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Author Topic: Propagation Path or Equipment?  (Read 2085 times)

Offline alpard

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Propagation Path or Equipment?
« on: July 01, 2020, 1428 UTC »
I have been trying to receive this DX station, Radio Korea on 15575 Khz, but it is very very faint weak most of the days. Some days it could be heard with just good enough to make out what they are saying, but mostly it is too weak to copy.

But when I go to a KIWI SDR site which is located about 500 miles south of me, it receives it mostly fine. It is not super strong signal, but it can hear 100% of the contents.

So, what is it? Is it my equipment? My antenna is about 30 m length of wire in the garden, and I have ATU and Preselector and Active antenna.  But today, I connected all of them up to boost the sensitivity and the reception on the signal, but couldn't hear it.

When I go to the kiwi SDR site, it hears the signal very well.

Could it be the propagation of the path, that the signal is not quite coming into my area? Or could it be my setup = radio and the antennas?

ICOM R71E, Lowe HF-225, YAESU FRG100, TECSUN PL-330, PL-320, XHDATA D-109, D-808, MSi001 SDR, AOR AR3030, Sangean ATS803, ATS-909X, Antenna= Random Wire+ATU, Active Miniwhip

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Offline ChrisSmolinski

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Re: Propagation Path or Equipment?
« Reply #1 on: July 01, 2020, 1434 UTC »
It could be propagation as 500 miles can sometimes make the difference, but it's most likely it's the antenna. Which KiwiSDR did you use, and what antenna do they have?  A 30m/100 ft random wire antenna is OK for fairly strong signals, but not for the tougher/weaker catches. Also what receiver?

Another potential issue is local RFI masking the signal.

What is your QTH? You need to find the ideal time/freq to hear Vo Korea for your location, for the time of year and where we are in the solar cycle.

I actually happened to listen to their 11710 transmission this morning around 1348 UTC, with a pretty good signal here in MD.
Chris Smolinski
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netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 900 ft Horz skyloop / 500 ft NE beverage / 250 ft V Beam / 58 ft T2FD / 120 ft T2FD / 400 ft south beverage / 43m, 20m, 10m  dipoles / Crossed Parallel Loop / Discone in a tree

Offline alpard

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Re: Propagation Path or Equipment?
« Reply #2 on: July 01, 2020, 1520 UTC »
The KIWI SDR site uses the Wellbrooks Loop, but sometimes very very rarely it cannot receive it either, I just remembered. But most days it hear it very well.

My QTH is northern part of UK, and the SDR site is in Southern UK.

Yeah, I can see your point on the propagation path causing it, because sometimes I hold my XHDATA D-808 with the whip antenna, and when I move around in the room, on some spots it hears weak stations very well, but by just moving away a few steps further, it totally loses it.

My receivers are a few, but mostly I use a Sangean ATS-803A, Realistic DX-392, and ICOM IC-751A transceiver, TECSUN PL-660 and XHDATA D-808.

I will try 11710 Khz, if timing is OK with me.  But I seem to hear better on 9515 and 9740 for RK schedules which is late afternoon and evenings.  But this 15575 has been always very very difficult copy due to the weakness in signal.  I was wondering if my antenna needs some height at least about 10m above the ground and clear? Because my 30m long wire is only about 1.8m above the ground being also used as drying washed clothes.

« Last Edit: July 01, 2020, 1522 UTC by alpard »
ICOM R71E, Lowe HF-225, YAESU FRG100, TECSUN PL-330, PL-320, XHDATA D-109, D-808, MSi001 SDR, AOR AR3030, Sangean ATS803, ATS-909X, Antenna= Random Wire+ATU, Active Miniwhip

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Offline ChrisSmolinski

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Re: Propagation Path or Equipment?
« Reply #3 on: July 01, 2020, 1551 UTC »
The 751A is probably the best radio to use. 11710 works for me at that time, but may not be ideal for you. My suggestion would be to find all the available transmissions, even the non English ones for now, and try all of them to see which comes in best, if at all. That may help you narrow down the best ones for further monitoring. Keeping in mind things can vary day to day, on top of seasonal and solar cycle variations.
Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 900 ft Horz skyloop / 500 ft NE beverage / 250 ft V Beam / 58 ft T2FD / 120 ft T2FD / 400 ft south beverage / 43m, 20m, 10m  dipoles / Crossed Parallel Loop / Discone in a tree

Offline alpard

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Re: Propagation Path or Equipment?
« Reply #4 on: July 01, 2020, 1628 UTC »
Yeah, the 751a is still a good radio, but the XHDATA D-808 impressed me too. And the Sangean and Realistics are not bad either. So is the PL-660 from TECSUN.  OK, the Realistic DX-392 is a bit struggler when it is tuned to the weak 15575 kHz RoK compared to the other radios.

Yeah, it is not the antenna, because there are definitely days that the Wellbrook Loop powered KIWI SDR sites cannot copy it either depending on the propagation on the day.  But it seems the WELLBROOK Powered SDR site has been more consistently receiving the 15575 RoK  well.  I have been monitoring the site for many days now for the program. Also I think that the Wellbrook loops is about 15m above the ground clear from any obstruction.  But then there are guys running the Wellbrook loop attached to the wooden fence in the garden almost ground level, and working all the DXes.

What is the best SW schedule site? The one I am using is, these ones

https://www.short-wave.info/index.php

https://shortwaveschedule.com/index.php?freq=15245

I was wondering if there are something better = more up to date and accurate.

