Messages

1

Equipment / Re: Best MWDX antenna?

« on: July 25, 2023, 0857 UTC »

Good point.   I was a bit uncertain about conductivity of the slinky spring material, so I got out my DMM, and checked for the conductivity after joining 3x separate slinky to 1 single long slinky.  The conductivity of the slinky shown on DMM was excellent with loud beeps from the end to the end.  But that doesn't mean it has perfect conductivity I fear.
But it seems doing the job of RXing MW, and even LW, and some portion of HF ok.   It is definitely better than the longwire on some frequencies, but not all.  There are parts of the band, the slinky vertical gets very quiet, when LongWire copies well.   

Great advice on the radials.  Yes the balun is a 9:1 unun, and has only 1 connection post for the radiator, so perhaps some substantial radial wire will have to be added via the coax outer socket via soldering or a crocodile clip.

Through time, I will try getting different balun - with 2x separate connecting posts for the radiator (one for the radials), and keep experimenting.

2

Equipment / Re: Best MWDX antenna?

« on: July 24, 2023, 1312 UTC »

I implemented this Slinky Vertical with 9:1 balun, and it seems working OK on LW MW and 60m tropical band.
It seems definitely working better on MW than long wire.  Good to add another antenna to switch over to, when one antenna gets noisy for the night.

A few videos added into my youtube and twitter channel RXing with the DIY slinky vertical.

3

Equipment / Re: Best MWDX antenna?

« on: July 17, 2023, 0945 UTC »

Thanks for your info. 

I am planning to make a vertical RX antenna covering LW and MW and HF too.  I have a fibreglass  flag pole extending to 7m height = 21ft?
I also found 3x old slinkies in the shed which I am planning to join them all together making into one Slinky, and attach it to the pole.
I am thinking of either feeding via 9:1 balun with no ground input (just radiator input) or  the other balun which has ground input making unbalanced coaxial feeding (which will feed some sort of ground wires).

I also have a MFJ preamp 1020C / Active Antenna which covers 300 kHz - 30 Mhz (actually covers from 250 kHz), which will be using to power the GP.
I am not sure the total length of the stretched 3x Slinkies, but it surely will be higher than 21ft the pole height when stretched due to its wound wire length. Hopefully it will cover from LW to 30 Mhz when powered by the preamp.

4

Equipment / Re: Best MWDX antenna?

« on: July 16, 2023, 0914 UTC »

The 18' end-fed vertical is working decently enough IMHO. I have already worked contacts in NA and SA.

https://www.hfunderground.com/board/index.php/topic,115636.0.html
https://www.hfunderground.com/board/index.php/topic,115688.0.html

I have been thinking about deploying an 18' monopole vertical with a YCCC feedpoint preamp for LW+MW. IOW, I have a S9v18 vertical collecting dust.

What is the frequency cover range on this antenna in reception?

5

Equipment / Re: Grounding receiver ??

« on: July 08, 2023, 0937 UTC »

I tried with with the outer coaxial cable plug out from the radio, and it still was noisy.  This made me think maybe the noise could be in the air or space too, not just indoors or in the garden.  Could it be the HF band itself noisy more so in certain time of day or season due to solar activities or just general band condition?

6

Equipment / Re: Grounding receiver ??

« on: July 08, 2023, 0933 UTC »

I once used a 500 ft. reel of 16 gauge wire from a second floor shack as a common ground for all my radios. I sat it under my radio table, connected it to a copper strip screwed to the bottom of the table, and used ring connectors and screws to connect my radios via short lengths of wire to the strip. It seemed to take care of ground loops and unwanted racket.

Maybe that is what I need for this listening room being 2nd floor high up from the ground.  But 500ft of wire is some serious long length.  I have 4x 30m AC cable extension cables in reels.  One of them has fried itself in the reel where it suppose to shut down for heating up.  Some electronics gone bad, and it started tripping the fuse on the wall, so it is defunct.  The other 3x is functional, but only use 1x of them, so they could be all plugged into each other making up about 120m = about 400 ft ??  length thick AC cable reels.  May try that as common ground for all the radios in the shack here.

7

Equipment / Re: Grounding receiver ??

« on: July 07, 2023, 0844 UTC »

Yeah, really good point and good demo in the link thanks.

So, it seems clear that Grounding receiver is not guarantee for eliminating noise in the reception.  In my case, it made worse.
It was a counterpoise wire through the window to the garden, and the wire coming into the room to the radio ground post was only about 30cm long.  I wouldn't have thought it is long enough wire length picking up common ground interference, but maybe the noise is picked up in outside?  I even inserted a balun between the counterpoise wire and ground post, but didn't make much difference or improvement.

But it is great advice on testing for common mode noise in the coax by taking out the shield bit connector.  I will try that tonight, and see how it turns out.  My random wire with the balun and ATU has been the best antenna for South American LPAM DXing, but the noise is too high.  If I could get rid of  or weaken the noise, I would imagine I could hear a lot more LPAM DX signals on the band.

8

Equipment / Re: Grounding receiver ??

« on: July 06, 2023, 2219 UTC »

Yes, I do use  a 9:1 balun with the random wire.   This eliminates need for separate ground wire for the random wire, as it has only one connection for the radiator.

