Re: Topband: Common mode choking of beverages

Hi Jim, I made a few of the RX chokes from your Chokes and Isolation Transformers for Receiving Antennas paper using CAT5 twisted pair. Why is it that these RX chokes are OK with twisted wires while the TX chokes described in A New Choke Cookbook for the 160-10m Bands admonishes that the paired

Re: Topband: Common mode choking of beverages

Mike, Would you be able to describe your choking method on the CAT cables? I'm using something related to your method, but am very interested in your successes. Thanks in advance, Rick Kunath, K9AO _ Searchable Archives: http://www.contesting.com/_topband - Topband

Re: Topband: Common mode choking of beverages

CAT5/6/7 cables consist of four 100 ohm twisted pairs, each with a different twist ratio to minimize crosstalk between the pairs. Indeed, there is nothing inferior about it as a feedline as compared to coax, except that it may see its Zo modified slightly if it's laying on the ground or very

Re: Topband: Common mode choking of beverages

I've seen Cat 5 and 6 cable used up to 20MHz on one pair, power on another and data on a third, perhaps switching on a fourth pair. I know this >works for distances of at least 20 metres and I wonder if it would be good at LF for 10 times that distance. It's also very tough and modestly

Re: Topband: Common mode choking of beverages - which side of grounded shack entry panel?

On 10/3/2020 11:24 PM, donov...@erols.com wrote: Double shielded coaxial cable or hard line coax with properly installed high quality coaxial connectors greatly minimize the penetration of common mode signals into the coaxial cable and the equipment to which it is connected. GM Frank, Quite

Re: Topband: Common mode choking of beverages - which side of grounded shack entry panel?

I've seen Cat 5 and 6 cable used up to 20MHz on one pair, power on another and data on a third, perhaps switching on a fourth pair. I know this works for distances of at least 20 metres and I wonder if it would be good at LF for 10 times that distance. It's also very tough and modestly priced

Re: Topband: Common mode choking of beverages - which side of grounded shack entry panel?

My DX Eng 4 sq (12v over RG6 to preamps) has had infuriating random arc noise for years and the W3LPL explanation makes great sense to me as the reason. I did silicone grease the F threads but followed the "CW advice" to not flood the connector so I have a project to do that. Hi-Z had a

Re: Topband: Common mode choking of beverages - which side of grounded shack entry panel?

W3LPL said "A peripherally related issue: Running DC power through the same coax cable as low level RF signals is asking for trouble." I agree completely. Here is my story of trying this. Maybe this will help if anyone has the same problem. I did this with one low signal level receiving

Re: Topband: Common mode choking of beverages - which side of grounded shack entry panel?

n2qt" To: donov...@erols.com Cc: topband@contesting.com Sent: Sunday, October 4, 2020 8:18:20 PM Subject: Re: Topband: Common mode choking of beverages - which side of grounded shack entry panel? I’ve heard that on low signal strength receive arrays, having multiple ground

Re: Topband: Common mode choking of beverages - which side of grounded shack entry panel?

y, October 4, 2020 5:24:05 AM Subject: Topband: Common mode choking of beverages - which side of grounded shack entry panel? Sorry if this has been asked and answered previously, but I don’t find it in a check of the archives. I’ll soon have an aluminum entry panel in my shack for all e

Topband: Common mode choking of beverages - which side of grounded shack entry panel?

Sorry if this has been asked and answered previously, but I don’t find it in a check of the archives. I’ll soon have an aluminum entry panel in my shack for all entering TX and RX lines (as well as rotator lines and misc control cables). The panel is copper-strapped to ground rods fifteen feet

Re: Topband: Common Mode

antenna feedlines (and > sometimes one in the middle), and it makes a very clear difference. > > Regards, > Art Delibert, KB3FJO > > > > From: Topband on behalf of Rodman, David > > Sent: Tuesday, October 23, 2018 6:41 AM > To: topband@contesting.

Re: Topband: Common Mode

(and sometimes one in the middle), and it makes a very clear difference. Regards, Art Delibert, KB3FJO From: Topband on behalf of Rodman, David Sent: Tuesday, October 23, 2018 6:41 AM To: topband@contesting.com Subject: Topband: Common Mode I purchased some

Topband: Common Mode

I purchased some 7mm dia snap on cores for RG6 receive antenna coax. I was wondering if anyone had any experience or suggestion as to how many one would place on each lead. The feed lines are about 50% on the ground with grass growing over or buried 2-3". The lengths vary from 300' to 750',

