Most recently I have had problems keeping my Bias T voltage active out to my LNB. It turned out that the Dreamcatcher overheated because I had the bottom (shown below) facing down against my EasyAcc battery pack. The container stayed a reasonable 97degree F, but the bottom got extremely hot to the touch.
After flipping the Dreamcatcher over so the clear plastic cover set on the EasyAcc, the bottom of the board no longer got hot to the touch, and I am no longer experiencing the problem. I thought I’d share this problem/solution if anyone else has been experiencing unexplained loss of Bias T voltage. Ken
I wonder if this is why my dream catcher after a reboot doesn’t work and it needs to sit off for a few minutes before I turn it back on and it works. I wonder if It could be a heat related issue.
Something to consider. Check by touching the bottom of the Dreamcatcher board after it’s run OK for an hour to see if it’s hot to the touch as mine was. Ken
I changed the title of this post to MAYBE SOLVED - - here’s why
My Dreamcatcher v3.03 is set up 500 feet away from my Maverick LNB mounted on an 80 cm offset Ku band reflector with one or two 20 dB in-line satellite amplifiers. The Dreamcatcher is driven by an EasyACC power bank. While heat has been an issue, Jerry @maxboysdad and Syed @Syed have asked me to perform a number of voltage and current measurements suspecting that my input 5 vdc to the Dreamcatcher may be dipping too low. Here are the most recent measurements:
One in-line amplifier
DC input to board 5.03 vdc, current to board 1 amp; Rssi -94 dBm, SNR +8 dB with .1 amp of 14.2 vdc Bias T
Two in-line amplifiers
DC input to board 5.03 vdc, current to board 1 amp; Rssi -75 dBm, SNR +8 dB with .13 amp of 14.2 vdc Bias T
No in-line amplifiers resulted in no lock with no reception
DC input to board 5.03 vdc, current to board .9 amp
Finally with the two in-line satellite amplifiers, I am now set up with a 2.4 amp 5 volt power cube delivering 5.07 vdc DC input to the board drawing 1.0 amps. LNB current and Bias T voltage remain the same as before. I don’t know if this higher board input voltage is critical as it is only .04 vdc higher.
Due to my configuration, I need the two in-line satellite amplifiers to deliver sufficient Rssi levels to the Dreamcatcher. The Dreamcatcher’s low end threshold is below -90 dBm (although I have achieved LOCK at levels of -94 dBm).
Please chime in if you think my power cube is delivering too low a voltage. Ken
I would reserve judgment until you have run it a few days to see if it will consistently hold at 5.07. Providing that the power cube holds to that voltage after “burn-in time” of a week or two, I would say you have solved it.
I think we can safely say that heat applied to the board, even from an external source, can cause the Dreamcatcher to fail, as Jim, Ken, and I have experienced in several different situations.
Question for @Syed: Has the design group performed any destructive testing to check the limits of how high the source voltage can be before destroying parts on the Dreamcatcher 3.05?
Recently several of my 5v (2.5a and 3a rated) power cubes powering my raspberry pi 3+ boards have slowly dropped in output voltage. This is a real problem with the rpi 3b boards that cause them to stop/reboot continuously. This was after about 12 to 18 months of operation.
These power cubes replaced my original rpi power supply that had output voltages dropping to 4.7vdc with load when the rpi 3b+ boards were initially sold. I even bought some rated at 5.1v or 5.2v. (Note the newer rpi 4 boards with the usb-c are not as sensitive to power supply voltage).
Second thought… i think the bias-t power requirements are really very low (even with two in-line amps and the lnbf). If that is suspect, a simple bias-t dc blocking and injector could be used to replace the dreamcatcher onboard power source. I think these injectors have been previously covered in the forums.
Third thought… yes I had two of my dreamcatchers (ver 3.03 or earlier I think) fail when one of the power regulator chips overheated… I burned my finger touching it … twice…
This chip was a regulator supposed to provide the on-board power regulation for most of the 3.3vdc or 5vdc loads on the dreamcatcher. I did not try and fix the boards… I just bought replacements.
Thanks, Jim. Yes, I had a similar situation with the first power brick I was using. It was sufficient to the task when I first connected it, and it did hold very well for about 1-1/2 years. I eventually started experiencing odd failures with the Dreamcatcher, and decided to monitor the voltage with a recording meter. On first test with a digital meter, and several subsequent tests, the voltage measured slightly over 5v, and the problem appeared to be something else. However, once I put the recording meter in line, it showed that there was a “sag” in the 5vdc down to 4.9vdc that was occurring a couple of times each day. Once I changed out the power brick for a brute force 12volt supply running a down converter, the symptoms of trouble all disappeared. The output of the downconverter I am using is 5.3 volts, is capable of 5 amps, and the input to it can vary from 6 to 26 volts dc and not affect the output. Very reliable.
Question for @Syed: what are the voltage input limit specifications for the voltage regulation circuit on the Dreamcatcher v3.05?
Yep - - these chargers are real pain, Jim. My original problem developed when my EastACC power bank started delivering levels below 5 vdc. It was powered by a dual 4.8 amp 24 watt Icleaver power cube.
I’m now directly powering my Dreamcatcher (DC) from the Icleaver. After one day (I know 2 weeks would be a better burn-in), I’m still reading 5.06 vdc to the DC. So, we shall see.
I have a 5.1 vdc 1 amp cube, but it won’t drive the DC. I plan on buying a 5.25 vdc 2.4 amp Raspberry Pi power cube which are available on-line for less than $10. Ken
Thanks all - - we all need to become aware of this voltage issue. Not only current limits - - USB power cubes producing less than 1 amp charge won’t run the Dreamcatcher - - but USB power cubes (as Jerry and I have discovered) start out strong, but degrade over time. I have had some chargers on my phones go bad too.
In the past few weeks, there have been several posts about Dreamcatchers not working. The answer may be this voltage issue that is hard to measure on the board. Ken
When shopping for a power supply, one of the key things to look for can be the word, “regulated”. The unit in Jim @ac8dg’s post does advertise that it is a regulated supply. This means a constant output voltage not dependent on load. This is similar to the output of an up- or down- converter unit, such as is used for the bias-tee voltage in the Dreamcatcher’s lnb circuit.
I don’t know how convenient it is for you, but one accessible place is just behind the microUSB connector. The two outside pins are voltage and ground.
I have a recommendation for measuring voltage and current on USB-A end of your power cables.
I have personally used one of these for over a year, with good results. Cost is about $14 US:
