Search found 51 matches

by Kenn
Thu Aug 22, 2019 1:58 am
Forum: Off-Topic
Topic: ebay sellers beware!
Replies: 2
Views: 1752

ebay sellers beware!

Effective August 1st 2019 ebay has activated a new automated returns system. Buyers can initiate a return for any reason they choose and ebay automatically prints them a return shipping label at the sellers expense. Once returned, the seller has 2 days to refund the buyer or ebay will happily perfor...
by Kenn
Tue Aug 13, 2019 12:38 am
Forum: Antennas
Topic: Folded dipoles and quad loops with SDRs
Replies: 6
Views: 2045

Re: Folded dipoles and quad loops with SDRs

That's right, best way to check is with an ohm-meter. If there's infinite resistance across the antenna inputs you're safe. If it's zero or very low ohms, just be sure you're bias tee is off and you're good. I made a 60" long foded dipole with 300 ohm TV twinlead. It has a 4:1 balun in the center fo...
by Kenn
Tue Aug 13, 2019 12:34 am
Forum: RTL-SDR Discussion
Topic: Newb trying to receive Weather Faxes
Replies: 4
Views: 1426

Re: Newb trying to receive Weather Faxes

I wrote an article about wefax awhile back that might help: https://ranous.wordpress.com/2015/07/03/how-to-receive-marine-radiofax-charts/ It's based on using a shortwave radio. It can be done with an RTL dongle, but a good SW receiver performs better when the signal is weak. The antenna system is v...
by Kenn
Wed Aug 07, 2019 5:25 pm
Forum: Antennas
Topic: Folded dipoles and quad loops with SDRs
Replies: 6
Views: 2045

Re: Folded dipoles and quad loops with SDRs

Yes, folded dipoles and loops are OK to use with SDR dongles. And from the DC resistance perspective, you are correct that it looks like a short. So you want to make sure the dongle's bias-T is off so you don't let the smoke out. :) The bias tee allows you to power antenna side devices like low nois...
by Kenn
Thu May 02, 2019 10:17 pm
Forum: RTL-SDR Discussion
Topic: confused: spectrum analizer and sdr
Replies: 7
Views: 1763

Re: confused: spectrum analizer and sdr

I use a netbook running Linux Mint and Pavel's Spektrum: https://www.rtl-sdr.com/spektrum-new-rtl-sdr-spectrum-analyzer-software/ It'll scan 430-830 just fine. Using 'Relative Mode' is key. With a rubber duck antenna connected directly to the RTL dongle on a short USB cable I can turn the gain down ...
by Kenn
Thu Apr 04, 2019 6:22 pm
Forum: RTL-SDR Discussion
Topic: Do I have latest linux driver?
Replies: 3
Views: 1121

Re: Do I have latest linux driver?

Backing up what Admin and hotpaw2 posted, the Osmocom driver is probably the best all around choice. It seems to work with most apps. I've done some informal experiments with the Keenerd fork of the driver. It seems to work noticeably better with CubicSDR and Spektrum (ie better reception, fewer spi...
by Kenn
Thu Oct 11, 2018 7:30 pm
Forum: Other SDR Devices
Topic: Why Tx/Rx devices are so expansives ?
Replies: 9
Views: 20700

Re: Why Tx/Rx devices are so expansives ?

The rules of mass production I suspect. If there was a demand for SDR similar to cell phones, they'd be mass produced and the unit price would be less.

-K
by Kenn
Tue Jul 31, 2018 2:25 am
Forum: Antennas
Topic: HF Antenna for balcony
Replies: 10
Views: 30204

Re: HF Antenna for balcony

The G5RV antenna is a proven and well regarded antenna amongst hams, but it need 102 feet of space.

The mini-whip antenna, I don't know much about. It's not too expensive, might be worth a try.

You might look at magnetic loop antennas. They tend to be pricey, but are said to work well.

-K
by Kenn
Mon Jul 30, 2018 7:07 am
Forum: Antennas
Topic: Balanced antenna for direct sampling
Replies: 5
Views: 5451

Re: Balanced antenna for direct sampling

Your build looks good, thumbs up! My only concerns would be heat and static. I'd go for a V3 to solve that. I've used TV baluns and RG-6 for many a project, they work fine. The feed-point impedance of a 1/2w dipole is ~73 ohms, super close to RG-6's 75 ohms so you wouldn't even need a balun for that...
by Kenn
Mon Jul 30, 2018 6:35 am
Forum: Antennas
Topic: HF Antenna for balcony
Replies: 10
Views: 30204

Re: HF Antenna for balcony

I had a balcony like that once but only on the 2nd floor. It had a metal railing so I fabricated an angled mag-mount and placed it on the inside so it couldn't be seen from outside. It had a standard 3/8" x 24 thread so I could use all sorts of compact mobile antennas like hamsticks for HF and simpl...