[Elecraft] Static rain ?
I have recently been plagued by rain static on a new vertical antenna, this is a 42 foot vertical fed at the base through an SG230 auto tuner, and used on all bands. It seems I need a static bleed of some sort, a choke or resistor. What is the best component to use in an outdoor environment? My junk box RF chokes look rather puny for this application, the typical small 2.5mH RF choke. Would a physically large, say 1 Meg resistor be more suitable ? I thought the auto ATU would in itself provide a static bleed path, but apparently not. Is the K2 prone to front end damage due to this static charge? I do not have the back to back diodes fitted (to prevent huge signal overload) Any thoughts, how have you solved this? 73, Deni F5VJC -- 73, Deni F5VJC ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
RE: [Elecraft] Static rain ?
Deni, I would be tempted to wind my own RF Choke. Use a large ferrite core (FT240-61 for instance) and wind as many turns of 20 guage wire on it as you can. Connect it from the vertical to ground and see if it works. Unless you have some unusual condition where the static noise is creating huge voltages at the antenna input, it is not likely to damage the receiver - the annoyance of listening to it is the baggest problem. This is noise pickup from static discharges at the antenna rather than a direct discharge of static into the receiver. The diodes in the T/R switch will offer some protection for the K2 receiver. 73, Don W3FPR -Original Message- I have recently been plagued by rain static on a new vertical antenna, this is a 42 foot vertical fed at the base through an SG230 auto tuner, and used on all bands. It seems I need a static bleed of some sort, a choke or resistor. What is the best component to use in an outdoor environment? My junk box RF chokes look rather puny for this application, the typical small 2.5mH RF choke. Would a physically large, say 1 Meg resistor be more suitable ? I thought the auto ATU would in itself provide a static bleed path, but apparently not. Is the K2 prone to front end damage due to this static charge? I do not have the back to back diodes fitted (to prevent huge signal overload) Any thoughts, how have you solved this? 73, Deni F5VJC -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.432 / Virus Database: 268.15.15/580 - Release Date: 12/8/2006 12:53 PM ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Static rain ?
Deni, My suggestion is that you use a resistor and not a choke. A choke at some frequencies will become a series resonant L-C 'tuned' circuit, and it is quite possible that the choke will resonate in or close to one of the bands that you use. If that is the case you will loose transmitter power heating up the choke, likewise the strength of received signals reaching the receiver can be reduced. For static bleeds I usually use 100k 2w carbon resistors, the old fashioned type not carbon film, because the resistors *must* be non-inductive types. My K2 survived a lightning strike to my 40m beam, but I think that the combination of a coax spark gap out in the garden and an underground coax feeder with 'surge loops' took out much of the sting. Back to back diodes for protection against overload can create all sorts of intermodulation problems if the diodes start to conduct, and for those of us in Europe who share 40m with BC stations and using receivers which cannot cope, overload is a problem but there are solutions. Please contact me off list if you are interested. 73, Geoff GM4ESD - Original Message - From: Deni [EMAIL PROTECTED] To: Elecraft@mailman.qth.net Sent: Saturday, December 09, 2006 9:52 AM Subject: [Elecraft] Static rain ? I have recently been plagued by rain static on a new vertical antenna, this is a 42 foot vertical fed at the base through an SG230 auto tuner, and used on all bands. It seems I need a static bleed of some sort, a choke or resistor. What is the best component to use in an outdoor environment? My junk box RF chokes look rather puny for this application, the typical small 2.5mH RF choke. Would a physically large, say 1 Meg resistor be more suitable ? I thought the auto ATU would in itself provide a static bleed path, but apparently not. Is the K2 prone to front end damage due to this static charge? I do not have the back to back diodes fitted (to prevent huge signal overload) Any thoughts, how have you solved this? 73, Deni F5VJC ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Static rain ?
Very interesting Geoff, thanks for the comments. I've deliberately not installed those front end diodes in my K2. As to the rain static, we've had very severe rainstorms in France as I believe you too have experienced in the UK and this problem with rain static I have never heard so bad, however this is a relatively new antenna installation for me. The vertical element is constructed from a 42' length of coax using the braid as the radiator to provide a fat wire, this radiator is suspended inside a Spiderbeam fiberglass pole so is in no way in direct contact with the rain. I used to use a butternut vertical (exposed aluminium vertical radiator) and didn't notice rain static quite like this. Yes my feeling is the resistor bleed would be better than the choke for the reasons you mention, still, I've just been out and measured the resistance from the antenna to ground and of course it reads zero Ohms, through the ATU I imagine so I don't quite see why I need a further static bleed path, but I'll try it anyway. Good to hear your K2 is a survivor, I've not had that horror, something I dread, however at the base of my antenna is a spark gap arrestor and then the auto ATU so...fingers crossed. 73, Deni F5VJC Geoffrey Mackenzie-Kennedy wrote: Deni, My suggestion is that you use a resistor and not a choke. A choke at some frequencies will become a series resonant L-C 'tuned' circuit, and it is quite possible that the choke will resonate in or close to one of the bands that you use. If that is the case you will loose transmitter power heating up the choke, likewise the strength of received signals reaching the receiver can be reduced. For static bleeds I usually use 100k 2w carbon resistors, the old fashioned type not carbon film, because the resistors *must* be non-inductive types. My K2 survived a lightning strike to my 40m beam, but I think that the combination of a coax spark gap out in the garden and an underground coax feeder with 'surge loops' took out much of the sting. Back to back diodes for protection against overload can create all sorts of intermodulation problems if the diodes start to conduct, and for those of us in Europe who share 40m with BC stations and using receivers which cannot cope, overload is a problem but there are solutions. Please contact me off list if you are interested. 73, Geoff GM4ESD - Original Message - From: Deni [EMAIL PROTECTED] To: Elecraft@mailman.qth.net Sent: Saturday, December 09, 2006 9:52 AM Subject: [Elecraft] Static rain ? I have recently been plagued by rain static on a new vertical antenna, this is a 42 foot vertical fed at the base through an SG230 auto tuner, and used on all bands. It seems I need a static bleed of some sort, a choke or resistor. What is the best component to use in an outdoor environment? My junk box RF chokes look rather puny for this application, the typical small 2.5mH RF choke. Would a physically large, say 1 Meg resistor be more suitable ? I thought the auto ATU would in itself provide a static bleed path, but apparently not. Is the K2 prone to front end damage due to this static charge? I do not have the back to back diodes fitted (to prevent huge signal overload) Any thoughts, how have you solved this? 73, Deni F5VJC ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
