Optiplex GX620 - Dedicated SDR + SAT

[Channel Hopper]

I can post out what I have on Tuesday

 

[Vipersan]

Appreciated buddy ...but only if surplus to requirements..
This project is fast becoming a never ending stream of outgoing cash ..so need to put the brakes on a bit..
lol


I'd appreciate you taking a look at the moonraker in the add ?

 

[Channel Hopper]

Appreciated buddy ...but only if surplus to requirements..
This project is fast becoming a never ending stream of outgoing cash ..so need to put the brakes on a bit..
lol


I'd appreciate you taking a look at the moonraker in the add ?

Looks like the one I have. I bought it some 15 years ago and from memory, it was only suitable for the 900MHz band

 

[Vipersan]

Looks like the one I have. I bought it some 15 years ago and from memory, it was only suitable for the 900MHz band

Cheers CH ..
It does make me wonder regarding the claims made ..
I dont suppose for one minute there is such a thing as a wideband antenna then ..
??
Everything is a compromise ?

 

[battenfan]

Interesting read about the practical problems of making a discone: UHF Discone Antenna
Might need more than one to cover a wide band.
I've seen diys of coat hangers, I'm thinking bicycle spokes.

 

[Channel Hopper]

DISCONE HAM ANTENNA -- ANY GOOD??? | QRZ Forums

 

[Vipersan]

Well ..I guess that answers my question then ...
A thing made to do everything ...does well at nothing ..
lol
unlike my trusty QFH ...made to do a specific job ...and does it well..

 

[Channel Hopper]

Well ..I guess that answers my question then ...
A thing made to do everything ...does well at nothing ..
lol
unlike my trusty QFH ...made to do a specific job ...and does it well..

You will find same at the GHz band. The throat and first stage of a Universal LNB is a compromise of performance against bandwidth, but as long as the transmitter is strong enough to overcome the crap design, what is on the receiving end really doesn't matter.

( I do take exception to 'coat-hanger' technology though, I built many aerials from stuff out of the wardrobe years ago)

 

[battenfan]

I don't feel like buying expensive 50 ohm cable for a toy rtl and a toy coat hanger antenna. For a 75 ohm discone, the cone angle should be reduced.

For broadband operation, the best cone angle depends on band-
width. Given a frequency band from f1 to f2, the optimum cone angle
decreases as the ratio f2/f1 increases. For a nominal 50-Ω antenna, as
the design bandwidth increases from one to five octaves, the optimum
cone angle decreases from 47° to 39°, and the peak SWR creeps up. In
addition, as the feed point design impedance increases, the optimum
cone angle decreases. An interesting implication pursued in some
designs is that the cone should be curved instead of flat sided.
http://www.fars.k6ya.org/docs/All_About_the_Discone_Antenna,_QEX,_Jan-Feb-2007.pdf

I'll probably order some cheap Chinese pre-amps, it would be nice if there were some with balanced input for the qfh.
I have to start making up my mind on what frequencies I want to receive.

 

[Vipersan]

Windows is stealing my resources Grrr ..
Earlier today I tried to get a good weather image of the storm as it moved North and East over the UK ..
sadly not possible on account Orbitron > SDR# > WXtoIMG had the Optiplex running flat out at 100% CPU and half of the available RAM in use ...
Thus the process ground to a halt..
I know that it was possible before ..so what had changed ?
Well since the wifi dongle had been installed ..for no other purpose than TLE and Keppler updates ..windows seized the opportunity to install service pack 1 in my recently built win7 OS ..
Not that I minded this ...until it became apparent that something had changed due to the updates having been installed ..but what ?
Running up task manager with nothing else active ..ie no other program running ...
I took a look at cpu and memory use ..
gulp !! ...cpu was approx 58% used ..and a large chunk of ram ...
deeper investigation revealed svcHost was eating these processes ...and digging even deeper revealed the specific process was windows automatic updates ...constantly running in the background and soaking up practically all the limited resources ..
I turned off svcHost and this got me back to about 2% cpu ..
..but of course the problem returned after a reboot ...so I have totally switched off windows ability to search for and download any further updates ..ignoring the warning ..
After all anything downloaded for installation on the Optiplex is scanned and vetted on my main PC ...and I simply dont want internet access on this unit other than TLE etc.
So hopefully problem solved ...but I still can't get over Microshyte consuming resources at this level without considering the consequences for the end user..
rgds
VS

 

[Analoguesat]

Good idea - otherwise you will end up with windows 10 trying to install on that computer, and probably trashing it.

