My Lime seems completely deaf

Dave,
can you please do me a small favor.
Put your Lime somewhere within FM broadcasting band with at last 15 MHz bandwith
than select RX1 L or RX1 W inputs but, leave that input open.
Use small tip with un-shielded cable from your measuring sets (AVO meter or similar)
With magnifier glass try to contact only center tip of selected RX input.
Let us know if any change noticed in signal level over all bandwith, screen copy can be
nice too…

73
Djani

Hi Djani @9a4db,

Good test. I’m guessing this is what you mean, right? ~50cm unshielded wire connected on RX_L.

1st screenshot - no ant
2nd screenshot - wire ant

73s

Hi Dave,
I think Djani’s point was connecting antenna directly to U.Fl connectors on the board. Today is ETA for LimeSDR, will clip off coils and do A/B tests.
73,
Yuri N3QQ

@nsiradio, @9a4db Hi guys. Got it. Tried that too, and not much difference. Only the noise spikes have moved in the spectrum a little.

1st - no ant
2nd - wire ant

By the way, looking closely, I see my board is missing a few components (just below T4 and T9). See 3rd. Can someone confirm those are supposed to be no-pop?

73s

Ok, thank you… at last we know now that you have some input… so problem
is somewhere in chips either hardware or software setup.

Your board is ok, that places must be empty.

73
Djani

No, THANK YOU !!!

At least we also have confirmed the uFL to SMA pigtail is OK :slight_smile:

BTW Just please compare with my Lime ->

50 ohm terminated input RX1 W (modified) pigtail is uFL to N female, Al box RF sealed

1/4 lambda vertical input RX1 W (modified)

Djani @9a4db, wow … that’s quite a difference. Your waterfall is good and clean with no ant, then well-defined and strong FM stns with the 1/4 wave.

As you see, mine above are nowhere near as good. My ‘no ant’ (screenshot 1 - both cases above) is scattered with noise right up to -70dBm in some cases.

Now, I can’t compare apples-to-apples with your setup because:

  • I don’t have a 50 Ohm terminator with SMA connector that I can try.
  • My Lime is not in Al box, not RF shielded.
  • You have N-type connectors, I have SMA

But I certainly don’t get strong signals like you do in second screenshot above.

Yuri @nsiradio has kindly offered to loan me his Lime tonight. So I’ll be able to compare his brand-new one to mine. Let’s see what that uncovers.

73s

Got mine today. Took coils from RX1_L and RX1_W off before mailman left.
Had trouble with drivers on 32 bit PC W10. Used 64 bit laptop W10, connected LimeSDR, installed driver first, verified no yellow triangle, then installed Console V3. 1/4 wave vertical for 2m on a kitchen table, FM band is operational.
After Dave will take it for a spin tomorrow will do A/B comparison with other SDRs later on HF.
73,
Yuri N3QQ
PS: I would move 4.1.1 section of Wiki USB windows drivers to where it belongs, section 2.2 BIG letters Step 1 Step 2 Step 3
Almost missed it.

Aarrgghh. Hate you all for having such fine signals :cry:

Hi Andrew, FM broadcast stations on 21MHz. BPF for 40m in line with antenna. Coils clipped off. Both check-marks for low-pass filters (analog/digital) checked. USB2.
Thanks Yuri

Hi @W7BOT,

Do you have a possibility to connect TX RF output to RX RF input using a cable? I could prepare a settings file for loopback test for you.

Hi Zack @Zack, yes, I have ordered a SMA-to-SMA loopback cable. Also proper Alum enclosure. Arrives Thursday. Thanks for settings file when you’re ready.

Today at noon, I’m visiting Yuri @nsiradio to test my Lime there against his. We’ll report results here later today.

73s

@W7BOT Hi Dave,

Couple of thoughts…

I wonder why you have not removes the chokes from RX1-L or RX1-W? Sorry if I missed this on the previous thread,

My second thought is may be put your lime in the box and mail it to one of the guys in the USA that have already got theirs up and working so that they can just slip it into their set up and tell you the board is good or not. I figure the $7 each way postage to one of them will pay for itself as it will give you a definitive answer as to whether your board is bad or not. Just a thought.

