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Strange signal in 80m CW section?

Max
 

Sorry a bit off topic, but as the group seems a little quiet at the moment, can anyone tell me what this signal might be, 3534 kHz?

Screenshot attached.

 

G3TDJ
 

Looks like a Link 11 transmission, dual sideband

https://www.sigidwiki.com/wiki/Link_11

Kriss Kliegle
 

Might help if you gave us more than your screen name...

What's your location?
Time of day?
Quality of antenna, i.e. 80M inverted Vee at 100' or slinky antenna hung in the attic next to the solar panels and associated charge controllers?

Make an IQ recording and attach it so we can all hear and see it.

Kinda looks like Pactor:
https://www.sigidwiki.com/wiki/Category:HF

73 Kriss KA1GJU

Max
 

Yes, fair point Kris.......  UK south coast (nr Eastbourne) and appalling antenna...... 40ft unmatched end fed, but still a strong signal.

....but G3TDJ...... looks spot on..... amazing knowledge in this group.....

Many thanks. Curiosity sated!

Kriss Kliegle
 

If you have the room... try and end fed wire (EFW) of 124' with a 9:1 UNUN. I use this setup on most of my servers, plays very well from DC to Daylight! :)

Yes, there's a plethora of talent here on the list! :)

73 Kriss KA1GJU (Southeast NH, 35 miles NNE of Boston, MA)

Max
 

Kris. I have decided to stay away from end feds as I have a noisy house (as do most these days I imagine) with plethora of SM PSUs on nearly every bit of kit in the house.

So for low noise I have plans for 250ft doublet fed with 450 ohm ladder line and external antenna matching unit or remotely switched feeder lengths. Whether I get around to it is yet to be seen!

Used to have full sized G5RV many years ago and that worked very well (different location). I note that Hack Green has double length G5RV and that always seems to work very well, hence my interest in long doublets.

http://hackgreensdr.org:8901/
http://www.w5dxp.com/owt3.htm
http://www.w5dxp.com/notuner/notuner.HTM

73

Max

doug
 

On 10/10/2019 01:53 PM, Max via Groups.Io wrote:
Kris. I have decided to stay away from end feds as I have a noisy house
(as do most these days I imagine) with plethora of SM PSUs on nearly
every bit of kit in the house.

So for low noise I have plans for 250ft doublet fed with 450 ohm ladder
line and external antenna matching unit or remotely switched feeder
lengths. Whether I get around to it is yet to be seen!

Used to have full sized G5RV many years ago and that worked very well
(different location). I note that Hack Green has double length G5RV and
that always seems to work very well, hence my interest in long doublets.

http://hackgreensdr.org:8901/
http://www.w5dxp.com/owt3.htm
http://www.w5dxp.com/notuner/notuner.HTM

73

Max
Well, you are certainly right about noise. I have a 50 foot end-fed up around 18 feet, 9:1 balun, and on 40 meters the noise is between S8 and S9! I don't have room for a longer antenna aimed east-west (I'm in Long Island, NY). I had a center-fed dipole aimed north-south that worked pretty well, but the direction was wrong, and then the town came along and cut down the tree at the west end of the dipole!

I wonder how you explain the susceptibility of the end-fed? It's not obvious to me.

--doug, WA2SAY, retired RF engineer

Max
 

Is it not the same as for all balanced cables, audio mic/line cables or CAT/RJ45 cables for example? The local noise gets in on the feeder where it is closest to the source (as it approaches the building in our case), but with a balanced feeder local noise is anti-phase on each leg, hence cancels?

That is how I have always assumed it to be but maybe there is more to it than that?

Max

Kriss Kliegle
 

Yes, my end fed wire is noisier than a resonant dipole. But I did find by mounting it higher, the noise floor improved dramatically. I have two 124' end feds between two Rohn 25 towers. One at 50' and perfectly level to the 50' mark on other tower. The other at 100' and heads over to the other tower, but at the 128' level.
I have another on AirspyHF #1, but it's at only 30' AGL and it's the noisiest of all three.

I have also tried to reduce the noise with a common mode choke from here:
https://palomar-engineers.com/ferrite-application-experts-2#!/Coax-Noise-Filters/c/24774281/offset=0&sort=nameAsc

No change noticed on panadapter what so ever. There was a hint of a decrease on 10M, but that was it.

As for noises in the house, those are relatively easy to hunt down thanks to SDRC. The ones I found here were the Ethernet cables, cordless drill charger, daughters touch lamp, laptop power supply, halogen lamp with dimmer, solar charger for backup diesel genny battery, 5V USB PS for the over the air antenna amplifier, and the Whirlpool Duet clothes washing machine. All of which were cured via toroids, AC line filters, swapping out with a quieter unit, or taken out back and shot.

Here's just a few of my wire antennas three more are locate near the house to the far left:


My SDRPlay server is on the upper EFW, and SDR-iq #2 and AirspyHF Discovery #2 servers are currently on the 160M vee.
Oh, forgot one more RFI issue, the electric fence when weeds and grass gets too high can create pulsing at 1 second intervals.

73 Kriss KA1GJU

Graeme Zimmer
 

I have decided to stay away from end feds as I have a noisy house
My trick is to use a balun with isolation, eg a no DC connection through it.

The isolation blocks the conducted noise from inside the shack.

It's just a toroid transfomer with a small link winding to the receiver.

Also the transformer has switched taps to change the impedance for each band.


......Zim