« Last Edit: July 01, 2020, 1631 UTC by alpard »
ICOM R71E, Lowe HF-225, YAESU FRG100, TECSUN PL-330, PL-320, XHDATA D-109, D-808, MSi001 SDR, AOR AR3030, Sangean ATS803, ATS-909X, Antenna= Random Wire+ATU, Active Miniwhip

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Offline ChrisSmolinski

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Re: Propagation Path or Equipment?
« Reply #5 on: July 01, 2020, 1641 UTC »
What is the best SW schedule site? The one I am using is, these ones

I was wondering if there are something better = more up to date and accurate.

Well I am partial to the one built into DX ToolBox, probably because I wrote it  :)  https://www.blackcatsystems.com/software/ham-shortwave-radio-propagation-software.html

Coincidentally, I am currently working on a real time schedule page for the HFU, it is still under development, but you can play around here: https://www.hfunderground.com/on_the_air/update.php
Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 900 ft Horz skyloop / 500 ft NE beverage / 250 ft V Beam / 58 ft T2FD / 120 ft T2FD / 400 ft south beverage / 43m, 20m, 10m  dipoles / Crossed Parallel Loop / Discone in a tree

Offline alpard

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Re: Propagation Path or Equipment?
« Reply #6 on: July 01, 2020, 1712 UTC »
Thank you for the link. Yes will visit there, and see how it goes.
By the way, the Kiwi SDR site uses a WellBrook ALA100LN Loop.

Your radios & antenna system look impressive too. Great stuff.
ICOM R71E, Lowe HF-225, YAESU FRG100, TECSUN PL-330, PL-320, XHDATA D-109, D-808, MSi001 SDR, AOR AR3030, Sangean ATS803, ATS-909X, Antenna= Random Wire+ATU, Active Miniwhip

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Offline ChrisSmolinski

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Re: Propagation Path or Equipment?
« Reply #7 on: July 01, 2020, 1807 UTC »
Yeah, it is not the antenna, because there are definitely days that the Wellbrook Loop powered KIWI SDR sites cannot copy it either depending on the propagation on the day.  But it seems the WELLBROOK Powered SDR site has been more consistently receiving the 15575 RoK  well.  I have been monitoring the site for many days now for the program. Also I think that the Wellbrook loops is about 15m above the ground clear from any obstruction.  But then there are guys running the Wellbrook loop attached to the wooden fence in the garden almost ground level, and working all the DXes.

I would not immediately rule out the antenna you are using just because the KiwiSDR cannot receive the station on some days. Being able to receive a station depends on a few things. First there's propagation, is the signal actually reaching your area from the transmitter, and how strong is it? Then there's the receiving setup, antenna and radio. Along with local noise levels.

If you check out a number of KiwiSDRs, which all use the same radio of course, you will see a huge variance in their quality, how good they are. This is a function of the antenna as well as the local noise levels. They could be in a RF quiet area but have a lousy antenna. Or they could have a great antenna but be in a very RFI filled environment. Or both  ;D  Either means poor reception. And of course most antennas are good only on some (maybe small) part of the spectrum. It could be great on the lower bands but terrible on the higher bands. Or vice-versa.
Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 900 ft Horz skyloop / 500 ft NE beverage / 250 ft V Beam / 58 ft T2FD / 120 ft T2FD / 400 ft south beverage / 43m, 20m, 10m  dipoles / Crossed Parallel Loop / Discone in a tree

Offline chanito

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Re: Propagation Path or Equipment?
« Reply #8 on: July 01, 2020, 1907 UTC »
DX Toolbox looks to be a lot of bang for the buck. Wish I'd noticed it earlier.


I use Dxtreme begrudgingly purchased solely for the click to tune Station Checker functionality that I missed after the king of shortwave tools, Bob Sillett N3OEA's "Shortwave Log", stopped working after Win 7. Not into logging as much as hunting and listening here.

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Offline Josh

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Re: Propagation Path or Equipment?
« Reply #9 on: July 01, 2020, 2017 UTC »
Not much can beat a vertical antenna for dx. Verticals offer an improved low angle of reception over a horizontal antenna.
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Offline alpard

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Re: Propagation Path or Equipment?
« Reply #10 on: July 02, 2020, 1527 UTC »
Yeah,  my long wire antenna could be modified for something else such as into a Loop. I am looking into this project.

But yes, vertical antenna had been in my mind too.  But what I was surprised with my portable XHDATA D-808 is that when I walk around in the room with the radio on and only with the whip antenna, it can receive very difficult to copy signals at one spot, usually near the window, but not always. Sometimes it happens right in the middle of the room, and it copies the signals my ICOM struggles to copy with the outside long wire. But as soon as I move one step away from the spot, it loses it.

But for the 15575, I mean I used to copy it ok before. But recently it got very very weak. And today, again no reception, but a very strong VOA which was supposed to be on 15580 was heard on 15575 wiping out the faint trace of the Radio Korea signal.  So I gave it up.

But guess what, I copied a very rare DX last night with the same set up and radio. It is Zambia NBC Radio 1 from LUSAKA Zambia on 5915 kHz, and it was good signal. I couldn't believe it. I was quite happy with that.  I put that into my twitter account.

https://twitter.com/gm0mop/status/1278419467492605952
ICOM R71E, Lowe HF-225, YAESU FRG100, TECSUN PL-330, PL-320, XHDATA D-109, D-808, MSi001 SDR, AOR AR3030, Sangean ATS803, ATS-909X, Antenna= Random Wire+ATU, Active Miniwhip

https://twitter.com/RadioPax88
https://www.youtube.com/@RadioPax88/videos