Re: LF: EA5DOM going vertical

[VIGILANT Luis Fernández <luis@vigilant.es>]

Hi Stefan

Yes. I have already doubled the voltage rate of the output filter. It was the second thing that

failed when transmitting with the loop. Output ferrite transformer is also cooled with fan and

small aluminium heatshink. Temptation to keep transmitting is too strong ! ;-)

Fortunately, even severy mismatched, the vertical is stable as a rock. The loop need continous

watching because capacitors heat and mismatch drifts from on Tx to the next one. A real hell !

It is just what you predicted  :-) 

Of course I need help from you all to match the PA. I have finished the coil this afternoon

120 turns of 0.9mm enameled copper over 25cm composite pipe. The plan is not to use taps

but use a ferrite transformer with taps to match. I have also an small variometer which can be

added

I wonder if the 490pF vacuum variable capacitor can be of use at any point in the matching

Hope to get it installed soon

73 de Luis

EA5DOM

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De: owner-rsgb_lf_group@blacksheep.org [owner-rsgb_lf_group@blacksheep.org] en nombre de DK7FC [selberdenken@posteo.de]
Enviado: sábado, 17 de octubre de 2015 17:53
Para: rsgb_lf_group@blacksheep.org
Asunto: Re: LF: EA5DOM going vertical

Hi Luis,

Be careful with running a mismatched PA. It may not blow up the FETs but maybe a C in the output filter. And the filter will not work very well too.
I guess you know how to match the antenna to the PA. Or do you need some advice and suggestions?
159V is nothing, it could be 20 dB more, easily. So i'm looking forward to your loaded antenna :-)

73, Stefan

Am 17.10.2015 16:33, schrieb VIGILANT Luis Fernández:

Thank you Stefan :-)

This is being posible with the help of many friends found here in the reflector, like you

This morning I have added the loop to the ground side of the vertical (dipole). No difference

in the loading. Still mismatched. The PA rms out is 159V and input power 9A@12V

That should be 62V rms over a 50Ohm load. Anyway much better and less stressing

working conditions that a high Q loop and can run WSPRS every 8 minutes without problems

For the QRSS-3 QSO can be tomorrow sunday evening. Today I'll be out and just running WSPR

What a coincidence ! It will also be my first QSO with DL on this band. In fact, will be my first QSO

in this band ! :)

No pictures about the arrangement because there is no arrangement. Just the vertical antenna

The radial go down inside the building trought a ventilation pipe. Let's see tonight if the loop around

the base of the vertical antenna makes some difference and can reach LA ! 

73 de Luis

EA5DOM

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De: owner-rsgb_lf_group@blacksheep.org [owner-rsgb_lf_group@blacksheep.org] en nombre de DK7FC [selberdenken@posteo.de]
Enviado: sábado, 17 de octubre de 2015 12:00
Para: rsgb_lf_group@blacksheep.org
Asunto: Re: LF: EA5DOM going vertical

Hi Luis,

My congrats!!!
This is a very good result for an unloaded 10m vertical antenna!
The coil will make a big difference, a few 10 dB i expect, although this is hard to imagine since your reports are very good already.

Do you like to try a QRSS-3 (or DFCW) QSO? :-) Would be my first on that band to EA.

73, Stefan

PS: Show us some photos of the new arrangement.

19 spots:

Timestamp	Call	MHz	SNR	Drift	Grid	Pwr	Reporter	RGrid	km	az
2015-10-16 23:40	EA5DOM	0.475791	-30	0	IM98wn	0.05	DG3LV	JO53gv	1887	22
2015-10-17 01:56	EA5DOM	0.475789	-29	0	IM98wn	0.05	PI4THT	JO32kf	1613	17
2015-10-16 20:24	EA5DOM	0.475790	-25	0	IM98wn	0.05	DH5RAE	JN68qv	1576	39
2015-10-17 00:24	EA5DOM	0.475788	-29	0	IM98wn	0.05	DJ0ABR	JN68nt	1556	39
2015-10-16 23:40	EA5DOM	0.475789	-29	0	IM98wn	0.05	DF6MK	JN68ik	1505	39
2015-10-16 20:40	EA5DOM	0.475789	-28	0	IM98wn	0.05	PA0RDT	JO11tm	1470	10
2015-10-17 03:32	EA5DOM	0.475790	-24	0	IM98wn	0.05	G8HUH	IO81mg	1430	352
2015-10-17 01:56	EA5DOM	0.475789	-33	0	IM98wn	0.05	G3XKR	IO70ux	1419	348
2015-10-17 00:08	EA5DOM	0.475791	-20	0	IM98wn	0.05	DK7FC/P	JN49ik	1398	27
2015-10-17 00:32	EA5DOM	0.475791	-30	0	IM98wn	0.05	DK7FC	JN49ik	1398	27
2015-10-16 23:24	EA5DOM	0.475789	-28	0	IM98wn	0.05	DL6RCN	JN58kg	1395	36
2015-10-17 02:00	EA5DOM	0.475789	-25	0	IM98wn	0.05	F6CNI	JN19qb	1200	12
2015-10-17 04:48	EA5DOM	0.475790	-29	0	IM98wn	0.05	F4HBT	JN08qx	1164	5
2015-10-16 22:32	EA5DOM	0.475789	-30	0	IM98wn	0.05	F6GEX	IN97na	942	357
2015-10-17 02:56	EA5DOM	0.475791	-29	0	IM98wn	0.05	F1AFJ	JN06ht	919	4
2015-10-17 02:00	EA5DOM	0.475789	-29	0	IM98wn	0.05	F5OZF	IN94su	700	358
2015-10-17 03:24	EA5DOM	0.475792	-18	0	IM98wn	0.05	EA2HB	IN93ah	550	344
2015-10-17 00:00	EA5DOM	0.475789	-25	0	IM98wn	0.05	EB3FRN	JN01mc	300	19
2015-10-17 05:48	EA5DOM	0.475789	+4	0	IM98wn	0.05	EA5DOM-1	IM98xn	7	90

Am 17.10.2015 00:28, schrieb VIGILANT Luis Fernández:

New experiment ongoing tonight :-)

Just the 10,25m vertical with one vertical radial about 11m long hanging down

A vertical dipole, really

No coil, no adaptation. Have used this with the bare U3 and thought it would not be

possible to use the PA due to mismatch. But tried .... and it is not so bad :-O

Reports from EU stations show that the vertical radiates much better Dx signal

than the horizontal loop, even counting on the crude feeding system used

We all knew that. Just a confirmation ;-)

Working in the coil this weekend

Keep tuned 

73 de Luis

EA5DOM