BIAS-t over RG6?

[wowologist]

Any problems with that? (other then the obv. connector 75/50ohm mismatch)

I've had a chi-com mini-whip in a shoe-box for like 10 years and thought...hmm let me put this up at about 40' and use this 100' of RG6 (quad shield-solid center) I've had gathering dust for about the same amount of time. Going to mount the mini-whip in a 1L bottle up on the mast and then water tight the bottom where the RG6 exits.

 

[vagrant]

No problem putting volts through a 75 Ohm cable. Test it with everything hooked up on your kitchen table or whatnot before you put it in the air and string the cable. I presume the BIAS-T is the one that came with the mini-whip, so numbers should be good.

Once you do string it up, I'm figuring you'll use an AC wallwart for the DC power. You should also test it with a battery and feed it DC. When you do, check to see if it removes some noise or not. Some A/B comparisons on WWV at 2.5, 5, and 10 MHz. Then tune to some dead freqs on different bands and do the same A/B test. While an antenna will pickup noise, wallwarts can be your worst foe.

 

[Ubbe]

RG6 are usually the coax used for a sat dish, that gets their LNB heads powered with 12-15 volts thru the coax from the receiver box.

Bias-T are just a coil connected to the coax with enough Henry to stop the RF from being shortcircuit and are connected to a power source. The coil needs to handle the current needed to power the device at the other end of the coax. There are cheap 5volt bias-T that powers active TV/Radio antennas that can be used. As mentioned it's nothing fancy and you can take a $5 sat CATV splitter where one port have power thru and stick a choke coil in that port and solder or twin a cable to it to a power source that either use current limit or use a low ohm resistor or a fuse to protect from shortcircuits.

/Ubbe

 

[wowologist]

Ya hey all, thanks for the input!

I set it up and wow this little thing I swear receives dragonfly wings flapping by; its literally sucking everything in - which is what I wanted, as now I can take that signal and listen to the slices of filtered/DSP'd goodies that I want. The injector that came with it says 8v to 15v - and seems to work best at around 11.2v @ about 142ma, any higher seems to bring the noise floor up so high that you can't even filter out to look at the signal you want.

 

[rk911]

nope...should work very well. i use RG-8X for everything in the shack...just easier to buy it in bulk.

 

[wowologist]

nope...should work very well. i use RG-8X for everything in the shack...just easier to buy it in bulk.

Ya I'm lucky enough to have 2 1500' spools of Belden RG-8/U soft flex that got left in my hanger after the gulf war. I pretty much use that for everything since it handles QRO to QRP to jumpers like candy since it has a 4" bend radius and is solid copper throughout. +/- 1db loss at 300' for this little listening project I thought I'd use up the useless RG-6 Quad shielding since I was more concerned about interference ingress and it works pretty good!