I had to take out the ground wire to the R71E, because it was not really making much improvement in reception.  If anything, attaching ground wire to the R71E seemed heighten noise in reception, although it also seems making the received signal louder.  But it was not really worth the effort.

So the R71E is now back to where it was, having no ground connection, and just running itself fed by the ATU and random wire with the balun.

9

Equipment / Re: Grounding receiver ??

« on: July 06, 2023, 0948 UTC »

I had a spare balun from China (not sure the specs.  It was cheap £5 from China seller, and bought many months ago, forgot about it) in the drawer, so got it out, and connected the Ground wire from the R71E, and attached a short Coaxial cable through the window.   It seems doing the trick - the R71e got noticeably quieter, but still RXing OK.  Will see how it will perform in DXing noisy band 60m 49m at nights and even MW and LW DXing.

The balun by Chris seems great product.  I suppose SW MD LW DXing is all about well matching impedance of the RX antennas to the receivers.  I have more baluns kicking about somewhere in the house, will try to dig them out, and keep on experimenting.

10

Equipment / Re: Grounding receiver ??

« on: July 05, 2023, 0852 UTC »

Great posts. Thanks for the advice and info.

My radios are on the 2nd floor, which makes difficult to find any good grounding point.  So I ran a 30ft wire as a counterpoise down the window into the garden, and connected the indoor end of the wire to the ATU's Ground input.  The R71E's ground is connected to the ATU's ground.  It seems have got the background noise higher on the reception, but then I could hear a weak LPAM station from Peru (R. Tarma 4775 kHz) louder.  So I just left at that.

My garden does not have any streams or rivers near by, so good ground is difficult to be improvised.  I wonder if the water tap copper pipe under the kitchen sink would make good ground?  It is an old house, and the water tap pipes seems copper and they are a bit rusty.

11

Equipment / Grounding receiver ??

« on: July 04, 2023, 1418 UTC »

Do you connect some kind of ground wire to your shortwave receivers?
I am currently using an old ICOM ICR71E.  It has a connector for Ground / Earth wire at the back.
I am wondering, if some sort of connection should be made to the Ground post.
But how?  Connection to what.  This was my question I couldn't answer clearly.
What is the reason for grounding your receivers?
Does grounding your radios improve DX reception?

12

Equipment / Re: Made in China Wellbrook 1530 Loop Antenna?

« on: May 26, 2023, 1140 UTC »

And on the RF interference problems, if I may add, they might come from many other sources apart from the RX antennas themselves, such as AC power chords, noisy DC PSUs, feed lines, Radios themselves and surrounding environmental EMF sources and domestic appliances connected to AC mains running in the RX houses and properties, and of course the band condition at the RX time, time of days ... etc.  Not a simple issue at all.

Having said that, long wire and random wire antennas tend to be noisier than loop or Mini whips most times.  This is nothing to do with interference, but they just are good at picking up any noise in the surrounding space.  At times, however, LW and RW antennas can copy certain signals better than any other antennas depending on the condition of the band and propagation.  No antennas are perfect for every part of spectrum and band conditions.  Better having more different antennas installed, and try out and opting for the best one for the condition and signal at the time of RXing,  seems good strategy in DXing.

13

Equipment / Re: Made in China Wellbrook 1530 Loop Antenna?

« on: May 25, 2023, 2307 UTC »

I was thinking of buying a real Wellbrook 1530 antenna before it closed down.  But then my Active Mini Whip and Random wire + ATU were doing good DXing LW MW and HF, so I didn't bother.  I used to have a real wellbrook 1530 loop before, and have been DXing with it for about year.  It was good in some part of the band, especially on LW and MW, but on HF, it was similar to much cheaper MLA30.  And there are plenty of ferrite rod, and loop antennas to build and test on LW and MW, which can be more fun.

Anyway, I compared my youtube SWL log copying Myanmar Radio 5985 kHz with the real Wellbrook 1530 loop a couple of year ago, and one I copied this spring a month or two ago with Random wire + ATU.   The random wire were copying 10 times better than the Wellbrook 1530, so I was glad I didn't throw away £300 for another Wellbrook 1530LN.  The old one was sold, when I went QRT, and saving every penny and selling most of my radio gear for funding to buy electric guitars 2 year ago, which I regretted at the time.  But now I feel random wire, Active Miniwhip and even cheap MLA30 will do the same job or even better job provided they are set up well for the environment of RX location.

14

Equipment / Re: Do you get RF jolt? What causes it?

« on: May 07, 2023, 1304 UTC »

Yeah, will turn on the NB on the R71.  It works well on blocking the severe motor grinding type noise, but at the same time it used to degrade received signal audio too.  But the level had to set high level.   Due to that, I tend to not to use it, but setting the NB level to minimum low level might do the trick?   Thanks for your info and advice. 

15

Equipment / Re: Do you get RF jolt? What causes it?

« on: May 06, 2023, 1258 UTC »

I cannot see any trace of single CBers in my neighbourhood - not a single CB antenna is in sight, and none are heard on CB band apart from the DX cbers from Italy or USA when the band opens up.   But lightening and thunder, - right enough, the weather this morning was cloudy and looked like will rain heavily during the day.