I had some odd SWR readings and not sure why, the antenna is not located in an ideal location. I have it on my balcony 6 floors up below are the SWR readings both good and bad.?

OK. I posted on this a few months ago but cant find original post so I'll do again.

I've got a super three rod mounted in a plastic box. Attached in parallel is an L type attenna tuner like an MFJ. I've wrapped a few more turns around the center of the rod and coupled a trimmer (fixed) cap which I took from the super three board across the output. It resonates proper up to about 1 MegHz but above that tunes only on strong local stations. I'm testing on weak daytime stations and it works well on 910kHz with some added inductance from the antenna tuner but at 1240 it's very weak with no added inductance. I have more trimmer caps of different colors that I can cannibalize from the super 3 board but don't know how to adjust them or what values the colors represent. They look very fragile like an adjustment might break them. The one I'm using now is white. Would adding another trimmer cap across the output move the bandwidth up, or would it lower the freq?

开云体育

If your not familiar, here is the link to everything:?

Never used.?

Includes ...
Quantum QX Loop V2.0 with MW Plug-in, Tropical/SW Plug-in, and LW Plug-in
Quantum Q-Stick
Quantum Coupler

Approximately $550 worth for $275 plus shipping from Connecticut.

Now -that- is the way to do it. A link does not take up space, and it is available in the Links section for future use.

Steve Greenfield AE7HD

You cannot link to a file in that way, Yahoogroups provides a temporary link that only works for 20 minutes at most.

This is a message for all: Please do NOT use high ASCII characters in file names. I cannot make a link to the file now, and I am also unable to change the name or delete it so I can reupload after renaming.

I did finally find a workaround.

In future, please post files with names in English so as to avoid all high ASCII characters, and if it is a file on a website, please post a link rather than uploading it. We have only 100MB of file space. I just had to spend a lot of time cleaning out the Files area on another list.

Here is the company that the PDF came from:


Steve Greenfield AE7HD
your friendly but sometimes grumpy neighborhood moderator

Hi Danny,
i uploaded a file where some features of toroid ferrites are written.
the name is "caracteristiques tores ferrite_hftoxxxx.pdf.
I use it frequently.

http://f1.grp.yahoofs.com/v2/UEvVUrtr49Rl-BA9sSgfDzPRZNVTiNmC-kx824aPC9StuOHqu8pc3FMdx9vlK_gvjxX2wy_2CCY1vixeC_bLYKu8YBvHzgUlfFMm9IkzQKCECgXrjtB5z3nxGolztNAEV4OBLihr-ObCQqNBFO6YjUCN9vgTUtNWe_3UH8iL4ri3e9RK6lGi/caract%C3%A9ristiques%20tores%20ferrite_hftoxxxx.pdf

Patrick F61112

I was recently reviewing online designs for homemade DTV antennas.? Most of these designs are for UHF (channel 14 and up) and are of the general design of multiple V dipoles with a phasing line, in front of a reflector screen.? These antennas are directional, and have to be aimed at the transmitting tower.? In my particular location, rural open space with no multipath problems, I wanted an omnidirectional antenna (or at least one with 180 degree coverage) that covered VHF high 174 MHz up through UHF.

Searching through Internet postings for omnidirectional DTV antennas, I found a couple of descriptions for horizontal loop antennas.? THese have been constructed of? 1/2 or 3/8 inch copper tubing, in a horizontal loop of about 26 inch diameter, feeding a standard television 300 to 75 ohm balun and coax cable.? They are typically supported with a horizontal PVC cross and mounted outside on a roof.? In one design the loop is a complete circle except for a gap at the feed point.? In another design there is also a gap 180 degrees across from the feed point.

I tested this design by picking up a slightly damaged aluminum bicycle rim (about 22 inches diameter) for two dollars at a used bike shop.? I cut out a one inch gap and attached a balun transformer with two screws through existing spoke holes.? I tried this antenna indoors horizontally on a table next to a large window, and picked up 14 digital channels, both VHF and UHF.? Based upon the signal strength meter in the TV, this antenna was omnidirectional on some stations, and semidirectional on others.? On those channels where there was some directionality, it seemed to favor the feed end of the loop.? It still had a wide beam width on these channels, though.

