is there a need for a toroid filter?

. . ok filter may not be the right word, but i am seeing some strange behavior when i try to lengthen the power cable to the ras pi, in order to get the antenna up higher.
. . my adapter jumpers came in today, so it may be a moot point, but i wonder if any others have seen strange activity when extending the power leads? my strange activity was that it simply would not come up and start transferring data.
. . if there is trash on the power leads, might a toroid prevent it from messing up the works?


90% of the problems with Raspberry Pi systems are power related. Most of those fall into one of two categories: cheezy wall warts, and cheezy USB cables.

Cheezy wall warts don’t provide enough current at the proper voltage. You want a good 5V 2A wall wart. Look at Adafruit, Sparkfun, Pololu, places like that.

Cheezy USB cables can introduce significant voltage drop from a wall wart (the kind with a socket) to the Pi. I’ve seen voltage drops of 0.3 - 0.4 Volts at 500 mA. Add the power requirements of the Pi and the SDR and you need solid power.

If you have access to a reasonable and calibrated voltmeter, measure the voltage at the Pi during operation (carefully – shorting things on the Pi can cost you a new Pi). The voltage should be 4.9 Volts or greater.

Look at some of my posts on Pi power supplies – I use a Pololu buck/boost converter with 5V output on pretty much each Pi system. That way I don’t have to worry about wall warts, and I can also power the system from a wider range of supplies, such as LiPo cells, car power, and the like.

Cheap insurance.

bob k6rtm

Wall Wart… Never heard that before. LOL. I like the URL you shared. I like looking and reading your post. I always learn something new or get new ideas to look into or try. Thanks again Bob.

Now i just need to make time and read my book for Ham. I like to get my license. :smiley:

I am always amused at bobs posts also. Always super informative but with a little humor added in. lol

. . ok kinda suspected a strange power problem. so, its a voltage drop problem as opposed to noise or trash on the lines? and, the answer to the toroid question is… no.
. . did u not like the 5v 5a drop down supply, smaller than a quarter? i’m thinking feed it with 12 volts but have the 5 v regulator right next to the ras pi. maybe on top of it.
. . as i mentioned, the mcx/bnc jumpers arrived, heres a pic of the mk 1 mod 1 1090 mhz ground plane. numbers at eleven. tomorrow. oops, scratch the pic, dont know how to link to it, do i embed it in the email with the img html or reference it at dropbox or some such?
. . thanks for the response.


Push 12v up the wire to where the Pi is then use one of these to give you the 5v

Bob (prev post) uses a pair of devices that do much the same thing with POE (Power over Ethernet) - where the otherwise unused pairs in the Ethernet cable are used to take a higher voltage along the wire and it’s regulated to 5v at the remote end … also has the benefit of a proper network connection - not WiFi (which can be troublesome on the Pi)