1.4m prime focus dish (10m Ecoflex 15 Plus cable), so ~ 6W at the feed. Signal will be very good.