Mantera Magnum Antenna

As I see it, the antenna output of the transmitter is connected to the wire at the bottom of the coil that extends from the last wrap. (turn) The ground is connected from the transmitter antenna ground to the mast pipe or to whatever ground you choose to use..

And, yes.. The transmitter is in the box mounted to the mast under the antenna..

This antenna is designed for 1.700mhz. and with no provisions for tuning. Also, black P.V.C. pipe is used in the construction. How I understand it, The black stuff isn't the best choice to be making coils with because the pigments in the plastic reacts with r.f. Is there a reason for the black pipe?

How does the wire from the bottom of the coil connect to transmitter?

Welcome aboard!

The center terminal of the antenna output is connected to the bottom end of the coil, and the top end of the coil is connected to the base of the mast (copper pipe), so that the xmtr output flows from the antenna terminal through the coil and then to the mast. The plastic pipe core serves as both an insulator and a structural component holding up the copper pipe radiator

The ground side of the xmtr output is connected to the ground rod or water pipe or what ever else you are using for a ground.

Is there a reason for the black pipe?

As I understand it, the color of the pipe used is not important at AM broadcast frequencies. Again, as I understand it, the notion that the color is important only comes into play at ham band frequencies of very short wavelengths, like 440 MHz. The wavelength of an AM broadcast frequency is hundreds of feet long, and so doesn't really react to the pipe pigment.

Here's a schematic view of the xmtr connections

[img:97261abb3e] [/img:97261abb3e]

Then this antenna model is similar to that of SSTRAN. Not being an electronic expert of any kind I thought that perhaps the black pvc may increase the Q of the coil over the white used by SSTRAN thereby giving better range. As to the Ramsey AM25, that seems to be a lost cause as far as any range goes, as compared to the SSTRAN and Rangemaster with their design and external antennas.

Thanks fellows for all of your help. JimB

Not being an electronic expert of any kind I thought that perhaps the black pvc may increase the Q of the coil over the white

EXACTLY! Finally 🙂 someone outside the regular herd gets it 🙂

Here's the story behind the magnum:

I started in Part 15 Radio just maybe 2 years ago (Has it really been that long already, SCWIS?), and I was trying in vain to get my tx (which was a gizmo ordered from the UK) to transmit more than 2 blocks.

I spent a lot of time with SCWIS over the phone and via email trying to do this. Looking back now, it was my fault I didnt get it working.

Someone introduced me to a Physics Professor from Stanford, and he sends me an email with the very precise instructions that you see in the howto (which now seems like it needs the connection schem added to it).

I ended up with 1 mile of range off the gizmo. Well, it rained, and the antenna filled with water (I didn't realize this at the time), which changed everything. I thought the TX died, so I called my new friend, and he agreed to design and build me a new Part15 tx. This one got a full 100mW at the final, and he came and installed everything for me. We ended up with something like 3 miles of solid range.

The magnum has definately proved itself - enough that there are now several variations of it. Some include the taps, some don't.

Has it really been that long already, SCWIS?

Two years, one hundred pounds and a herina operation! Zip!
Well, I gotta go listen to my new Panteca CD, they ROCK
8)
Oh, wait, it's Manteca and Pantera, how did I screw that up?

" The magnum has definately proved itself - enough that there are now several variations of it. Some include the taps, some don't. "

Are there construction plans for the one with the taps?

Are there construction plans for the one with the taps?

Yes - The SSTran plan[/size:de3342b456] features taps - good for experimentation!

You could also add taps to the Manteca coil by adding more turns and tapping every turn, or every two, three or five turns. Since the Magnum is for 1700 KHz, all lower freqs will need more turns anyway. 💡

I already built one.. 😀

The original Magnum specifically specifies Black PVC. Now was the professor onto something there? I've read through the Forum that it dissipates RF current, yet could Black PVC increase the coil Q possibly like the ferrite slug tuned coils that came out in the late '50's to replace the loop antennas on the All American 5 superhets? By the way, where can I download Winamp 2.8.1 player? Website seems to have the old skin yet not the player itself.

where can I download Winamp 2.8.1 player?

Try www.oldversion.com[/size:eb53db38e1] - lots of good stuff 8)

💡

Newbie here.

Forgive me in case I overlooked this somewhere else on this website, but what is a Mantera Magnum antenna? I tried a search but came up dry.

I do recall reading somewhere about someone who used one of these with the rangemaster to achieve 4 miles of range, but no longer recall who, when or where.

I would certainly appreciate a brief description and perhaps a link to what
jbprtco calls "Building instructions now on home page, I'm confused from step 16 on"..Whose home page?

Many thanks in advance for enlightening me.

Welcome! We had a little spelling error earlier, it's actually Manteca, after the town in Caiifornia 😳

Manteca Magnum[/size:e8ab98347a]

The home page reference is to ours, just click the big antenna pic 😉

💡

jbprptco: The good Professor specifically stated something about black beacause of the soot used to make it black, and something about the Q. As for specifics, I'll have to dig through email. But it was for Black vs. White - the white didn't do something cool that the black did do.

RadioheadC:

Forgive me in case I overlooked this somewhere else on this website, but what is a Mantera Magnum antenna?

- the Manteca Magnum (it's now-official name), and it's construction instructions for 1700 can be found here: http://www.part15.us/modules.php?name=Content&pa=showpage&pid=9

Many thanks for the very helpful quick reply.

One other question: are those rumors about 4 miles true? If so, how was it achieved?