Re: Topband: Common mode choke 160m inverted L

Hi All, Thanks for the very useful info on chokes. After reading all this , i decided to build a choke with the same 10mm RG393 teflon silver wired coax. In Friedrichshafen i bought some beautiful spinner silvered 7/16 connectors for 10mm cable  :-) I used a longer piece and made 7 turns

Re: Topband: Common mode choke 160m inverted L

From: "ON4GPE" <on4...@gmail.com> To: donov...@starpower.net Sent: Saturday, December 23, 2017 7:06:48 PM Subject: Re: Topband: Common mode choke 160m inverted L Hi Frank, Yes only two 1/4 wave elevated radials (3 meter high), it's not possible to use ground radials. 73

Re: Topband: Common mode choke 160m inverted L

Hi Gert, What you are suggesting, *** at 1.8 MHz ***, even with 34 of those cores on a 1 meter length coax would have only a few hundred ohms blocking, not nearly enough blocking to do anything serious. It might somewhat knock down back-feed of noise from the house running out to the antenna, but

Topband: Common mode choke 160m inverted L

Hi All, I would like to build a good high power common mode choke for 160m. I have a piece of RG393/U ptfe 10mm coax. (1 meter) I was thinking of using this and make me a "W2DU style" choke. Searching for the ferrite cable cores, i found on the Mouser website 2 types which would fit:

Topband: Common mode current and QRN on 160m

I had never used baluns on any antennas for 45 years . . . But about a year ago I made a couple of ferrite choke baluns . . . one for my 160m dipole, one for my W3DZZ, just to see if made any difference to the local noise (from electrical garbage) - the designs were recommended to me by G3TZQ.

Topband: Common mode current and QRN on 160m

I have built up a simple switch box to use on 160m which reduces the QRN a bit on the band so that I can see the weaker stations out there. My noise level is usually s9 and am going to try a 1:1 current balun at the antenna feed point which is a 45mm dia 6m high pole bottom fed. I have about 15

Re: Topband: Common Mode RF Currents Disrupting JT Transmissions

Well said! I have *never* seen a better source of relevant information. Period! 73, Mike www.w0btu.com On Feb 17, 2017 7:01 PM, "Goldtr8 (KD8NNU)" wrote: Read the information in the links from Jim Brown. Once you understand what he is explaining, it becomes easier to

Re: Topband: Common Mode RF Currents Disrupting JT Transmissions

Message- From: Paul Kiesel via Topband Sent: Friday, February 17, 2017 2:40 PM To: topband@contesting.com Subject: Topband: Common Mode RF Currents Disrupting JT Transmissions Hello - I'm not able to run more than 150 watts when using JT65 on 160. RF gets into the computer and disrupts

Re: Topband: Common Mode RF Currents Disrupting JT Transmissions

What is the rf grounding system for the antenna? If it's adequate then there shouldn't be any rf on the outside of the coax. If it isn't then you're bringing part of the antenna into the shack. Ferrites are a band-aid in this case. Wes N7WS On 2/17/2017 12:40 PM, Paul Kiesel via Topband

Re: Topband: Common Mode RF Currents Disrupting JT Transmissions

Paul, Loading the coax with ferrites might make a difference, but I don't think that's a good way to address the problem. If there's RF in the shack, that probably means it's being reflected from the antenna. With or without a ground at the shack, the antenna/load should absorb all the power

Topband: Common Mode RF Currents Disrupting JT Transmissions

Hello - I'm not able to run more than 150 watts when using JT65 on 160. RF gets into the computer and disrupts the JT signal. I don't have this problem on 6m where I run QRO using JT65 on EME. I installed ferrite beads on all radio and computer leads, with multiple beads on coax cables. My

Topband: Common Mode Chokes Etc.

http://audiosystemsgroup.com/RFI-Ham.pdf Nice writeup! Jim/k2hn _ Topband Reflector Archives - http://www.contesting.com/_topband

Topband: Common Mode currents via Antenna Switch(Ungrounded)

I have the following Transmit antenna questions, relative to Common Mode. Please let me describe what I have. Linear30'RG213W0MLY 5 position Coax Switch in shack.(Does not Ground unused centers) with 3 antenna ports used:Then at the W0MLY Inputs:Antennas:(1)160M Inv. L(Infamous Bird

Re: Topband: Common Mode currents via Antenna Switch(Ungrounded)

On 8/6/2014 2:50 PM, Hugh Valentine wrote: I have some RF in shack/house/computer which usually manifests when use the OCF dipole at High Power. No surprise, an OCF dipole is a common mode current generator, and it's very difficult to choke it, especially for high power, because the high

Re: Topband: Common Mode Chokes

My thanks to K9YC, KZ1W and everyone else who replied. Steve WB6RSE 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

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: 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

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