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Messages - IQ_imbalance

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106
I've got it on 9580 but very weak.  Can make out voices but no intelligible copy.

107
SDR - Software Defined Radio / Re: RPi Ethernet question
« on: June 21, 2020, 1345 UTC »
Yep...direct connection.  The idea is to use an instance of icecast running on the RPi to stream the device’s (it’s a radio btw) audio wirelessly.

You being up a good point...while the Ethernet port on the RPi should autosense (they’ve done that for awhile) it’s possible something is wonky there.  Wouldn’t matter on the Mac since it would take up the slack, don’t know about the device’s own port.

I should try plugging in my afedri to the RPi and see if those two can communicate....

108
SDR - Software Defined Radio / RPi Ethernet question
« on: June 21, 2020, 0338 UTC »
So if I’m connecting a device with a static IP directly to my RPi via Ethernet, any speculation why it wouldn’t be detected?  I know the cable is good, I know the Ethernet is good (I can ssh into the RPi from my mac), and I know the device is fine (i can ping it from my macs Ethernet port).  There’s something about the damn RPi configuration that’s just not meshing...I even checked that the device and the RPi have the same subnet mask.
Any ideas?

109
General Radio Discussion / Re: RPi based ham radio wall clock
« on: June 20, 2020, 1439 UTC »
I didn’t notice this was from CSI. I know them from xephem, which is an awesome cross platform  astronomy program.

That said...I wish I could justify buying a real geochron.  Those things are just iconic.  They make a cheaper black box version that you plug into a monitor, but the mechanical version is just awesome.

111
Equipment / Re: RF circuit help....
« on: June 16, 2020, 1641 UTC »
My NanoVNA finally arrived.  As expected, the diplexer chops down on the 200-400Mhz sensitivity. The top scan is my DJ-130, the middle scan is the UHF (~800-900 MHz) yagi, and the bottom is the combined feed from the diplexer.  What's curious is that the amount of attenuation around 300 MHz doesn't appear too massive (within a log at least) yet i've lost a 380 MHz system.   Still playing around with it.....

112
Equipment / Re: RF circuit help....
« on: June 12, 2020, 1450 UTC »
A VNA is in my future.  Going to have to make some educated guesses about the component values as they’re not marked but we’ll see.  Given that the only UHF I’m really interested in is toward the upper limits of the current configuration hopefully I’ve got plenty of room to tweak the VHF section without affecting UHF

113
Equipment / RF circuit help....
« on: June 12, 2020, 0219 UTC »
Hi all.  I purchased a diplexer so i could run a VHF and a UHF antenna into the same feedline.  Seems to work well, but I didn't notice that there's a gap between the two bandpasses (VHF 47-230 MHz, UHF 470-862 MHz).  Unfortunately there's a 350 MHz system i'd like to receive, so I'm wondering if i can tweak the circuit to fix this...ideally by shifting the VHF bandpass from 47-230 MHz to 47-400 MHz (or thereabouts). 

I did my best to trace the circuit (damn tiny surface mount components!!!)  Can anyone make heads or tails of this, and suggest somewhere i might start to try and figure out how to modify the VHF bandpass?  I'm fine w/ the UHF settings, so hopefully i just have to do something to the VHF leg.


114
Equipment / Re: Vertical antenna build questions
« on: June 06, 2020, 1754 UTC »
Don't forget to weatherproof the elevated end like crazy (and a drip loop might still be a good idea) if you're using F-connectors and RG-6.  Ask me how I know.....

115
Equipment / Re: Up the discone!!
« on: June 06, 2020, 1752 UTC »
....and it wasn't the 550 cord.  Turns out i didn't waterproof my connectors adequately and while it works great at HF and VHF, it's practically deaf on UHF (~800MHz).  I can see a weak signal on my afedri but it's not nearly good enough for my scanner to decode.  Tried whacking a few feet of coax off the ends but still no-go.  Going to scrap the coax (no big deal, picked up several hundred feet for cheap) and start again once I get some additional coax-seal...apparently 'waterproof' F-connectors only do so much.....

116
Equipment / Re: Vertical antenna build questions
« on: June 06, 2020, 0241 UTC »
Probably doesn't matter, but ran into this while researching how to insulate my hanging discone...

http://www.repeater-builder.com/antenna/tree-antenna/tree-antenna.html

There's some fellow near Glenelg that has one of those fancy 4-corner vertical setups, along with a whole host of other antennas

The countryside in that part of MD is thick with folks from (ahem) places w/ lots of RF experience......

117
Equipment / Re: Up the discone!!
« on: June 06, 2020, 0236 UTC »
another lesson learned.  550 cord is a great RF insulator while dry, but when it gets wet...not so much.  Was wondering why everything got quiet after a few rain showers....

Will install a PVC insulator to deal with this issue tomorrow.

118
Equipment / Re: Up the discone!!
« on: June 01, 2020, 1612 UTC »
Some additional data....apparently the DJ-130 can survive free fall from about 40' onto a deck.  20lb test line does NOT hold up well.

Good news though, the 550 cord arrived and i used it to hoist the antenna back up.  As long as the squirrels don't eat it, and the branch holds, I think i'm in a good place.


119
Equipment / Up the discone!!
« on: May 15, 2020, 0010 UTC »
Today I started my little project to get some elevation on my DJ-130 discone.  It’s been mounted on a 2nd floor deck, but I want to try and raise it above the roofline if possible.

Its new home will be a tree so I broke out the fishing pole, lead sinker, and slingshot. I was pleasantly surprised to manage to get the line on a decent branch without the lead sinker breaking any windows or heads.  So far so good....

Next was to swap the 20lb test for something more substantial.  Unfortunately the 550 cord I thought I had was nowhere to be found beyond bits and pieces, but nowhere near the length necessary.  Amazon to the rescue, but that means it’s in a holding pattern for now.

120
SDR - Software Defined Radio / Re: SDR recommendation......
« on: May 13, 2020, 2350 UTC »
I'll second the afedri recommendation...very happy w/ mine (it's the HF/VHF version).

With 5 acres you could set up a pair of loops and phase them....that might be fun. 

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