Search found 11 matches

by rjmura
Mon Sep 07, 2020 9:30 pm
Forum: RTL-SDR Discussion
Topic: Using the dipole antenna kit - setting correct lengths
Replies: 1
Views: 291

Re: Using the dipole antenna kit - setting correct lengths

the total length of a half wave dipole should be a half wavelength. so for 437.8 MHz, the total length (both sides) is 32.7 cm, and from center to one end is 16.3 cm. the short antenna fully extended has a total length of 32 cm, which should be close enough. the attached vna plot of the short antenn...
by rjmura
Sun Sep 06, 2020 8:53 pm
Forum: RTL-SDR Discussion
Topic: Meteor M2 decoding
Replies: 1
Views: 466

Meteor M2 decoding

was able to decode Meteor M2 lrpt up until a month ago. now, its signal bandwidth has increased from about 100 kHz to 250 kHz, and the constellatiion has changed from 4 dots to more of a donut with a dot in the middle. unable to decode. am running dde client v1.2, demodulator v 2.3, and decoder v 5....
by rjmura
Mon Jul 20, 2020 10:48 pm
Forum: Antennas
Topic: best v-dipole height for noaa satellites
Replies: 0
Views: 1365

best v-dipole height for noaa satellites

If you use a tripod for your v-dipole, you may have read that it should be 1 meter above ground. in my case, 92 cm gives nearly noise free reception above 15 degrees elevation. you should try varying your antenna height by 1 or 2 cm for your location. the ground reflection changes the antenna patter...
by rjmura
Mon Aug 12, 2019 2:45 am
Forum: RTL-SDR Discussion
Topic: Newb trying to receive Weather Faxes
Replies: 4
Views: 3098

Re: Newb trying to receive Weather Faxes

what program (e.g., sdr#, sdr console, hdsdr, sdruno) are you using for your radio? for step 1, when you run your sdr radio, look for a configuration menu (like a gear) that shows "quadrature sampling". if you click on the drop-down box, you should see something like "q branch". step 2 is the noaa w...
by rjmura
Sun Aug 11, 2019 3:24 am
Forum: RTL-SDR Discussion
Topic: Newb trying to receive Weather Faxes
Replies: 4
Views: 3098

Re: Newb trying to receive Weather Faxes

i don't have a mac, but you may be able to figure out how to do it by seeing how i do it on a pc. 1. you can tune your sdr below 28 MHz by direct sampling the Q branch. on sdr sharp, this means changing the sampling mode from quadrature sampling in the configure source menu. 2. go to https://www.nws...
by rjmura
Tue Jul 30, 2019 1:27 am
Forum: RTL-SDR Discussion
Topic: Max Volume
Replies: 14
Views: 6271

Re: Max Volume

you may have inadvertently created a ground loop and induced 60 Hz power into the system. try disconnecting the ground to the shield. i need to crank up the volume all the way in sdr# for a green signal of 75% in wxtoimg. if i lower the volume in sdr#, the level in wxtoimg also drops up to the point...
by rjmura
Wed Jul 24, 2019 11:45 pm
Forum: RTL-SDR Discussion
Topic: Max Volume
Replies: 14
Views: 6271

Re: Max Volume

just reduce the volume in sdr sharp.
by rjmura
Sat Jun 29, 2019 8:15 pm
Forum: Troubleshooting Help
Topic: rtl-sdr lna problem
Replies: 8
Views: 5438

Re: rtl-sdr lna problem

you're right about overloading causing the problem, since i live within a mile or two from am, fm and tv transmitters. am using both am and fm filters, but apparently they are overwhelmed by the strong interference. found that i get best results by using the am and fm filters without an lna, and by ...
by rjmura
Sun Jun 02, 2019 9:24 pm
Forum: Troubleshooting Help
Topic: rtl-sdr lna problem
Replies: 8
Views: 5438

Re: rtl-sdr lna problem

recording of noaa 18 satellite pass with 67 deg max elev was unsuccessful. started off with fm trap to rtl-sdr LNA to rtl-sdr dongle running sdrsharp at 0 rf gain and got nothing but noise. looking at the attachment, the pass starts at the top. the black strip is when i turned off sdr sharp temporar...
by rjmura
Sun Jun 02, 2019 9:31 am
Forum: Troubleshooting Help
Topic: rtl-sdr lna problem
Replies: 8
Views: 5438

Re: rtl-sdr lna problem

managed to get bias_tee_on.bat and bias_tee_off.bat to work by changing -d 0 to -d 1 as suggested by github on mar 2, 2018. must be a windows 10 thing. i'll try to get a satellite picture again tomorrow. may have had the rf gain raised and overloaded. now see that raising the rf gain on the dongle d...