On Fri, 25 Apr 2014 08:42:16 -0700 Chris Albertson <albertson.ch...@gmail.com> wrote:
> You best bet is to change out the antenna. You can buy them with a higher > built-in gain up to about 40dB. Buying a better antenna is also on the list. But i would still like to have an LNA, even if it's just to see that it doesn't help :-) > My understanding is that designing a GOOD > LNA is not so easy as little things like the exact layout of the PCB and > how the PCB transitions to connectors matters a lot. Well, the idea is to use one of the monolitic types like the TQP3M9036 [1] which basicall only need power on the output. These should work quite well without a PCB. Though i'm really thinking about getting a small PCB run, both for my bias tee and the LNA, but that will incure a minimum cost of around 100EUR (same price whether i buy 1 or 10, though) > But you can buy these > ready made for cheap. I've seen complete LNAs in an enclosure with > connectors at good prices on eBay. The user manuals I have say using 75R > cables with compression type F connects is OK. I doubt the cheaper type > f-connectors would work well. I looked at the ones available on ebay, but they were either made for sat solutions and require 12V, which would complicate the whole power supply system. Or are >100USD. Given that i can get a cheap LNA chip for 1USD or an expensive one like the TQP3M9036 for 4, then i can build one myself for less than 20USD that should do the job just as well. > I have a good high quality Tremble in-line amplifier with N-connector and > the ability to pass DC. In my experiment I place the antenna indoor and > use amplifier and then outdoors with no amplifier. I get MUCH better > results with my 26dB gain antenna on the roof and 25 feet of cable than > with indoor amplified antenna with short cable. My un-scientific > conclusion was that amplified noise is still noise. Well, GPS signal is mostly noise anyways ;-) The idea would be to place the LNA close to the antenna, in order to need less amplification in the bladeRF. And also to compensate for the longer cable i plan to use (getting the antenna to a better location) Attila Kinali [1] http://www.triquint.com/products/d/DOC-B-00000120 -- The trouble with you, Shev, is you don't say anything until you've saved up a whole truckload of damned heavy brick arguments and then you dump them all out and never look at the bleeding body mangled beneath the heap -- Tirin, The Dispossessed, U. Le Guin _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.