Antenna thread

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Channel Hopper said:
With modern processors, almost any frequency can be generated inside the 'modern desktop', it might also be appearing through an open port on the reaqr panel, ethernet, usb or unused video output. There has been additional work done on van Eck scanning since I was involved a couple of decades ago, I'll try to find something (Tempest ?)

Time to put thoose foil underpants to use in the short term though.
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It can escape through any connections, holes below WG cut off and cracks in the case can behave as slot (re-)radiators etc etc. It doesn't surprise me and the levels may be within EMC specs but there's plenty to hear if your wanted signal is -140dBm. Anything before 2011ish wasn't usually tested above 1GHz, now it's 6GHz if if there's a high frequency source inside.

As you say, you need a latter day Tempest enclosure
 
So ..tried moving the Helix closer to focus ...
next to no improvement ...
Tried moving backwards away from focus ...in 1.5 inch stages ...
No change ..
Tried Moving it forwards of the focus ..
A tiny improvement one inch closer ..but certainly nothing to cheer about ..
So imo ...
Either the Helix is deaf or at least hearing impaired ...or there simply isn't enough signal to get at 1.546 ghz ..
(out of footprint)
OR the losses in the RG58 simply cannot be compensated for ..
Basically the Helix is about 2 inches from the focus of a 1.5 mtr offset ...and that isn't enough..
rgds
I will try tomorrow with a shorter cable outside on that slow laptop ...
this may give me some idea of the losses over such a long cable run ...but obviously I cannot use Jaero..
cest la vie
 
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So took a chance dodging between showers ..
Here are 2 screencaps ..
One indoors on the long cable run ..
and one outdoors using the slow lappy and a 2 mtr cable run ..
Looks like the cable is substantially reducing my chances to me ..
ideas anyone ?
...and yes ..that interference is still present ..but you can see the source of the banding to the right of the 3 peaks at a higher frequency ..on the outdoor waterfall..
Roughly 1.546230 ghz
A block of data (similar to pager ) the same width as the band of interference..stretching right accross the visible spectrum..
doh!
 

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Have you tried fiddling with the Horizontal Hold?
 
Also a multiple of 6.184 GHz in overclocking circles.
 
Here's my idea to get around the long cable distro issue ..
Which May or May Not be viable ..
What IF I was to use an RTL dongle outside close to the Helical ..
I am hoping to mod at least one to provide Ghost Power to the LNA ...and use a long cable USB repeater (screened) ...and bring the digital data indoors leaving the RF outside ?
How stable I wonder are these dongles at 1.5GHZ ..??
 
Can I take this as a sign ..that the rain is finally coming to a stop...????DSCF0005.webp

...now where did I put me' shovel ?
 
Amazingly ...
I didn't have to order from the far East ...
Picked up a 20 mtr usb 2.0 active repeater mesh screened cable A male > A Female ..on fleabay ...
£13 delivered ...
It's gotta be worth a go at that price...
 
Now that _was_ quick ..and cheap too ..
Those small ally boxes arrived today via Aliexpress ..
just a nice size for fitting LNA's I think..
rgds
VSDSCF0002.webp
 
Reminds me of when I was a Marconi Apprentice, spending happy Saturdays wandering down the Edgware Road and buying stuff like Die Cast Aluminium Boxes from Henry's.
 
Lazarus said:
Reminds me of when I was a Marconi Apprentice, spending happy Saturdays wandering down the Edgware Road and buying stuff like Die Cast Aluminium Boxes from Henry's.
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Yep

We had similar here in Manchester ..
Mazel radio Liverpool Road ...
Shudehill ..New Cross Radio ...Tib Street ..
Takes me back..
Happy Days..


...Oh ..yeah ..
no shoe leather wasted on this one ..
Sendz components (Shoeburyness)...back cover of Television Magazine ..
A veritable Aladdins Cave..
 
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Lazarus said:
Reminds me of when I was a Marconi Apprentice, spending happy Saturdays wandering down the Edgware Road and buying stuff like Die Cast Aluminium Boxes from Henry's.
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Not Henry's, surely ?

I knew him from when he first started in the industry. Their showroom closed doors just over two years ago.
 
Bought an army surplus Avo 8 - encased in a full metal jacket - from Henry's, that would have been around 1959.
 
Lazarus said:
Reminds me of when I was a Marconi Apprentice, spending happy Saturdays wandering down the Edgware Road and buying stuff like Die Cast Aluminium Boxes from Henry's.
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Do you know another Marconi man from your early days, Paul Marshal .... BATV member , lives over Lincoln way ?
 
Name doesn't ring a bell, but we are talking 1974 to 1979, so memory is by now getting ........ err, getting ........


Oddly, the family home was not far from Lincoln, in those days, near Grantham and another frequent electronics haunt was Birketts in Lincoln. On Steep Hill.
 
I used to habituate places such as these in the sixties and seventies. In Liverpool there was Beaver Radio (which was more hi-fi and components) and another place whose name I've forgotten which more ex-WD and surplus. Later on there was PRS Components which has only relatively recently stopped trading. On this side of the river in Birkenhead there was Bert Ault's and Browning's to browse through.

Oh happy days. Now all sadly gone.
 
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