My Lime seems completely deaf

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?

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

Paul @N2EME , would love to get a 2x9 144mHz array up here. Sadly, I just about live aboard a sailboat (3-4 days a week), preparing her for a solo-circumnavigation next year starting June. Even a single-9 is out of the question for me. Those are the ‘space constraints’ I mentioned earlier :slight_smile: See me at https://www.marinetraffic.com/en/ais/details/ships/shipid:4821640/mmsi:367720670

I do however hope to give a whole lot of hams great IOTA opportunities in the near future :grin:

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This is definitely the best “spend” for an SDR right now for newbie or pro.

The fact that limesdr on crowdsupply is almost at $950,000 speaks for itself.

Agreed. I’m keeping mine (and not demanding a refund) only because of the potential. I just don’t appreciate being dragged in by ‘not so accurate’ advertising. Let’s face it … the 100kHz thing is a bit of a myth.

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It is nice to hear that your board is OK.
Regarding 100kHz to 3,8 GHz wide-band means lot of compromises,
Let’s see what LNA4HF can do for lower HF on LimeSDR…

73
Djani

PS I am monitoring AIS 7/24/365 from my island location :smiley:

Hi Djani,

Yes, I knew from the start there would have to be compromises. Sadly, they all seem to be in the very freq ranges that interest me the most (HF/VHF)

No worries. I’m trying the upconverter approach to get better HF, and have ordered 2 of the LNA4HF units to play with as well. Let’s compare notes and findings here when we get them.

And hopefully in the not-too-distant future, mine will be one of the boats you’ll be hearing on AIS as I sail past your island paradise :slight_smile:

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I bought a HackRF One and a HackRF Blue when they came out. The LimeSDR was my third SDR USB device. I did not buy it for the HF capabilities.

Larry in El Paso

Lucky you. You would have been a bit disappointed :slight_smile:

Perhaps you can show us those specs they claimed.
A link to where they are would really help your claim.

Sorry to bump in, but is this what you are asking for @M0GLO?

After performing the “easy fix 1” mod I wanted to perform a little comparison. The mod made quite a bit of difference by increasing signal around 15-20db, but still signal reception appears to be weaker than other SDRs. Here is an example between my LimeSDR and HackRF. Notice all of the noise/spurs/etc on the LimeSDR. Does anyone else seem to have a lot of noise? Is it a lack of filtering or did removing the inducter cause an effect on filtering?

I think that the LNA gain should be set as low as possible, looking for a slight rise in noise, then reduce …

Also the PGA gain set to a point that the signals no longer increase in db over the noise floor …ie, raise the PGA until the noise floor starts to rise too …

TIA set to max … like you already have

Yes, start from minimum (-30/-12/-12) settings for all 3.
Example settings: LNA Minus 15 TIA Max PGA 0, Pileup on 40m CW G5RV abt 60’ up.

If that is all there is and if it is the list of specs everyone is whinging about then yes that is what I was looking for even though it is nothing new.
Nothing there says anything about 100kHz perf, 100MHz perf or any other perf numbers for that matter.
And the data sheet stops at 800MHz so where everyone got the idea that this was a great performer when tuned to the bottom 1% of it’s tuning range (100kHz - 30MHz) is a complete mystery.
Wishful thinking seems to have prevailed over prior technical knowledge and rational thought.

So basically no one can show me where they were misled by Lime, just a lot of examples of how they misled themselves.
Good, then let’s stop with the whinging and the grousing and get on with making the code and matching network corrections, Lime didn’t mis-sell to you, if you are unhappy it is because you mis-sold yourself.
Own it and deal with it and move on.

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Disappointed - yes. Completely mislead - depends on the person I suppose. Myself, I just wish it was better. Personally, Based on the description I wanted to use the LimeSDR for HF bands, but everyone has seen it is not optimized for MF/HF and It’s a shame really, Not to say it’s unusable. It is be marginally useful in the 80m-6m range…b-ut not great. Anyone know howt TX looks on HF. Is it also crippled by mismatched network?

Honestly, I wont return the LimeSDR, but I was hoping for better performance than the HackRF or rtl-sdr dongle which is not the case right now.

Do you have a similar band pass network on the front end of your LimeSDR?
I ask because if not then part of that high noise floor and deafness is because the HackRF device has band pass filtering on the front end and the LimeSDR does not.
Noise floor on SDR devices like these gets seriously messed with by big signals and aggregated noise in the passband of the devices front end, in this case a full 65MHz of noise in one of the noisiest parts of the spectrum.
Get a band pass filter on it and then make your tests for a more accurate result.
I would love to see what you get, for better or worse, in a proper test like that.

When mine arrives I will be performing a similar test between my HPSDR and this devices using the band pas filters and other outboard gear that I already have in use with my HPSDR kit. I’ll post the results whatever they are so we can have a more accurate idea of perf differences between this and a system that performs as well as the Herme’s/Anand systems.