Maco tuner to cover 11m and 10m?

[jwr1221]

Hi guys! I'm currently studying to get my ham ticket so I'm planning on diving in a setting up a base station this spring or summer... I'm shooting for my General class ticket so I'll have priviledges on 10m.

My tentative plan is to use my 257HP and a delta loop as a CB / 10m base... If I build the delta loop for full wave 10m with a 1/4wave 75ohm matching section of coax to get the impedance down to 50ohm on 10m, do you think I'll need a tuner for the SWR to be acceptable on 11m? I'm looking at using a 30 ft mast with the delta loop suspended apex-up.

I saw Redman CB (sponsor) has a Maco 91 tuner for $30 (300W limit) and an RF Limited 1kW tuner for $48... Anyone have any experience / opinions on either of these tuners? Or should I just go with a "trusted" brand and look at the MFJ 901B which can be had for around $90?

Another nifty option I ran across that may come in handy for mobile applications is the MFJ 910 tuner which is a single knob 10-80m tuner for $28 at a non-sponsor ham site...

Of course, this is all depending if I can come up with the greenbacks!!!

What do you think?

-JWR

[19dt2120]

I don't know the Maco but try try to find a 2e hand Zetagi M27 or the Samlex M27 ,they are cheap,good en have enough extra space for some modifications inside.

For making the antenna more broad-banding/better tunable use an openline or 2 parallel 50Ohm coax (using only both center) and a choke-balun .



For some more ideas :
http://www.xs4all.nl/~pa0fri/ ... uadeng.htm

['Doc]

I can't say anything about that Maco tuner, I don' have any experience with one. I can tell you that while you -may- be able to use a 10 meter loop on 11 meters, it isn't going to be the 'best' thing in the world, that's just a fairly long stretch for a too short antenna. An 11 meter loop on 10 meters would probably work better.
I can also tell you that Maco tuner isn't going to have a lot of capability, it just won't have the size of coils and capacitors necessary for a lot of 'tuning'. A 'single knob' type tuner is going to be even more limited.
To simplify things even more, why not use a parallel feed line all the way from the tuner to the antenna? It's not expensive at all, and can handle a much higher SWR (and power) with no trouble at all. It isn't as convenient to run like coax, but it certainly isn't that difficult either.
Even better, how about a loop on a lower band, 40 or 80 meters? With a good tuner and ladder line you can make them work on almost all bands. It really doesn't have to be a loop, any antenna can be multi-banded if you want to make it such.
If you are going to use a tuner, then use a big one. Having the capability but not using it isn't going to hurt anything. A 'too small' tuner is never going to be adequate or a 'good deal'.
- 'Doc

[Night Crawler]

I saw Redman CB (sponsor) has a Maco 91 tuner for $30 (300W limit) and an RF Limited 1kW tuner for $48.

If the Maco 91 can handle 300 watts and the RF Limited can handle 1000 watts I'll eat my hat also the tuning range is limited on both of them if your lucky possibly it might tune 12 meters.

why not use a parallel feed line all the way from the tuner to the antenna? It's not expensive at all, and can handle a much higher SWR (and power) with no trouble at all. It isn't as convenient to run like coax, but it certainly isn't that difficult either.
Even better, how about a loop on a lower band, 40 or 80 meters? With a good tuner and ladder line you can make them work on almost all bands.

That's good advice since your getting your ticket it will enable you to work all the bands if you don't have the space for a 80 or 40 meter loop cut it for 20, 15 or 12 meters it will be able to be tuned on any frequency above what it's cut for.

should I just go with a "trusted" brand and look at the MFJ 901B which can be had for around $90?

The MFJ-901B is the tuner to get it uses a air wound coil for inductance which is my preferrence and also has a 4:1 balun that will enable you to use ladder line.
Don't get the the MFJ-910 it uses capacitive matching with fixed capacitors using a rotory switch without an inductor.

[jwr1221]

Thanks for the advice guys! Couple follow-up questions for you:

The more I look at tuners, the more I'm liking the MFJ-993B autotuner... meter, display and 4:1 balun built in for balanced line... Even though it provides a lot more flexibility, Is balanced line (twinlead, ladder line, etc.) more prone to RF bleed than using coax? (can't just wind a choke in it like you would coax, right?)

