[Hackrf-dev] Is my new (old) HackRF Deaf?

Jerry jsternmd at att.net
Fri Jul 14 12:59:21 EDT 2017


I bought another HackRF from NooElec one and using the same laptop with Windows GNU 3.7.11 --- not changing any of the gains or settings (basically swapped the old HackRF with the new) --- the new one shows plenty of local FM signals across the FM commercial band while putting back the old HackRF the spectrum display was silent except for the DC offset.  

Jerry NY2KW

-----Original Message-----
From: HackRF-dev [mailto:hackrf-dev-bounces at greatscottgadgets.com] On Behalf Of Cinaed Simson
Sent: Tuesday, July 11, 2017 4:53 PM
To: hackrf-dev at greatscottgadgets.com
Subject: Re: [Hackrf-dev] Is my new (old) HackRF Deaf?

On 07/10/2017 09:36 PM, Jerry wrote:
> Jake
> 
>  
> 
> Thanks for the sound advice.  I have had spectrum analyzers and 
> learned early to be careful with nearby RF sources ☹
> 
>  
> 
> Right now I am getting a wide confluence of signals between 98.5 and
> 101.5 on the FFT.  If it were my SA I would narrow the bandwidth to 
> improve the signal resolution but on the Osmocom Source changing Ch0 
> Bandwidth from 10 Hz to 500 Hz doesn’t appear to change the FFT 
> display noticeably.
> 
>  
> 
> Attached is a picture.

The largest signal is the HackRF's DC offset.

The tutorials will show you how to avoid it.

-- Cinaed
> 
>  
> 
> Jerry NY2KW
> 
>  
> 
>  
> 
> *From:* HackRF-dev [mailto:hackrf-dev-bounces at greatscottgadgets.com] 
> *On Behalf Of *Gavin Jacobs
> *Sent:* Monday, July 10, 2017 6:22 PM
> *To:* hackrf-dev at greatscottgadgets.com
> *Subject:* Re: [Hackrf-dev] Is my new (old) HackRF Deaf?
> 
>  
> 
> Jerry,
> 
> Learning how to use Ubuntu, and Gnu, and HackRF is a challenge! I went 
> down that path about a year ago. The issue you describe hits every new 
> user. When you are running GNU radio, you have to turn up the IF gain 
> to about 40 - it defaults to 0. Also, turn up the BaseBand gain to 
> about 30. Leave the RF gain at 0 (that setting is confusing; a value 
> of 0 just means the RF LNA is left off; 14 means it is on; but you 
> rarely need it on).
> 
>  
> 
> Also, a word of caution. Since you are a ham, you likely have an HT or 
> a base station. You have to take care to never exceed the maximum 
> field strength anywhere near the HackRF. I don't recall the exact 
> spec, but basically if you transmit with a 5 Watt HT, right next to 
> HackRF, you can fry the RF front end.
> 
>  
> 
> Hope that helps.
> 
> Jake
> 
>  
> 
> ----------------------------------------------------------------------
> --
> 
> *From:*HackRF-dev <hackrf-dev-bounces at greatscottgadgets.com
> <mailto:hackrf-dev-bounces at greatscottgadgets.com>> on behalf of Jerry 
> Stern <jsternmd at att.net <mailto:jsternmd at att.net>>
> *Sent:* July 10, 2017 2:54:16 PM
> *To:* hackrf-dev at greatscottgadgets.com 
> <mailto:hackrf-dev at greatscottgadgets.com>
> *Subject:* [Hackrf-dev] Is my new (old) HackRF Deaf?
> 
>  
> 
> Is my HackRF deaf?  I am a ham radio hobbyist and I bought a HackRF 
> One to enhance my deeper learning of SDR but also as a broadband RF source.
> To my dismay, installing the software has become days of learning 
> Ubuntu basics and dealing with instructions that are at times outdated 
> or nuanced towards a person with much more than basic Linux skills.  
> So, I gave up on Ubuntu only because it was faster for me to install and test
> with Windows 7.   My HackRF One (GreatScott) must have been a leftover
> as the firmware was dated 2014(August).  I installed the latest 
> version HackRF tools and updated the firmware to Feb 2017.  I followed 
> Mike's video tutorial for creating a basic GNU flow for FM and also 
> installed SDR#.  I have very strong FM broadcast stations in my area 
> which I can easily demodulate with my Rigol Spectrum analyzer using the ANT500.
> However both with GNU and SDR# my HackRF appears deaf in FM broadcast 
> mode.  I read that a few years back there may have been some issues 
> with cold solder joints on the HackRF pcb....  I have a lot of test 
> equipment
> - from RF generators up to 2 GHz, etc but before I go that route is 
> there something I am perhaps missing in my setup.  Not sure where or 
> what details to provide here without overloading my question further .
> 
> 
> 
> Thanks
> 
> 
> 
> Jerry
> 
>  
> 
> 
> Sent from my iPhone
> 
> 
> 
> _______________________________________________
> HackRF-dev mailing list
> HackRF-dev at greatscottgadgets.com
> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
> 

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