Re: Topband: Beverage transformer and testing
On 2/5/2018 8:23 PM, Grant Saviers wrote:
I also use wire wrap wire. The Kynar insulation is designed to not cut
thru against a sharp corner wire wrap post, no need to insulate
ferrite. I use 26 or 30 gauge. Multi colors are fun and available in
small spools on ebay in both gauges. No messing with Xacto scraping off
the polyimide insulation on magnet wire is another big plus. A small
multi-gauge wire stripper is a good investment to prevent nicks. Hakko,
Klein, and Ideal make them, check Amazon.
Grant KZ1W
On 2/3/2018 15:36 PM, donov...@starpower.net wrote:
I wind matching transformers for receiving antennas with 30 AWG
wire wrap wire. A BN73-202 binocular core will accept up to 18 full
turns (36 passes). The insulation is very tough and it will not short to
the ferrite core. The insulation is so tough that you'll need a wire
stripper intended for 30 AWG wire wrap wire.
Here is an article about the dangers of ferrite cores damaging
the insulation of magnet wire. Like Grant, I've been using
Kynar ("wire wrap") wire for years on my binocular cores.
https://groups.io/g/BITX20/attachment/27529/0/clifton%20Labs%20IMD%20in%20Broadband%20Transformers.pdf
Rick N6RK
_
Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Beverage transformer and testing
I also use wire wrap wire. The Kynar insulation is designed to not cut thru against a sharp corner wire wrap post, no need to insulate ferrite. I use 26 or 30 gauge. Multi colors are fun and available in small spools on ebay in both gauges. No messing with Xacto scraping off the polyimide insulation on magnet wire is another big plus. A small multi-gauge wire stripper is a good investment to prevent nicks. Hakko, Klein, and Ideal make them, check Amazon. Grant KZ1W On 2/3/2018 15:36 PM, donov...@starpower.net wrote: I wind matching transformers for receiving antennas with 30 AWG wire wrap wire. A BN73-202 binocular core will accept up to 18 full turns (36 passes). The insulation is very tough and it will not short to the ferrite core. The insulation is so tough that you'll need a wire stripper intended for 30 AWG wire wrap wire. https://www.adafruit.com/product/1446 26 AWG stranded wire from old telephone cables also works very well, will not short to the ferrite core and is very easy to strip. A BN73-202 binocular core will accept up to 14 turns. 73 Frank W3LPL - Original Message - From: "Mike Waters" To: "MR TREVOR DUNNE" Cc: "topband" Sent: Friday, February 2, 2018 6:04:01 PM Subject: Re: Topband: Beverage transformer and testing The instructions are at www.w0btu.com/Beverage_antennas.html To test it, put a 450 ohm resistor on the high impedance winding and an antenna analyzer on the low-Z. And make sure there is infinite resistance between each winding and the core, as 73 material is conductive. 73, Mike www.w0btu.com On Feb 2, 2018 9:59 AM, "MR TREVOR DUNNE" wrote: Hi I know it's probably been covered here hundreds of times but I'm looking to make a matching Transformer for a 550ft beverage to 75 ohm coax, I have so bn73-202 cores Also how can I test it once it's built _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Beverage transformer and testing
I always line the holes in those cores with irradiated polyolefin HST. You just have to stretch it a little, and it will easily pull into the holes. (Photos at www.w0btu.com/Beverage_antennas.html#Beverage_Antenna_Transformers Then we can just use magnet wire, 24, 26, or 28 AWG. I mostly use #26. The larger the wire, the better chance that it will survive a lightning-induced surge even with protective GDTs. Two turns on the low-Z winding are all that are needed. 73, Mike www.w0btu.com _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Beverage transformer and testing
Thanks to everyone who has replied to me, guess I'll never know how good it would have worked with 3Y0Z cancelled, Trevor EI2GLB - Original Message - From: Stan Stockton To: MR TREVOR DUNNE Cc: topband List Sent: Fri, 02 Feb 2018 16:20:14 - (GMT) Subject: Re: Topband: Beverage transformer and testing Put a 600 ohm resistor or something close across the secondary leads where the beverage would be connected and hook up an analyzer to the primary wires and see what you read on your analyzer. Check it from about 1.5 to 5 mhz and you should see a good SWR over that range and more. 73...Stan, ZF9CW On Fri, Feb 2, 2018 at 10:33 AM, MR TREVOR DUNNE wrote: > Hi I know it's probably been covered here hundreds of times but I'm > looking to make a matching Transformer for a 550ft beverage to 75 ohm coax, > > I have so bn73-202 cores > > Also how can I test it once it's built > > Thanks > Trevor > EI2GLB > _ > Topband Reflector Archives - http://www.contesting.com/_topband > _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Beverage transformer and testing