 

[Vipersan]

As far as upgrading this rather nice SFF dell is concerned I'm now maxed on memory ...so was looking at the cpu..(socket 774)
Installed cpu-z and had a look whats in the box ..
Pentium D 930 which is dual core ...not core 2
Core 2 architecture is not supported ...and I'm already close to max with this ...
I can only now upgrade as far as a Pentium D 960 ....
Question for those in the know ..would this upgrade make much difference ?
The reason I ask is that the D960 is like hens teeth ...so getting one might be an issue.
But if the upgrade is worthwhile ..I'll keep looking.
rgds
VS

 

[Channel Hopper]

As far as upgrading this rather nice SFF dell is concerned I'm now maxed on memory ...so was looking at the cpu..(socket 774)
Installed cpu-z and had a look whats in the box ..
Pentium D 930 which is dual core ...not core 2
Core 2 architecture is not supported ...and I'm already close to max with this ...
I can only now upgrade as far as a Pentium D 960 ....
Question for those in the know ..would this upgrade make much difference ?
The reason I ask is that the D960 is like hens teeth ...so getting one might be an issue.
But if the upgrade is worthwhile ..I'll keep looking.
rgds
VS

You broke it inside a fortnight ?

 

[Vipersan]

You broke it inside a fortnight ?

Must be slow this morning ..
doh!
Must have missed something ..
broke what exactly ?
lol

 

[Vipersan]

Finally got internal usb connection sorted ..
Actually ..x 2
Having tested and modded quite a few unsuccessfully ...I now have a worker.
Turns out USB 1.0 simply wont work with SDR ..
But I WAS surprised when USB 2.0 failed also ..
After much digging the refusal of SDRplay to even be recognised by USB 2.0 on a pci card turned out to be a chipset incompatibility..
The reason for this incompatibility is that VIA based chipsets of the type VT6212 on close variants are NOT fully complant with usb 2.0 protocol ...using bulk transfer and not Isochronous transfer ..
Thus bandwidth is severly restricted ..and thus the SDRplayer refuses to even be recognised..
full story here :-
SDRplay incompatibility with usb 2 pci card ? - SDRplay Community Forum
So I eventually got my hands on a used NEC chipset based pci card (usb 2.0) cheaply ...but not a low profile one..
It arrived this morning and as expected would not fit ..even with the backplate removed..
It's just too tall ..
Out came the junior hacksaw and the topmost usb socket sacrificed..
There are 5 ports in total ..
One internal ..and 4 to the rear ..now 3 to the rear ...but the only low profile backplate I have is from a 2 port card ..
So the 3rd from the bottom usb port socket was removed reversed and repositioned to point inwards ..
I now have 4 ports available ..2 of which point outwards ..and 2 internal ...and now the 2 port low profile back plate will fit ..
I'm attaching photos of the modded pci card..
All this to make a neater job..
lol
but I guess thats the fun of it..
rgds
VS

 

[Vipersan]

So I guess it 's a lot to ask ...but the Optiplex is coping ...
I'm amazed tbh..
Currently processing RTL1090 data ...on the top screen (using an RTL nooelec dongle)...and receiving and decoding a weather image from noaa15 on the bottom screen ..using the SDRplay..
Cpu is pulling double shift but is still mostly around 80%

 

[archive10]

Installed cpu-z and had a look whats in the box ..

be careful with cpu-z... it's well known to be a "open port" for adware and trackware connections.
I wondered, then read the small print in the license agreement, then uninstalled it.

 

[Vipersan]

Guess I'll have to start a new thread now ...
The optiplex 990 has arrived...
Just about to test it ..
rgds
VS

 

[Lazarus]