RE: [drakelist] MN2000 balanced feeders
I have had great success here with what is essentially a 135 foot inverted vee fed with 300 ohm twinlead. I use a DX Engineering 1:1 balun mounted outside the house, with a short section of RG-8 leading into the shack (and the MN-2000). That way I don't have to worry about bringing in the twinlead. The 1:1 balun keeps the impedance on the transmission line from dropping too low as might happen with the 4:1 balun. I did slightly change the length of the twinlead (should be approx 108/F) to find a perfect match on all bands. --Ed G- _ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Bill Ellis Sent: Sunday, June 01, 2008 1:45 AM To: [EMAIL PROTECTED] Subject: [drakelist] MN2000 balanced feeders Has anyone been able to adapt the MN2000 for use with open feeders? Bill, WB9CAC
Re: [drakelist] MN2000 balanced feeders
Darrell Bellerive [EMAIL PROTECTED] made an utterance to the drakelist gang -- While a balun on the output side of a tuner will couple some energy it may not be very efficient at some impedances. A balun, whether 1:1 or 4:1, is designed for a specific characteristic impedance. In most ham radio applications the transmitter side impedance is designed for 50 ohms unbalanced. So in a 1:1 balun the antenna side should have a resistive impedance of 50 ohms balanced and a 4:1 balun should have a resistive impedance of 200 ohms balanced. As the antenna impedance changes from the designed characteristic impedance by reactance and/or resistance, the efficiency and transformation ratio will deteriorate. Just how much will depend on the design of the balun windings, the core material, and the resistance and reactance of the load. As many point out, it will still work. One can lose as much as 6 to 10 dB or more in a tuner, balun, and feedline and still make lots of contacts. QRP operators prove this all the time. Heating of the core material is one indicator of lost power, but remember that the lost power will heat a small core to a much higher temperature than a large core. So just because the core does not get too warm, doesn't mean power isn't being lost to heat. Modern automatic antenna tuners are hard to beat for ease of operation, but for the highest efficiency it is hard to beat the old link coupled tuners for balanced line applications. All electrical systems are compromises between a number of variables such as efficiency, cost, ergonomics, size, weight, availability of materials, etc. Just be sure you understand the compromises you are making. 73, Darrell VA7TO On Monday 02 June 2008 03:12, Ed G wrote: I have had great success here with what is essentially a 135 foot inverted vee fed with 300 ohm twinlead. I use a DX Engineering 1:1 balun mounted outside the house, with a short section of RG-8 leading into the shack (and the MN-2000). That way I don't have to worry about bringing in the twinlead. The 1:1 balun keeps the impedance on the transmission line from dropping too low as might happen with the 4:1 balun. I did slightly change the length of the twinlead (should be approx 108/F) to find a perfect match on all bands. --Ed G- -- Darrell Bellerive Amateur Radio Stations VA7TO and VE7CLA Grand Forks, British Columbia, Canada -- Submissions:drakelist@zerobeat.net Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net --
Re: [drakelist] MN2000 balanced feeders
[EMAIL PROTECTED] made an utterance to the drakelist gang -- Bill, Yes, the Drake B-1000 balun (which will cost half the price of the MN-2000) will enable use of balanced lines with the MN-2000. However, whether it works well or not is yet to be determined. Baluns are not designed to work over a large range of impedances and if the impedance presented at the terminals is too high/low, then there will be loss and heating. But it often does work. 73, Evan**Get trade secrets for amazing burgers. Watch "Cooking with Tyler Florence" on AOL Food. (http://food.aol.com/tyler-florence?video=4&?NCID=aolfod000302) -- Submissions:[EMAIL PROTECTED] Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net --
Re: [drakelist] MN2000 balanced feeders
[EMAIL PROTECTED] made an utterance to the drakelist gang -- Hi Bill, I have connected a 4:1 balun at the output of the tuner and it has worked fine. 73, Mike On 31 May 2008 at 22:44, Bill Ellis wrote: Has anyone been able to adapt the MN2000 for use with open feeders? Bill, WB9CAC -- Submissions:[EMAIL PROTECTED] Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net --
Re: [drakelist] MN2000 balanced feeders
Gary Poland [EMAIL PROTECTED] made an utterance to the drakelist gang -- Bill, I have done the same ... 4:1 balun, 450 ohm line feeding a 80 meter inverted vee. You may have to play around with the feedline length to get a low SWR on some bands. I remember I had a problem with 10 meters. 73, Gary W8PU -- Submissions:[EMAIL PROTECTED] Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net --
Re: [drakelist] MN2000 balanced feeders
Dennis Monticelli [EMAIL PROTECTED] made an utterance to the drakelist gang -- I have a MN2700 and rather than search and pay excessively for the rare Drake balun, I elected to use a Johnson Matchbox Jr as a balun substitute. The Matchbox makes a much better balun than a typical core balun. It handles a wider range of impedances and does so with both ow loss and excellent feedline balance. As another post noted, you can play with feedline length to get an unbalanced tuner with toroid balun to yield a low SWR and you can play the same game with a Matchbox all by itself. But by using the Matchbox together with the unbalanced tuner makes life easier. On those bands where the impedance falls into a convenient range for the Matchbox alone, I run the MN2700 straight through and use only its metering capabilities. For the odd band or two where the Matchbox cannot bring the SWR all the way down, I engage the MN2700 to reduce say a 2:1 or 1.5:1 down to a 1:1. The feedline balancing afforded by the Matchbox works just as well when transforming the antenna Z down to say 100 ohms vs taking it all the way down to 1:1. The overall loss of the unbalanced tuner plus Matchbox is lower than that of the unbalanced tuner plus toriod balun because each component is working within an impedance range that is close to design center vs the toriod balun working well outside its design Z and the unbalanced tuner having to correct for a high residual SWR that may well have a high reactive componet (ie. hi Q). The match made with the tuner plus matchbox will usually be of lower Q, which means broader bandwidth. They make a great combo and the Matchbox costs less than the Drake balun. Dennis AE6C On Sun, Jun 1, 2008 at 6:06 AM, [EMAIL PROTECTED] wrote: [EMAIL PROTECTED] made an utterance to the drakelist gang -- Bill, Yes, the Drake B-1000 balun (which will cost half the price of the MN-2000) will enable use of balanced lines with the MN-2000. However, whether it works well or not is yet to be determined. Baluns are not designed to work over a large range of impedances and if the impedance presented at the terminals is too high/low, then there will be loss and heating. But it often does work. 73, Evan ** Get trade secrets for amazing burgers. Watch Cooking with Tyler Florence on AOL Food. (http://food.aol.com/tyler-florence?video=4?NCID=aolfod000302) -- Submissions: [EMAIL PROTECTED] Unsubscribe: [EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost: [EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net -- -- Submissions:[EMAIL PROTECTED] Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net --
[drakelist] MN2000 balanced feeders
Has anyone been able to adapt the MN2000 for use with open feeders? Bill, WB9CAC
