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In Reply to: RE: Rhombic done and posted by cootcraig on December 28, 2013 at 20:48:10
While the signal is stronger for the station at 15deg, the sound is bad. I will start on the second rhombic. Construction should go faster the second time around.
Follow Ups:
from the tuner. Multi-path (MP) is the other issue - and clearly the problem with that station off your first rhombic.MP is the reason why a directional antenna with gain -aimed at the desired station - is always better than any omni-directional, let alone a titchy little powered thing aka a waste of money.
My comments re a map were driven by your mention of a 15degree station.
I am not surprised that station sounds bad.
The good thing about rhombics, as you'll recall from the article, is that their pattern's width or arc can be quite wide or quite narrow - depends on how you arrange it. Varying between a square with one of the two (equal-length & long) axes pointing at the station/s OR a very flattened rhomboid with the much longer axis pointing at the desired stations / town or city - if you were out in the countryside.
Warmest
Tim Bailey
Skeptical Measurer & Audio Scrounger
Edits: 01/03/14 01/03/14 01/03/14
> Timbo in Oz wrote:
>
> The good thing about rhombics, as you'll recall from the article, is
> that their pattern's width or arc can be quite wide or quite narrow -
> depends on how you arrange it. Varying between a square with one of
> the two (equal-length & long) axes pointing at the station/s OR a very
> flattened rhomboid with the much longer axis pointing at the desired
> stations / town or city - if you were out in the countryside.
I'm starting work on the antenna aimed at 15deg. In the Audio article
by Richard Kaufman I haven't found mention of flattening the antenna
to make it more directional. If I flatten it as you say that will
make it more directional that should be a help on this station. It will
also make it a little easier to fit in the space I have.
Thanks for the idea.
He talks about apex angle quite a bit and you'll notice that while he points out a square example - once - for a square room, most of those depicted are flattened rhombics.There's also the twin overlapping model.
I don't have a rhombic though I have considered it as it might be able to do UHF and VHF duty, though the gain at UHF might be very high. Also, everything we listen to / watch (90% of all FM stations) are on the one big tower. I'd then only have one external antenna - a cap-and-coil tuned AM random wire.
I've been put off the task because the roof-space is full of fibreglass, about 5" of crumbed / loose topped by two layers of batts. Bastard of a place to work in even in winter, thanks to all the loose fibres.
Instead I am going to revisit the array on the big tall mast calmped to the house, and at least replace the current FM duty antenna with an FM-8. I may also replace the current VHF TV antenna with a 7/7-11. Redo all the cabling on the mast to the combiner and then the down lead to the splitter under the house, with quad shield RG6 with pure copper centre wire.
It's all mostly RG11 at present - which I got for free - but is very stiff and hard to work with.
LBNL the PDF of the article in FAQs is not loading for me. Were you having trouble with it?
Warmest
Tim Bailey
Skeptical Measurer & Audio Scrounger
Edits: 01/05/14
> Posted by Timbo in Oz
>
> He talks about apex angle quite a bit and you'll notice that while he
> points out a square example - once - for a square room, most of those
> depicted are flattened rhombics. There's also the twin overlapping model.
I'm thinking about a portable setup to take for FM dxing while camping.
> I don't have a rhombic though I have considered it as it might be able
> to do UHF and VHF duty, though the gain at UHF might be very high. Also,
> everything we listen to / watch (90% of all FM stations) are on the
> one big tower. I'd then only have one external antenna - a cap-and-coil
> tuned AM random wire.
>
A stand alone AM loop is my next antenna project.
> I've been put off the task because the roof-space is full of fibreglass,
> about 5" of crumbed / loose topped by two layers of batts. Bastard of
> a place to work in even in winter, thanks to all the loose fibres.
Well, I slipped on a paint mask and charged ahead. In addition to
all the loose fiberglass I scraped lots of roof sheathing tacks.
The good news is I've yet to fall through the drywall below.
> Instead I am going to revisit the array on the big tall mast calmped
> to the house, and at least replace the current FM duty antenna with an
> FM-8. I may also replace the current VHF TV antenna with a 7/7-11. Redo
> all the cabling on the mast to the combiner and then the down lead to
> the splitter under the house, with quad shield RG6 with pure copper
> centre wire.
>
> It's all mostly RG11 at present - which I got for free - but is very
> stiff and hard to work with.
>
> LBNL the PDF of the article in FAQs is not loading for me. Were you
> having trouble with it?
I grabbed a local copy when I found it.
LOL, you'd need a big camping ground!
Warmest
Tim Bailey
Skeptical Measurer & Audio Scrounger
It is difficult to know where the horizontal beams are to avoid that possibility.
IF I'd known about rhombics a long time ago .........
Warmest
Tim Bailey
Skeptical Measurer & Audio Scrounger
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