AirNav Systems Forum
AirNav RadarBox and RadarBox24.com => AirNav RadarBox and RadarBox24.com Discussion => Topic started by: Deadcalm on September 13, 2008, 02:33:17 PM
-
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
-
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.
-
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
-
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
-
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
-
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
-
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
-
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
-
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
-
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
-
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
-
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=-
-
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
-
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
-
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
-
Hi DC,
My Kuhne preamp has been operating continuously since 24/10/2005 and survived many local thunderstorms. I additionally use a SSE 1090SJ mk2 antenna which is DC grounded. A recent inspection showed the preamp to be in an "as new" condition. Contact Jana Munzert at Kuhne for details.
http://www.polarorbiter.co.uk/Graphics/Kuhne.gif (http://www.polarorbiter.co.uk/Graphics/Kuhne.gif)
Cheers
-
Great stuff - thanks, Cumulus. I've written to Kuhne with a view to ordering.
DC
-
"Cumulus" do you read ???:
appreciate you did Cumulus !!!
Karl
-
Cumulus, I se that the SSE 1090SJ mk2 antenna has only 2 dB gain, but the Wimo allegedly has 5 dB. Has anyone ever compared the two like for like in terms of performance?
DC
-
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
Hi,
to which address did you send a mail to WiMo and when? I have not received anything over the weekend.
Rgds,
Ekki/WiMo
-
Hello EKKi at Wimo, thanks for your input.
I sent the following E mail to Support@Wimo on 13th September, at 15:58:
______________________________________________
"Hello
I purchased a Wimo antenna, cable, Bias Tee and Preamp for my Airnav RadarBox.
(14th February, Wimo Order 080214040)
One or other of the components seems now not to be operating correctly.
Until now, the range of acquisition of targets for my RadarBox has been around 250 nm, and I've been very pleased.
Suddenly, the range has dropped to less than 100 nm. I have checked all the connections (which were all sealed with self-amalgamating tape) and all seem dry and clean. I have tried the RadarBox with the magnetic antenna supplied by Airnav, and that works OK - better than the current results with the Wimo. Is it likely that one of the Wimo components has failed?
Can you advise the best course of action, please? Are these units under guarantee?
Regards
(My Name)"
__________________________________________
Hope no-one minds me adding the text here.
Regards
DC
-
Did you get that, Wimo? No reply from you here or by E Mail as yet...
But I have had a reply from Kuhne.
DC
-
Yes, got it now (I only check this forum once a day, if at all). I will reply by mail.
Rgds,
Ekki/WiMo
-
Cumulus, I se that the SSE 1090SJ mk2 antenna has only 2 dB gain, but the Wimo allegedly has 5 dB. Has anyone ever compared the two like for like in terms of performance?
Deadcalm, don’t care too much about 2 or 3 db of “antenna gain”. There is al lot of “believing” in those figures. The “dbs” are refernced to what is called an isotropic (punctiform / ball like / ideal) radiator, uniformly radiating its transmission energy into ALL directions, whilst “real” antennas all develop different kinds of directional behavior, thus “concentrating” their energy into this direction(s). The above applies for transmitting antennas, but vice versa for receiving antennas as well.
And, by the way: as you are going to use a preampp, this one really will give you a lot of “dbs” by its amplification, even if some of them are “eaten up” again by your 18 meters of coaxial cable. (~ 3 db @ 20 meters of ECOFFLEX 10)
Cumulus of course is doing great by operating a “DC grounded antenna” as you might have read. Such antennas using a small inductive element at their “feeding point”. The inductance almost does not have influence on the RF signal travelling to the receiver, (ANRB) but shortens possible Electrostatic Charges to ground, thus preventing the receiver to beeing hit by "ESD".
Kind regards
Karl.
-
Thanks for the info, Karl. Wimo have asked me to send the preamp to them - they'll check it and see if it needs repair. Don't know if it'll be a warranty job, though. In the meantime I've ordered a new preamp from Kuhne, so I should be up and running by the end of the week. And if the Wimo preamp is faulty and can be repaired, I'll have a spare!
So what would I additionally need to have a "DC grounded" antenna?
DC
-
So what would I additionally need to have a "DC grounded" antenna?
Hi Deadcalm,
it is the antennas design, that makes it a "DC grounded" antenna. As Cumulus mentions in this thread before:
My Kuhne preamp has been operating continuously since 24/10/2005 and survived many local thunderstorms. I additionally use a SSE 1090SJ mk2 antenna which is DC grounded. A recent inspection showed the preamp to be in an "as new" condition. Contact Jana Munzert at Kuhne for details.
he uses this type of antenna, (in conjunction with the also mentioned amplifier) obviously without any problems. Looks good.
If you were able to do some mechanical "tinkering" and soldering, (or if you've got a friend to do so, may be even a radioamateur) I could offer you some hints on building a small device to be put between the antenna (end of coax cable) and your receivers input, thus having the same effect as has an antennas "DC grounding".
In case of interest just let me know via e-mail. AirNav does not like the nickname of of the "black box" above. Believe it or not...........
Regards
Karl
Added:
check this link for a "DC grounded antenna: http://www.ssejim.co.uk/26-sseads1090sj.htm
and notice:
To greatly reduce noise caused by atmospheric discharges-lightening, etc., all metal parts are DC - Grounded with the antenna showing a DC - Short Across the "N"Coaxial Socket. This also greatly reduces problems with RF-Pre-amp, Input Stages
K.
-
Thanks for the info, Karl. I have looked at the SSE Jim antenna already, and I'm considering it. I didn't really want to have to buy another antenna, but if I end up with a spare preamp, a second aerial could be useful for an alternative location.