As I have commented on a few times my own Lime seems to be about as good as a TS2K on VHF RX. Not good but certainly usable. Until a suitable SSB (Digi) TX software becomes available I have been using the Lime as a Poorman’s Flex on 2m. IC746pro TX LimeSDR RX. It is very usable and my gut feeling is that it beats my USA made TVTRs on RX but does not compete with my DL made TVTR or the FCD+ but again they both would be hard to beat.

Just my thoughts…

Paul

you posted whilst I was typing :slight_smile:

Hey Paul @N2EME,

Yeah, I figured you must have just missed my post. As to why I haven’t made the mod … didn’t want to void the warranty. I have a feeling this Lime is going back for a swap-out.

Tell me more about “DL made TVTR” ???

@W7BOT

Hi Dave,

Let me first clarify that when I say “My best…” I am only looking for weak signals on 2m via moon or Digi tropo. I am not looking to chat on FM with 15 other stations within 30 feet of me on 2m. That is to say that my noise on 2m is not made by local Hams.

My tests are not Lab tests. Please see my pics on

My main way of testing is to find a weak CW beacon or set up a JT65 beacon and add attenuation until the signal disappears from a common waterfall. My view is that if I cannot see it then I cannot work it. OK that may not be 100% true with JT65 but you get the point. I have done this test on several of my 2m RX including my USA made TVTRs, a few Icoms, a TS2K and my baseline RX of a FCD+. Long story short the DL TVTR comes out “Best” in my world by far apart from when compared with the FCD+. It is, in my world, better than the FCD+ but the jump is no where near as big as when comparing it to the others.

This is the DL TVTR I use. I think at last exchange rate that I looked at they were $357 shipped?

http://shop.kuhne-electronic.de/kuhne/en/shop/converter-transverte/transverter/MKU+144+G2++Transverter+module/?card=19

Paul

Paul, VERY cool little piece of kit. A bit pricy, but probably worth every cent from what you say.

I’m also into weak-signal and LEO bird comms. Almost exclusively Digital Modes. Hardly ever voice and certainly never 2M repeaters :slight_smile:. I’d love to try some EME but simply cannot get a decent 4x yagi stack up here within my space constraints.

Take care, and thanks again.

73s

@W7BOT 2x9 is more than enough to work lots of stations on EME and makes for a small footprint. With the clubs 4x7 set up I have worked a single 9 station. The N4EME 4x7 is nice as it is a very small footprint for roving with as well as loaning out to other hams to try EME with. If you look in the N4EME EME Rovers web page you can see it in the background.

@andrewback Andy and @Zack Zack,

Just a quick feedback after my 1-to-1 testing with the Lime of @nsiradio Yuri.

Yuri, firstly HUGE thanks for your time today. Thank-you Sir!

Andy and Zack … good news is my Lime performs like his, so it looks like it’s working as designed and won’t need to be replaced … BUT ‘working as designed’ is nowhere near where it needs to be performance-wise based on the specs you published on Crowd Supply.

After Yuri helped me remove the coil below T3 (i.e. we effected easy-fix 1 on RX1_L), the FM performance that I was using as a baseline (see ton of posts above) was suddenly 20dDm better.

So … 1st lesson. Change your messaging around the easy-fix 1. It’s NOT ONLY FOR HF … the Lime is DEAF even up to 100mHz and above… until you remove the coil. I was hesitating to do the mod, not wanting to invalidate your warranty, but glad I did. It made a HUGE difference. I realize I can now no longer return this board.

Still, Lime RX performance is substantially below other comparative receivers, as you’ll see from my posts above. I’m still performing further testing, but wanted to post this to inform Zach not to waste time building a test.ini script for me that loopsback TX to RX as discussed above.

Fuller report will reach you in a day or two … for the benefit of other newbies that believed this SDR would be the best spend of their $$$ based on your advertising on Crowd Supply.

73s de Dave W7BOT