GPS + WiFi

GPS is at 1.6GHz. Which WiFi frequency plan are you looking at? Just as long as you don't have LO spurs falling in a receive band you should be OK.

Beware: I've been a party to both single- and dual-conversion GPS units, and a dual-conversion WiFi _repeater_ at ~5GHz.

...Jim Thompson

I see 1.2276 GHz listed as a civilian GPS frequency as well as

Sounds like fun.

Best regards, Spehro Pefhany

Been there, done that with both Wi-Fi and 900-mHz spread spectrum radios at 1-W levels. No apparent loss of GPS lock. We do try to keep the telemetry and WI-Fi antennas on the bottom of the case, and the GPS on the top--which helps as the unit is flying, and the GPS Satellites are up and the ground stations are down! ;-)

I did see some problems when the GPS antenna was too close to the slot for insertion and removal of the logger CF card. I think it was the processor emi, and not the radios, that was causing the interference.

Simple test procedure: Wave your handheld GPS around the system and watch the 'satellite bars'. They really do shrink when when the preamp starts to saturate. (I guess). $100 is pretty cheap for a handheld, 2Ghz, near-field, EMI test unit with graphical display (and a few other useful functions)! ;-)

Hey----they can keep the signals sorted out in units as small as cell phones. I guess that says something good about the folks who design the front end and signal processing of GPS receivers.

My next challenge is a data buoy where GPS, 900Mhz telemetry, and possibly an OrbComm satellite modem have to coexist on on an oceanographic buoy. Not much chance of great antenna separation there, as none of the radios work too well under seawater ;-) OTOH, one of the engineers at the local university showed me a neat antenna with a GPS patch molded onto the top of a quarter-wave whip (for what frequency, I cannot recall). If the frequencies are different enough, I guess you can get away with quite a lot.

Mark Borgerson

Hello Spehro,

As long as you have a solid ground structure, shielding and good filtering I don't think it should be a problem. Haven't done it myself up there yet but have done it around 10MHz. That was a bit tougher where the receiver had to hear the grass grow while the transmitter was blasting more than 100W.

Regards, Joerg

Wow, that's amazing, I just started researching the same thing! Do you happen to know some nice low-power OEM WiFi modems? I just discovered DPAC

Thanks,

--DF

Lantronix has one as well. Dunno about the power level, it's not a big concern for me, I have a rather robust portable source at hand for this application.

Best regards, Spehro Pefhany

I didn't elaborate enough on that.

Do you have access to a spectrum analyser?

I'd "sniff" both units to see what their frequency plans are. The frequency plans for many of these single-chip systems can be "unusual" ;-)

...Jim Thompson

Go for the DPAC system! If you talk to support, tell Joe I sent you... 8-)

(and, I own stock!)

Charlie

how much are they? I cant find them in

I just got a quote: $110 for the WLNB-AN-DP101 in small quantities. Evaluation kit is $500.

--DF

reward"

DPAC

others.

Better get rid of it then. They want me to sign an NDA before giving any information. Silly policies will not gain them many customers. Lantronix WiPort looks good too!

--DF

No, maybe I should ask Win what he wants for his old "inferior" unit if/when the funding comes through.

Okay.

Best regards, Spehro Pefhany

How far are you from the White House?

About 9 hours drive, or an hour by commercial jet/cruise missile, why do you ask?

Best regards, Spehro Pefhany