DC
-
Hi all, not got an RB yet, but have negotiated one a Christmas pressie from my better half, who can't see why on earth I want to get one! I do a lot of SW Listening on various receivers. With all electrical connections out of doors, I lag connectors (and try to get some inside co-ax, after soldering) with electricians' silicone grease, which is available for around £3.50 per 50g tube, water and damp hate it - I've never had any problems with corrosion. Water can get into co-ax and will actually move through it by gravity and capillary action. In preference to self-amalgamating rubber tape, which will deteriorate, perish and crack, I try to use cable gland covers which can have silicone grease put in before fastening with wire tie at the wide end, you just cut off the blind end to get a slightly small diameter than the outer of the co-ax you're using. It used to be possible to buy purpose made lightning arresters with double-ended SO239 fitting, which had a very small spark gap (about 0.001 inch) from the internal conductor the outer body which had a heavy cable to earth - electricity, being extremely lazy like me, will take the shortest and easiest route to earth. Even with these fitted, it is good practice to disconnect outside antennas from the back of the boxes, and ideally earthed.
Thanks to all those who posted replies and PMs to me, when I inquired SBS-1 or AirNav RadarBox on the Kinetic site, before the post was locked. This protectionist attitude has swayed me from the SBS-1 route (which I had more or less decided to go with) and the helpful attitude and advice from RB users (some of whom have feet in both camps) and watching what goes on in this Forum. Hopefully, I'll be able to make some useful input in here.
-
Welcome CoastGuardJon.
You won't get your post locked here if you compare products, why? because we know RB comes out top :)
-
Welcome CoastGuardJon.
You won't get your post locked here if you compare products, why? because we know RB comes out top :)
Thanks for the welcome. I was pointed to your detailed camparison document by another Forum member, and while I don't swallow it 100% - it is a very good sales pitch though! - at least you're open minded, and I have seen criticisms in here which then been taken on board and addressed. I don't expect total perfection and satisfaction from any supplier (not just in this sort of equipment, but right across the board), but at least you allow resonably free discussion, for which I thank you - having done the brown-nosing, I don't suppose you have the odd spare unit around, I could borrow and review..............?
-
Hi CoastGuardJon, glad you were able to make the "right" decision. Looking forward to the coverage from Cornwall on the network.
Have you ever thought of using ShipPlotter, you're probably in a good location for shipping as well.
-
Or better wait for AirNav ShipTrax, you will be amazed with what it does. Check www.airnavsystems.com/shiptrax
-
hi dc
dont no if you still moitor this thread but have just had mye new amp fail again only a few weeks old same as last ime checked all connection for water ingress etc found none have cotacted kuhne for pricing of there kit this time suspect static dont know how as fully earthed and bonded but hey thats my luck again
-
I now have the new Kuhne preamp up and running - seems OK at the moment.
The failed one was from Wimo. I sent it back last week for them to look at and repair if necessary (hopefully under warranty). They promised to let me know when it arrived, but I've heard nothing yet...
DC
-
I just wonder whether the failure of Wimo pre-amps are anything to do with the fact that they don't supply a 12 power adaptor. Maybe people are using 12v supplies that aren't suitable for the Wimo pre-amp?
It's one thing I was concerned about when I received my Wimo pre-amp. No 12v supply, and all instructions in German. I just hope the 12v adaptor I'm using is suitable.
-
Kuhne didn't supply a power adaptor, either. I suppose if you are aware of your PSU output specs, and they fall within the requirements of any preamp, then you should be OK.
I'm using the same PSU as I did for the Wimo, and the Wimo Bias Tee as well...
DC
-
Well, I had two 12v adaptors available. I checked the first, and despite being labelled as 12v, it was outputing 17v !!! The second one output 12v, so that's the one I'm using.
I just wonder if I had used the first adaptor whether that may have then caused a failure.
The Wimo instructions only specify 12v at 100mA. That's assuming Spannungsversorgung means voltage, and Stromaufnahme means current.
-
The Kuhne Bias T (which I'm not using at the moment due to lack of N connectors) accepts a voltage range up to +15v DC, max. 1 amp.
DC
-
The Wimo instructions only specify 12v at 100mA. That's assuming Spannungsversorgung means voltage, and Stromaufnahme means current.
Right tarbat
and don't care too much about the bias supplies. The 17VDC you've been measuring is the "idle voltage" (no load connected to the supplies output), that will settle at about 12VDC "nominal voltage", as soon as the amplifier draws current (load connected) via the "Tee". The operating voltage though may not be 12VDC exactly, but the amplifier can "live with it", if it remains within certain limits. (you might take another voltage measurement with the amplifier then connected) No need to use a "stabilized" power supply, which of course will deliver its rated voltage within a small margin. (even if there is no load connected to it)
Regards
Karl
-
Right tarbat
and don't care too much about the bias supplies. The 17VDC you've measured is the "idling voltage" (no load connected to the supplies output), and it will settle at about 12VDC as soon as the amplifier draws current (load connected) via the "Tee". The operating voltage though may not be 12VDC exactly, but the amplifuer can live with that if it remains within certain limits. No need to use a "stabilized" power supply, which of course will deliver its rated voltage within a small margin. (even if there is no load connected to it)
Regards
Karl
Spot on Karl, the PSU needs to be able to supply a minimum of 100mA at 12V to work satisfactorily, but some of the PSUs around (eg those provided with re-chargeable handlamps) are not of the best quality and could well do with some modification before being used with this sort of application.