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Thread: Scatter Forager - wide pattern bi-directional "Slot" antenna Reply to Thread
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  Topic Review (Newest First)
2011-09-18 07:16 PM
300ohm Basically, find a flat surface and use 2 wide boards.
2011-09-18 06:22 PM
dheian A pedestrian question, but what technique does one use to make the 45 degree bends on the mesh? Just grab a set of pliers and bend one wire at a time?
2011-02-25 02:32 PM
strudel.chris
Quote:
Originally Posted by 300ohm View Post
It sure will. You lose anywhere from 6 to 24+ db in the attic.
With those attic loss numbers, it sure is tempting to wander around my yard with a ladder, a broomstick, my antennas, and my netbook with a USB ATSC tuner and TSReader!
2011-02-25 02:03 PM
300ohm
Quote:
I don't know if that'll give me the extra gain to possibly capture any of my farther-away stations or not.
It sure will. You lose anywhere from 6 to 24+ db in the attic.
2011-02-25 01:11 PM
strudel.chris I moved the 'scatter forager' slot antenna into the spot that my large 2-bay VHF antenna occupied.

Reception-wise, they seem pretty similar.
(Except for the slot antenna is considerably more manageable than the 2-bay VHF beast!!!)
The slot antenna does seem to reject multipath interference better, though.
It also doesn't seem to suffer from dropouts every time a truck drives by on the the street in front of the house, too.

What I really want to do is get my antennas out of the attic, and on to the roof of either the garage or house.
I don't know if that'll give me the extra gain to possibly capture any of my farther-away stations or not.

I just have to sort out the best (and yet least frustrating) way to ground the setup first.
2011-02-24 11:56 AM
strudel.chris Well, I got my slot antenna constructed last night.

From my initial channel scan, it seems to perform pretty well, but I should have set it up where my 'old' 2-bay VHF antenna sits.

I'll have to try moving it after work tonight, so I have a better "A to B" comparison between the 2-bay and the slot antennas.



An attic antenna setup may be convenient for experimenting, but it sure is a multipath/hotspot nightmare.
2011-02-22 08:47 AM
strudel.chris It will have to wait until this evening after work, but I definitely want to grab my wire cutters and try making a slot antenna!

The part that intrigues me the most is the reception pattern, which could work well for my 2 vhf-hi stations that are about 180 degrees apart.

Thanks for the advice, ota canuck!
I'll report back with my findings.
2011-02-21 10:06 PM
ota_canuck If you use the cm7777 with the switch in the separate mode, then the scatter forager in the VHF input & the UHF antenna input would be kept separate UHF only.

I wouldn't rule out that KMSP-DT. It may only be a fair weather channel though. The forager should do better for the VHF than the bowtie antenna. If you mount the forager high enough and use it as a bidirectional for channel kttc to the front of the antenna & kmsp to the back of the antenna.
2011-02-21 09:03 PM
strudel.chris I have a cm7777 that I'm using, so I assume VHF & UHF are nicely separated?


Channel 10 is the real channel.
My TvFool report.

I'd love to get KMSP-DT FOX9, but at -8.4dB and 73.7 miles away, I'm sure that would require one heck of a tower and antenna setup.
2011-02-21 06:33 PM
ota_canuck I can only give you my suggestions based on my own antenna trial experiences.

I would suggest using a piece vertical 20" wide x 32" high and then cut a vertical slot 2" wide x 20" long in the center of it. Install the balun wire connections at center or slightly below center of the slot's length. You can tune it down even further if needed by cutting more slot length [up to max 24" slot height] as required. You want to have at least 4" solid areas at the top and bottom though.

Note: The slot antenna will also pick up UHF, so you may need to filter out the UHF band to avoid interfering with other reception from your UHF antenna. Maybe some other members can recommend the type & use of a suitable filter.

Another question: Is 10 the RF[real] channel or is it the psip[virtual] channel?
2011-02-21 06:00 PM
strudel.chris
Quote:
Originally Posted by ota_canuck View Post
What size is the piece of mesh you have to work with?
If I remember correctly, it's a 40"x36" piece.
2011-02-21 05:54 PM
ota_canuck What size is the piece of mesh you have to work with?
2011-02-21 05:50 PM
strudel.chris I have some leftover hardware cloth (I believe it's 1/2"x1/2" grid) from my M4 antenna experiments last summer.

I was wondering if someone would have some suggestions for how to make a slot antenna with this material, specifically for VHF-HI stations?
Possibly tuned for VHF 10?

I have a VHF10 station that is currently being received with an over sized 2-bay.
While it does work 'pretty well', I wonder if a hardware cloth VHF-HI antenna might serve me better.

The 2-bay seems awfully susceptible (2-3 seconds of pixelation/breakup) to vehicles driving in front of my house, even though the VHF10 station is 'behind' the house 20-ish miles.

I'd be curious to try a DIY yagi, but I'm concerned that my precision (or lack thereof) in construction skills might hinder its performance.

Thanks in advance for any suggestions!
2010-08-17 08:59 PM
loveota I like the NEC patterns for VHF & UHF freqs. This version seems to work pretty good . I couldnt resist getting the cutters out and sticking her in the the j-mount on the tower.
I made it 28" tall , used 22" for the width but the outer 2" sides were bent in 45 deg. CM 7777 amp.
Vhf 12.1 and Fox66 was very strong , 24 just strong enough , 35 & 54 no show but I`m needing 7-9 db for UHF to be steady as this model is only 3-5. None the less very impressive range. I`ll leave it on the tower for awhile and see how it does over time .
2010-08-17 11:21 AM
ota_canuck wildwillie,

I have a feeling it would have worked out better if I'd had a 28" screen. The side 45° bends are only structural, I don't believe those bends would make much difference in performance.

Hey,.. post an nec2 plot if you have one.
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