Re: Topband: Common Mode Chokes
On 6/9/2013 6:57 PM, wb6r...@mac.com wrote: G3TXQ shows characteristics for common mode chokes There's lots of measured data in the RFI tutorial on my website. A 16 turn (x2) bifilar choke connected as parallel wire line will work VERY well on 160-40M. It will handle legal limit if the common mode voltage is fairly low at the point it is inserted. That is, if the antenna is reasonably well balanced. http://k9yc.com/RFI-Ham.pdf 73, Jim K9YC All good topband ops know how to put up a beverage at night. _ Topband Reflector
Re: Topband: Common Mode Chokes
I have built several chokes on FT240-31 cores with RG142 double silver shield TFE coax (ok for QRO anywhere at HF) and measured them with my VNWA 2.6. For my 160m top loaded vertical I stacked three cores and used 12 turns for >4k ohms resistive. My results generally agree with G3TXQ's and K9YC's charts, although I tend to use a few less turns than G3TXQ and more ferrite per K9YC to stay further away from the self resonance frequency. Keeping the windings tight was important. The big type 31 "clamp ons" are also pretty handy for cables in place or with PL259's installed. Grant KZ1W On 6/9/2013 6:57 PM, wb6r...@mac.com wrote: G3TXQ shows characteristics for common mode chokes: http://www.karinya.net/g3txq/chokes/ Has anyone built the 17T of RG58 on an FT240-31 choke and verified the performance? TU - Steve WB6RSE All good topband ops know how to put up a beverage at night. _ Topband Reflector All good topband ops know how to put up a beverage at night. _ Topband Reflector
Re: Topband: Common Mode Chokes
Jim, K9YC, where are you ? (If anyone has Jim has for sure) Bob K6UJ On Jun 9, 2013, at 6:57 PM, wb6r...@mac.com wrote: > G3TXQ shows characteristics for common mode chokes: > > http://www.karinya.net/g3txq/chokes/ > > Has anyone built the 17T of RG58 on an FT240-31 choke and verified the > performance? > > TU - Steve WB6RSE > All good topband ops know how to put up a beverage at night. > _ > Topband Reflector All good topband ops know how to put up a beverage at night. _ Topband Reflector
Topband: Common Mode Chokes
G3TXQ shows characteristics for common mode chokes: http://www.karinya.net/g3txq/chokes/ Has anyone built the 17T of RG58 on an FT240-31 choke and verified the performance? TU - Steve WB6RSE All good topband ops know how to put up a beverage at night. _ Topband Reflector
Re: Topband: Stew Perry 160 meter contest
Please lets send reminders for this contest next weekend.If I remember it I will play with a loading coil to get my 1/4 wave 80m vertical resonant on the top band. ~73 Don KD8NNU -.- -.. ---.. -. -. ..- -Original Message- From: Mike Waters Sent: Monday, June 03, 2013 2:18 PM To: topband Subject: Re: Topband: Stew Perry 160 meter contest And so far, no one here has mentioned the Summer Stew, either. And it's approaching fast! :-) The XYL (KD0LAJ) and I are going to spend part of our 37th wedding anniversary weekend having fun there (she's the logger). See you in the contest. :-) 73, Mike www.w0btu.com On Mon, Jun 3, 2013 at 1:05 PM, Mike Waters wrote: ... a significant 160 meter contest is missing there. ... All good topband ops know how to put up a beverage at night. _ Topband Reflector All good topband ops know how to put up a beverage at night. _ Topband Reflector
Topband: COMTEK CONTROLLER
Can someone please advise me on the correct method of setting up a pair of verticals to be used with the Comtek phasing controller? I have heard two methods: (1) tune each vertical without the controller to approximately 25 khz below desired frequency with the second vertical disconnected (2) tune each vertical to approximately 25 khz below desired frequency with the vertical to be tuned connected to the controller, the second vertical disconnected and the analyzer fed through a random length of coax long enough to reach either vertical element. I recently acquired one of these units to try. I have a perfectly good working homebrew phasing controller with a good working phased pair, but I am a cat and curiosity has got the better of me! When I try method #1 I can get the SWR in either endfire position down to about 1.5:1 with broadside position at about 1.7:1. Using the second method I get about 1.2:1 end fire but 2.5:1 broadside. Also, using the second method my verticals, which were resonant at around 1805 when checked directly at the base of the antenna turn out to be resonant over 100 khz higher when measured through the Comtek box, and I needed to add some length to get the SWR down to acceptable levels. Anyone got some insight on this? Bill, VE3NH - No virus found in this message. Checked by AVG - www.avg.com Version: 2013.0.3343 / Virus Database: 3199/6396 - Release Date: 06/09/13 All good topband ops know how to put up a beverage at night. _ Topband Reflector
