:), will see how it ends. I've been there in that house with my airBalticcard and a N5000 and a N8310, there is definitely no signal. 20m outside you get a weak signal from i.e. Vodafone.

I was also thinking about another mobile and an external antenna to plug in, but I don't have any experience with this. Which mobile? Which antenna? That's the reason why I wanted to go for callback......

In that case, it is worth making use of that landline resource if she has it. Enlinea and Call Back World are a bit useless these days I think. A few months ago there was a post here* about a new UK based callback provider. Their rates were good. I suspected that they used Betamax even though they were not themselves Betamax. I think the trigger was some nice easy to remember UK number like 0044 123456.... I cannot find the post now but a bit of looking around will probably bring it up. Maybe it is worth a trial of putting 10 pounds on or something.

* It might have been on foneforum.co.uk. I do not remember. I remember the company as they also claimed to have an access number for India that they refused to publish on their website. There was some discussion about that.

I fianlly tracked those down! The ones that were talked about were Nyxfone.com and talkbacktele.com. I have not tried either personally, but I think the first had very decent rates.

Checkout this link: Cell phone signal, Mobile Booster, Mobile Phone Booster, authorised dealer distributor new delhi, deepak javherani, General Electronics & Telecommunications

I guess when you search google there must be other units like this. Cellphone booster.

Thanks a lot ! That could be another interesting solution.
Does anybody have experience with this?

Are they legal in Spain?

Thanks Petkow, that Nyxfone looks great! Until now this seems to be the best solution. :):):)

Nyxfone problems
 

I created a Nyxfone account and made some attempts.
Too many failed. Balance check and SMS sending ("Account is not actíve") does not work.
Customer service answered quickly, but was not helpful.
They just ignored the problems with balance and SMS.

Any other suggestions with similar rates????

Sorry to hear that! I presume you have also looked at the two USA based callback "dinosaurs":
Enlinea International Telephone Calling Overseas Dial Direct Discount - international callback,direct dial,international long distance,toll-free forwarding, local newspapers, local weather, dictionary, translator calling card and VoIP services
Callback World - callback service for country to country calling

By the way, I know it sounds obvious but do you have any idea if she can call Spanish 900 (freephone) numbers? If so an account based service maybe a good option.

Also I think it was asked before but there are loads of gateways (even to UK mobiles) using special 901 and 902 numbers. As the rates to call these are supposed to be fixed (by Spanish law AFIK) they maybe cheaper than what she is paying for standard rates.

I suspect Nyxfone fails due to unreliable outbound CID generated by the local carrier.

Both CallbackWorld and Enlinea provide dedicated trigger number based callback which is not affected by missing or invalid oubound CID.

On second thought, you may want to give StanaCard a try. They assign a Madrid proper (landline) number to each of your international destinations.