I wind matching transformers for receiving antennas with 30 AWG wire wrap wire. A BN73-202 binocular core will accept up to 18 full turns (36 passes). The insulation is very tough and it will not short to the ferrite core. The insulation is so tough that you'll need a wire stripper intended for 30 AWG wire wrap wire. https://www.adafruit.com/product/1446 26 AWG stranded wire from old telephone cables also works very well, will not short to the ferrite core and is very easy to strip. A BN73-202 binocular core will accept up to 14 turns. 73 Frank W3LPL - Original Message - From: "Mike Waters" To: "MR TREVOR DUNNE" Cc: "topband" Sent: Friday, February 2, 2018 6:04:01 PM Subject: Re: Topband: Beverage transformer and testing The instructions are at www.w0btu.com/Beverage_antennas.html To test it, put a 450 ohm resistor on the high impedance winding and an antenna analyzer on the low-Z. And make sure there is infinite resistance between each winding and the core, as 73 material is conductive. 73, Mike www.w0btu.com On Feb 2, 2018 9:59 AM, "MR TREVOR DUNNE" wrote: Hi I know it's probably been covered here hundreds of times but I'm looking to make a matching Transformer for a 550ft beverage to 75 ohm coax, I have so bn73-202 cores Also how can I test it once it's built _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Beverage transformer and testing
The instructions are at www.w0btu.com/Beverage_antennas.html To test it, put a 450 ohm resistor on the high impedance winding and an antenna analyzer on the low-Z. And make sure there is infinite resistance between each winding and the core, as 73 material is conductive. 73, Mike www.w0btu.com On Feb 2, 2018 9:59 AM, "MR TREVOR DUNNE" wrote: Hi I know it's probably been covered here hundreds of times but I'm looking to make a matching Transformer for a 550ft beverage to 75 ohm coax, I have so bn73-202 cores Also how can I test it once it's built _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Beverage transformer and testing
Hi Trevor, Simply terminate the high impedance side of your transformer in a 470 ohm resistor (or almost any other resistor) and use an antenna analyzer to measure the input impedance of the transformer. The reading should be consistent the impedance ratio of the transformer. Sláinte Frank Donovan W3LPL - Original Message - From: "MR TREVOR DUNNE" To: "''topband List''" Cc: "MR TREVOR DUNNE" Sent: Friday, February 2, 2018 3:33:32 PM Subject: Topband: Beverage transformer and testing Hi I know it's probably been covered here hundreds of times but I'm looking to make a matching Transformer for a 550ft beverage to 75 ohm coax, I have so bn73-202 cores Also how can I test it once it's built Thanks Trevor EI2GLB _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Beverage transformer and testing
Put a 600 ohm resistor or something close across the secondary leads where the beverage would be connected and hook up an analyzer to the primary wires and see what you read on your analyzer. Check it from about 1.5 to 5 mhz and you should see a good SWR over that range and more. 73...Stan, ZF9CW On Fri, Feb 2, 2018 at 10:33 AM, MR TREVOR DUNNE wrote: > Hi I know it's probably been covered here hundreds of times but I'm > looking to make a matching Transformer for a 550ft beverage to 75 ohm coax, > > I have so bn73-202 cores > > Also how can I test it once it's built > > Thanks > Trevor > EI2GLB > _ > Topband Reflector Archives - http://www.contesting.com/_topband > _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Beverage transformer and testing
Hi I know it's probably been covered here hundreds of times but I'm looking to make a matching Transformer for a 550ft beverage to 75 ohm coax, I have so bn73-202 cores Also how can I test it once it's built Thanks Trevor EI2GLB _ Topband Reflector Archives - http://www.contesting.com/_topband
