[Hackrf-dev] LNA4ALL

[Cinaed Simson]

For transmitting multiple signals at once on a single HackRF I use an
external LNA and band pass filter or low pass filter.

But I always put a variable attenuator in the line until I confirm the
strength of the signal since I'm worried about the reflected power at
the antenna.

I can estimate the reflection coefficient at the antenna but I don't
know the total power coming out of the HackRF + LNA.

Otherwise I don't use a LNA for transmitting.

For receiving I don't need a LNA - I use low pass or band pass filter.

I haven't played with GPS yet.

I got rid of my telescopic antenna and picked up two wide band PCB log
periodic antennas. I already had a couple of copper HF/VHF antennas.

However, it did cost more than LNA.

-- Cinaed



On 02/01/2017 03:48 AM, Ulf Bertilsson wrote:
> blew my rf amp on my board, so I used that to compansate.
> 
> As with all lna it increase noice, substainable to overload etc.
> 
> I found hackrf very weak even when rf amp was ok.
> 
> Also used it on the tx path for gps jam/forge etc.
> 
> Sendt fra min iPhone
> 
> Den 1. feb. 2017 kl. 11.50 skrev Marc Pàmies Massip
> <mpamies247 at gmail.com <mailto:mpamies247 at gmail.com>>:
> 
>> Dear all,
>>
>> I wanted to ask if it is worth using an external LNA (specifically an
>> LNA4ALL) to improve the reception performance of the HackRF-One. I
>> know it is a basic part of any radio communications systems, but I
>> don't get why it could be necessary if the HackRF already incorporates
>> an internal LNA. Does the use of an extra LNA has any drawback that I
>> might consider? It would improve the reception of weak signals?
>>
>> Wouldn't it make more sense to add a preselector filter instead, as
>> those are missing in this device? 
>>
>> Thanks in advance,
>>
>> Marc.
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> 
> 
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