"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=aolfod00030000000002) > > ---------------------------------------------------------------------- > 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 ----------------------------------------------------------------------
