That is consistent with the tuner measurements article in QST some years back. Murch was a rugged component tuner. Still good if you can find one. Most tuners are limited by goodness of the balun. Fo
This was not my experience. I purchased a Murch transmatch new in the early 70's and it operated fine at low power for several years. After acquiring an L4B amp, the insulation on the roller coil fai
Murch tuner failed? Maybe you had the smaller model. I have seen a giant one, and a smaller box. I was thinking the larger one was being referenced as they are common in ham fests here, but not the s
The discussion of "tuners" brings back memories, including the Harvey Wells I had around 1955. Which had a limited matching range and a tendency to arc with a high SWR at about 150 watts. I still hav
I had to run to the farm - the Murch is an UT-2000, no suffix. Forgot to take a tape measure but it's the larger of the Murches. No SWR meter, that was on either the A or B model. And by the way, jus
I also have a Johnson (well OK, a Nye Viking *identical* clone) 250 watt matchbox with SWR bridge. As these were fairly beefy and built in the AM days, does anyone know what power it can take on SSB,
Author: RMcGraw@Blomand.Net (Robert & Linda McGraw K4TAX)
Date: Tue Jul 1 22:05:24 2003
Stuart: et al I too find most internal tuner baluns to be over rated, especially in complex Z conditions. Thus, I've found the external balun from Amidon, being the W2FMI model rated at some 4 KW, to
As I have been told, the Johnson Matchbox was rated for AM, double sideband, full modulation. I would think that it would be able to used with moderately more power for SSB, but since I am not an eng
Author: RMcGraw@Blomand.Net (Robert & Linda McGraw K4TAX)
Date: Tue Jul 1 23:10:36 2003
Vern has it just about right in my book. Yes the Johnson KW matchbox was rated for legal limit AM in those days. Now just what was legal limit AM way back then. Basically stated it was 1KW DC input t
Author: geraldj@isunet.net (Dr. Gerald N. Johnson, electrical engineer)
Date: Tue Jul 1 23:24:04 2003
250 watts INPUT of AM might produce as much as 200 watts of carrier with modulation to 800 watts on peaks. 1 KW input AM might produce as much as 750 watts of carrier (unless the modulated stage was
An interesting observation is that Roy Lewallen, noted QRP author and Antenna program author, has now on his web site, a retraction of his former suggestion that it was better to put the balun at the
Author: geraldj@isunet.net (Dr. Gerald N. Johnson, electrical engineer)
Date: Wed Jul 2 04:08:16 2003
So long as the balun transformer is not considered to be bothered by core saturation and hasn't stray c and leakage inductance (e.g. theoretically perfect, not real world) it makes little difference
Jerry, Very useful and insightful comments on baluns, tuners and feeding balanced antennas! My recent field day experiment with external vs. internal balun was only a surprise in that no heating had
Just as wide low SWR bandwidth on an antenna can be because of significant loss resistance (as opposed to radiation resistance), a wide bandwidth with a tuner may be an indication of high losses. Al
Well, we made QSOS, so it was not lossy configuration but the nature of larger than wavelength loops used on harmonic bands. (Double Zepps have this same characteristic when used on harmonics). What
I have the Johnson Matchbox here, and in use currently, and got it to work on 30 meters by running another tap off of the variable cap that has the end fed wire tap. All I did was install another tap
Actually I have done that...picked a quiet portion of several bands and ran several minutes of "testing" messages at 100 watts out. The Murch components were all cool to the touch and the Vectronics