Not my weekend!

[Deadcalm]

I've discovered that my Wimo pre-amplified antenna no longer seems to work properly.
Coverage usually extends to about 200+ nm easily, but has dropped to around 100 nm.
Disconnecting the Bias T power supply reduces coverage to about 40 nm, so it's still doing something. Replacing the antenna feed with the Airnav supplied one now gives better coverage.
All the connections seem to be OK up to the antenna.
Has this happened before to anyone?
Woe is me!!  (Flightchecker, have you any ideas, Karl?)

DC

[AirNav Support]

Check the connections if you can get to where the antenna is. Sometimes due to rain and humidity there could be rust of general build up around the connectors.

You are usually advised to use weather proofed tape to cover them up.

[Deadcalm]

The connections are fine, and they were all properly sealed with self-amalgamating tape.

Do Bias Tees and/or preamps fail?  (Less than a year old)

DC

[pcochrane12]

deadcalm
just had the same happen to me and ended up ordering a new pre-amp also less than a year old all joints where sealed in self amalgimating tape and then rapped in denzo water proof piping tape
cheers paul

[flightchecker]

Hi DC,

looks like Paul is "telling the truth". Following your "fault description" as well as your "trial and error measures", it's the preamplifier that remains to be the  cause of your trouble.

Do Bias Tees and/or preamps fail?  (Less than a year old)

Preamps yes, Bias tees most unlikely not. (just a few and "passive only" components as compared to the "active" and passive components as applied in a preamp)
Give the antenna a try to operate without the preamp when the latter may be sent to WiMo for repair. Maybe results are not too bad, if the coax does not extend too much.
If you remove bias from the amplifier, it will act as an attenuator, so degrading reception more or less.
Hope you took at least part of the measures that Paul has undertaken to prevent water and / or humidity to enter the preamp. A MUST !

will post results of fault investigation as and when i get round to it

Hi Paul, Yes please !!!

(Edited)

Karl
Kind regards

[pcochrane12]

hi karl
yep totally agree havent got round to repairing the amp yet but will post results of fault investigation as and when i get round to it
cheers paul

[Deadcalm]

Well, that's a big disappointment for a Wimo product.  Shame, because I thought the gear was highly thought of.

I have sent an E Mail to Wimo, in the hope that there may be some guarantee for the products - the whole shebang cost in excess of 1000 Euros.

I can't find the A12-1090 preamp as a separate item on the Wimo website, which doesn't bode well...

If they won't replace it, I may consider an alternative - any recommendations?

Until then that's me effectively off line.

Karl, I can't run without preamp/Bias Tee because I don't have any spare N/BNC plugs or adaptors to hand, and the antenna is at full stretch height-wise, with no coaxial play left.

#Update - it seems this is a common preamp available everywhere, price around £200 (inc BT-12)!  If one of these fails every year, and subscribing to the Airnav network costs £60, it's going to become an expensive hobby for a poor retired old git like me!

DC

[pcochrane12]

yep deadcalm mines only been up since march/april time its now cost me 150quid for a new one going to try and repair the old one but if no success and the system fails again i wont be replacing the amp but will look for an alternative system.very dissapointed with the failure considering the reputation wimo gear has but hey thats just my luck
cheers paul

[Deadcalm]

No guarantee, then, Paul?

I'll see what Wimo say, if they reply.  I think I'll also drop an E Mail to Elad, the manufacturers and see what they say.

DC

[flightchecker]

If they won't replace it, I may consider an alternative - any recommendations?

Wonder if you really need one at all deadcalm. What's the lenght of the coax from the antenna to the RB ?

Karl


Added:

paul and deadcalm
won't start a new discussion about E lectro S tatic D ischarge, as I might run into trouble with
WiMo as I did with AirNav before. Nevertheless ESD could be a good reason for a preamp to degrade in performance if not even fail totally, as well as could the frontend of ANY receiver (not just SBS-1 or RB ;) that is UNPROTECTED against this phenomenon.

It's up to WiMo to follow up this possibility.

Karl

[pcochrane12]

hi dc
dont know about the guarantee so much as the not having an active system will look into that now the system is up and running again
cheers paul

[GlynH]

If they won't replace it, I may consider an alternative - any recommendations?

Sorry to hear of your problems DC...I will be getting the Kuhne Pre-Amp & Bias Tee soon not to boost my signal as I see enough generally but as protection against ESD.

I believe Kuhne are regarded as the Rolls Royce when it comes to LNA and the like.

http://www.kuhne-electronic.de/en/shop/143_Vorverstaerker/article:342_KU_LNA_1090_A_TM

Last prices I had were as follows;

1 x       MKU LNA 1090 A TM   163,00 €
1 x       KU BT 271 N                47,00 €

Shipment to Great Britain         14,50 €

All prices are within German VAT.

As a power supply you would need the following specifications:

Output voltage: + 12 V, regulated
Output current: min. 200 mA
Connector type: DC plug (2.1mm)

Hope that helps...

Good luck!

Kind regards,
-=Glyn=-

[Deadcalm]

Karl, I have (of necessity) a horizontal coax run of 18 metres, plus a vertical run of about 3 metres, so I think a preamp is required, ideally.

Glyn, thanks for the Kuhne information - that may well be worth looking at as an alternative.  From what you are saying, does this provide ESD protection where the failed one probably didn't?  If I go for your suggested combination, somehow I'll have to also find either an SMA/N patch lead, or a BNC/N converter in the wilds of France! (Unless, of course, I can use the existing Bias Tee).

DC

[flightchecker]

Karl, I have (of necessity) a horizontal coax run of 18 metres, plus a vertical run of about 3 metres, so I think a preamp is required, ideally.

YES no doubt !!!

"Cumulus" do you read ???:

May I please encourage you to tell deadcalm about your (excellent) experience with the "Kuhne" that it is about above ? (We've been corresponding on that)

Deadcalm is your antenne pole "grounded" by some means ? I've been asking this permanently before, as it is considered to be a first  measure (several others of course) of ESD protection.

The adapters your talking about are "standards" and should not create a problem to purchase.
If possible, also take care to attach some kind of "flexible" "pigtail"(cable) between the (probably !?) thick and "stiff" end of the coax that is  running down from your antenna. Otherwise the SMA input connector might break at it soldering posts on the component board.

No problem with the existing Bias Tee, as far as you are able to supply the suitable voltage as requested by the amplifier to the Tee's DC input port. 

Karl

[Deadcalm]

Thanks, Karl, I'll purchase the necessary adaptor(s) on line.  And no, the pole isn't specifically grounded - but it can be if I put my mind to it!  I take it just a single lead to an earth rod will suffice...

DC