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Re: Conditions 07/11

Posted: 08 Nov 2018 13:29
by John Faulkner, Skegness
Quite simply, it wouldn't match. But this is not a helpful answer.

From experience, it will reduce gain, probably more noticeable at one end of the band than the other. It will certainly screw up the receive pattern. The resister value would also be affected to some degree as it would need to match, but match what? The circuit is now wrong and nothing matches. You may still be able to obtain some kind of null, but it won't be the optimum null possible due to the mismatches.

Re: Conditions 07/11

Posted: 08 Nov 2018 13:35
by tvdxrools
all the balun is doing is bringing down the high ohms on the antenna to match your coax at the feed point ie 50 or 75 ohms nothing more , try winding your own one its easy to do , just get a ferrite ring and put 48 turns on one side and that goes to the flag and 11 turns on the other and that goes to the coax , David
ps if your are not using the correct value as john says it wont be a match and you will hear stuff but not as good as a matched one

Re: Conditions 07/11

Posted: 08 Nov 2018 13:45
by John Faulkner, Skegness
Surely it should be 3:1? My flag balun is 18 turns one side, 6 the other.

Re: Conditions 07/11

Posted: 08 Nov 2018 13:48
by tvdxrools
and as i have said before dont look for 20 over 9 sigs although you might if condits are good but flags dont work that way , they give a good s/n ratio and be happy with a s4 or 5 or weaker but you can hear the dx thats what your looking for , i know one dxer who stopped using a flag as he was expecting endstop sigs as he was used to hearing signals backed up with mush , i am happy with a s1 with a clear id , David

Re: Conditions 07/11

Posted: 08 Nov 2018 13:50
by satnipper
So it looks as though you have the beverage balun which I have on my Flag here. Mine works very well with it - had some good MF DX in the summer and it's working very well at the higher frequencies. I wouldn't mess with the unit as it is well sealed.

This is the link for the Flag kit if you want to get the Flag balun https://www.ebay.co.uk/itm/Flag-Pennant ... rk:15:pf:0

Each environment is different in practice - if you're getting the daytime 6070/6085/6150 coming in well (allowing for fading) and some long-ish distance daytime Irish or UK MF stations you'll probably be fine for when the NA MF DX rolls in again. I broke all the rules with my 10x2m Flag and it worked so well I'm reluctant to change anything!

Re: Conditions 07/11

Posted: 08 Nov 2018 13:51
by tvdxrools
if it aint broke John thats what i say ,, i always used 48/11 on a flag as it worked for me but like you you might find 18/6 works better ,David

Re: Conditions 07/11

Posted: 08 Nov 2018 13:52
by satnipper
18:6 turns ratio is a 9:1 impedance ratio - Peter gave the calculation.

Re: Conditions 07/11

Posted: 08 Nov 2018 13:53
by satnipper
48:11 turns ratio is 19:1 impedance ratio.

Re: Conditions 07/11

Posted: 08 Nov 2018 13:53
by John Faulkner, Skegness
That's true. Flags are not high gain antennas. The main reason I think they are popular is because of the band-wide nulls. The lower angle reception they possess is also hugely beneficial = more distant signals. A fact I did not believe until I swapped from loop to flag. Not once did I ever experience west coast North America in 20+ years of MW DXing. Then I switched to the ewe/flag. BOOM! There it was, as regularly as conditions allowed.

Re: Conditions 07/11

Posted: 08 Nov 2018 13:54
by John Faulkner, Skegness
This is where my technical knowledge (lack of) lets me down. Surely 18>6 is 3:1? I am confused.com

Re: Conditions 07/11

Posted: 08 Nov 2018 13:57
by satnipper
Some dxers use a pre-amp like Paul C in Troon but I am not a fan as I've said before about amplifying urban/suburban noise on MF. Might be worth trying one out here as the only real noise is the neighbours's electric fence clicking which the NB circuit in Perseus combats well and the Jaguar CR V4 seems to cancel out well as well.

Re: Conditions 07/11

Posted: 08 Nov 2018 13:58
by satnipper
JF - it's a square relationship. A short cut calculation is to divide the turns ratio and then multiply the result by itself.

i.e. 18/6 = 3. 3 x 3 = 9. So impedance ratio is 9:1

Re: Conditions 07/11

Posted: 08 Nov 2018 14:10
by tvdxrools
its not all set in stone , try out ones which will work on your flag , talking of Paul in troon the one i gave him didnt work to well on my flag but worked great on his

Re: Conditions 07/11

Posted: 08 Nov 2018 16:36
by John Faulkner, Skegness
OK. So it's not a figure ratio. Thanks.

Re: Conditions 07/11

Posted: 08 Nov 2018 19:03
by MarkdxAnglesey
That's how I do it John.
And for transmitting
So right

Re: Conditions 07/11

Posted: 08 Nov 2018 19:07
by John Faulkner, Skegness
Thanks. Shows you what I know :)

I DX. I don't *do* tech! Well, maybe a little. As long as it is simple.

Re: Conditions 07/11

Posted: 08 Nov 2018 19:10
by simbeav
Thanks for all the input. I'm going back to the loop for the time being as I clearly have an issue.

I am getting NO null and adjusting the resistor makes no difference.

Considering the conditions, the signals I was getting lower down the band were not bad, but higher up is useless (I possibly have a new noise source affecting the upper band, but I don't think that is the issue.)

The German 49m stations were coming in just, but nowhere near as good as on the loop

I'll look at adjusting the turnings on the balun

Thanks for all the help.

Re: Conditions 07/11

Posted: 09 Nov 2018 09:40
by satnipper
Very poor overnight again here. Yet 1548 Gold is S9 at 09.20 UTC.

Radio New Zealand is coming in well on 9765 kHz on the Flag at the moment

Stuart

Re: Conditions 07/11

Posted: 09 Nov 2018 10:18
by tvdxrools
I am getting NO null and adjusting the resistor makes no difference

it looks like for sure you have the wrong balun , conditions very average up here his morning just east coast usuals from 0700 - 0800 , the band died out abt 0815 , David

Re: Conditions 07/11

Posted: 09 Nov 2018 10:24
by John Faulkner, Skegness
Solar wind remains in 'orange' in Jaguar, indicating disturbed conditions. It looks like it isn't going to improve in a hurry either.

Traditionally, November (and February) are often the poorer months in the winter MW DXing calendar. I do not know why this is, but history shows that there are a smaller number of decent catches during these months. I would like to see this fact disproved, but my personal all-time log also backs this up.

Yep, conditions are sh*te here too, and generally lower signals across the band.