I made a second horizontal loop out of heavy wire so I could test the effect of a gap 180 degrees from the feed point.? This increased the signal strength on some channels, but caused me to lose other channels, so I only got 11 instead of 14.

The aluminum bicycle rim is cheap, rigid, rustproof and easy to come by.? It will be easy to mount horizontally outdoors, where I expect it to perform even better.? This might be a good platform for other loop antenna projects as well.

DTV receivers do not handle multipath well, so this would probably not be the best antenna in an urban environment, but for a more open area with various towers in different directions, it seems to work well.

Hi,
I think this chart could be usefull.
the file is uploaded in the "files" section of the group.= caractéristiques tores ferrite xxxx .pdf

73
Patrick
http://f1.grp.yahoofs.com/v2/lBfUUsX54ZdtPA76L_0f8FSf8FtkSXVr3BwQ45KcQU6L_5acQik4B9krTFPtVfwoi6yScpM6NeTxcaNVuAAHLC6fcpWF7EmdWKSO0ntku1AlCHahnr_g-s7Ypwf2sglTHLukyAZKkMfeZDpp4YQ8lsvDq_dcZxw74cQ2MOGCzTGSN14DzFMH/caract%C3%A9ristiques%20tores%20ferrite_hftoxxxx.pdf

See if one these sites help you:


73 Dave - AC2GL

the colors are indexed and the data is proably on the mfrs. webpage
------------------------------

Hi group. I have some ferrite of different size and color. I know that some are better for low frequency and other for high frequency. I would like to know how to identify them. Anyone know?on how I can?do this??Thanks

Danny?

Hello Ben,
In your recent mail you asked:

"So...can someone please point me towards the modified M0AYF amplifier? "

Well the schematic shown in Everett Sharp's mails is the modified M0AYF. You
can find the original in:


Cor Beijersbergen

Good evening all,

I'm kind of new here so I have been been reading some of the posts in the online Yahoogroups archive.

I recently built a Mobius loop per Chris Trask's instructions in "Mastering the Art of Shielded Loop Aerials." It works *very* well with the remote varactor tuning, but I would like to try it with a pre-amp in a broadband fashion.

My interest in the loop is to try my hand at receiving LOWFERS, NDB's, and some of the transmissions around 500 kHz.

In reading the archives, I'm trying to find more information on two topics.

First, a post makes reference to a "modified M0AYF amp." In another message there is the statement "Guys, I found that this modified M0AYF amp works much better than the IZ1AG (LZ1AQ?) amp."

I think there was a link that originally followed, but thanks to the awful new Yahoogroups interface I believe it has been stripped out.

Please forgive me if this is easy to find in the archives. I about went mad searching the archives online, I would search for a topic, get a return that looked promising, click on the message and the message loaded was absolutely NOT the same message in the search results! (Thank you Yahoo...)

So...can someone please point me towards the modified M0AYF amplifier?

Second, reading Everett Sharp's (N8CNP) article in the files section on building and evaluating broadband active loops, there is a mention of a modified Kits and Parts Wideband RF Amplifier.

I'm not clear on two things:

- Is the amp fed from the loop via the 1:2 matching transformer?

- Was the Kits and Parts amplifier evaluated on the Mobius loop?

If yes, what was the ground on the pre-amp connected to? I understand in the shielded coax loop it was connected to the shield, but in the Mobius configuration, due to the cross-over at the top of the loop, what is the equivalent of the shield braid?

(Also, if Everett reads this message...my grandmother's maiden name is Sharp, with the story that when her parents came to America, it was changed to Sharp from Skorupski so they would sound more American. If this strikes a bell, we're probably related.)

thanks much and 73,
ben, kd5byb