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 > <[email protected] <mailto:[email protected]>>: > >> 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. >> _______________________________________________ >> HackRF-dev mailing list >> [email protected] <mailto:[email protected]> >> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev > > > _______________________________________________ > HackRF-dev mailing list > [email protected] > https://pairlist9.pair.net/mailman/listinfo/hackrf-dev > _______________________________________________ HackRF-dev mailing list [email protected] https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