In terms of the antenna, I don't have an all-band HF rig; I'll just be using my 257HP so I was just going to focus on 11m / 10m for now. My initial plan was a vertical delta loop, but everywhere I read online, the general consensus is that a horizontal loop not only has a low radiation angle for DX, but is also omni-directional... Highly desirable in my case since I won't have a rotator of any sort... But that assumes it's fairly low to ground... I'm really only going to have one "easily" usable support (the mast) so I'm thinking another option would be to make a circular loop sized for 11m and suspend it concentric with my mast... What do you think?

The tentative plan also includes mounting a dual band 2m/70cm j-pole on top of the mast...

Again, this is all dependent on finances and will probably be closer to spring / summer... I think this stuff is fun though and like doing all the research and "planning" everything out in my head in the meantime!

-JWR

[Nagant]

I use the MJF-993B IntelliTuner. It works well other than I've noticed if I place it real close to an amplifier being used they seem to cause it to go into what I call squirrely tune. As in it can't seem to find the proper tune settings and just chatters on and on. Other than that it works fine. The digital and analogue wattage meters are really accurate on mine as is the SWR measurements. I mainly use it as the tuned input for my Heathkit and therefore I don't use all it's capabilities.

A good little inexpensive tuner to find used is the Dentron Jr. I have one that's really rough looking but the thing will tune about anything. I see them on eBay in the $40 to $50 range for nice looking ones. If you don't care about the looks you can always hold out for an thugly one like mine for less than half the going price. Yeah I'm cheap.

['Doc]

A couple of things you might keep in mind...

Auto-tuners are nice! You don't have to 'mess' with them like a manual tuner. If you get one of the right 'size', they will handle anything your radio will generate as far as power goes, and in frequency.
Now for the "but's".
For the average price of that auto-tuner, you can get a manual tuner that will at least double the ability to handle power and frequency.
A manual tuner requires you to do some 'pre-use' tuning to keep from taking much time to get it set right. But if you keep notes on those settings, and the antenna system doesn't change much, you can certainly go back to those 'usual' settings pretty quickly.
(I don't know about you, but 'fiddling' with knobs and things is sort of fun for me.)
Physical size -does- mean something with tuners. Components of a size to handle more voltage or current tend to be larger than less capable components. The ability to vary component values, variability, determines how 'far' that tuner will be able to 'stretch' things. All of that combines to mean a 'wider ranged' capability will also mean a bigger 'box' to put all those components in. Bigger tuners are 'good'. (Now all you have to do is find a place to put that thing!) Manual tuners have been around for a long time, longer than auto-tuners. That means that there are more of them, which also means they tend to be less expensive.
Also keep in mind that a tuner only handles impedance differences. They don't 'correct' a non-resonant antenna resonant, nor do they 'make up' for other inadequacies. They don't make an imperfect system 'perfect', but they can certainly make one usable. Which is the whole idea. The alternative to using a tuner is to have a lot of antennas that are very well tuned to start with. But how many of us can do that? I can't, I don't have the room.
Losses. Yep, there'll be some loss when using a tuner. In most cases, that loss is going to be much less than if you didn't use that tuner, so, you come out ahead.
If you don't have to use a tuner (of any kind) then don't. If using a tuner makes things 'more better', then why not? Simple...
- 'Doc

[Night Crawler]

My initial plan was a vertical delta loop, but everywhere I read online, the general consensus is that a horizontal loop not only has a low radiation angle for DX, but is also omni-directional.

If you got the consensus online from Amateur operators when they talk about DX that's considered working some exoctic place like the FiJi Islands in that case a vertical loop would be a better DX antenna then a horizontal.
A contact between hams in the Continental United States is usually considered local and a horizontal loop would work fine for that, if your interest is working foreign countries a vertical would be better.
Here's some information about loops. http://www.radioworks.com/nloop.html

Even though it provides a lot more flexibility, Is balanced line (twinlead, ladder line, etc.) more prone to RF bleed than using coax? (can't just wind a choke in it like you would coax, right?)

No, balanced feedline when properly used doesn't leak rf, has less loss and doesn't cost as much as coax.
Open wire feedline, ladder line, twinled what ever you want to call it is balanced so a choke wouldn't be needed.