Huge Improvement in RS double bowtie - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 242 Old 01-26-2002, 09:47 AM - Thread Starter
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I have discovered a way to improve the reception with my Radio Shack double bowtie antenna. My signal strength has gone from 60% to 85% on the one digital channel we can get from Nashville.

The antenna comes with 300 ohm lead-in wire. I had a couple of 300 to 75 ohm transformers in my spares box. I drilled out the rivets that attached the 300 ohm wire to the antenna, and used a couple of bolts to attach the transformer to the antenna. I now use 75 ohm shielded cable from the transformer to the Dish 6000 8VSB card. It really improves the performance of the antenna.
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post #2 of 242 Old 01-26-2002, 11:24 AM
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At some point you must have a 300-75ohm transformer. As you have found, the sooner you can get the signal inside a shielded cable the better.

How did you have the antenna connected before? Did you run 300ohm wire to the set?

-Glenn
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post #3 of 242 Old 01-26-2002, 12:41 PM - Thread Starter
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300 ohm to a transformer with screws and an F connector.
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post #4 of 242 Old 01-26-2002, 02:29 PM
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So basically youve eliminated the 3 or so feet of 300 ohm wire originally attached to the bowtie and used the 300 ohm leads from your 300 to 75 ohm converter and attached them where the original 300 ohm leads attached correct?

Chris
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post #5 of 242 Old 01-26-2002, 02:32 PM - Thread Starter
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That is correct Chris.
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post #6 of 242 Old 01-27-2002, 03:40 AM - Thread Starter
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The transformer I used for the modification has a short piece of 300 ohm cable with spade terminals on one end, and an F connector on the other end that a 75 ohm shielded cable screws on to.
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post #7 of 242 Old 01-28-2002, 05:12 AM - Thread Starter
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Even with a signal strength of 85% on my Dish 6000, I am still getting occasional breakups in my digital picture. I live 45 miles NW of Nashville with lots of mountainous terrain in between. Any suggestions?
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post #8 of 242 Old 01-28-2002, 05:50 AM
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Did you try an amplifier? I got a 2 piece one from Radio Shack (1 piece goes near the antenna, the other near the STB) and it made a great improvement. It was about $39. I went from getting nothing on some channels to being able to watch all of them.

Bob
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post #9 of 242 Old 01-28-2002, 08:06 AM - Thread Starter
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thanks Bob Hammond!
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post #10 of 242 Old 01-28-2002, 10:17 AM
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Bob -

Which Radio Shack antenna did you use? I tried their two piece UHF one this weekend (amplifier at the antenna, power supply at the STB), which was supposed to provide a 20db gain, and saw my signal go from 75-90 on all channels to 0-50. In other words - it got a heck of a lot worse!!! The only thing I can think is that I either got a bad one, or I overamplified the signal...

d-
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post #11 of 242 Old 01-28-2002, 10:31 AM
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It's called the RS Double Bowtie.

http://www.radioshack.com/product.as...%5Fid=15%2D623

Beats their own amplified antenna's.

I'll have to try that mod. Do you have a pic of it? I did the other mod where you run the original wires to the 2 screws at the top and bottom of the antenna...then run another 300ohm wire from those 2 screws to the transformer and into the HD receiver.

I guess I'll try a modified version of your mod by keep the 2 original wires there...then run a short wire to a transformer...then use a shielded cable to the HD Receiver.

Wonders never cease on this $18 antenna.

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post #12 of 242 Old 01-28-2002, 12:14 PM - Thread Starter
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Dizzy,
If you are going to shielded cable on the antenna, you need to remove the 300 ohm cable. You will pick up interference if you just leave the 300 ohm cable hanging in the air.

You can cut the 300 ohm cable at the spade lugs and solder the transformer wires there. That way you do not have to drill out the rivets that attach the spade lugs to the antenna.
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post #13 of 242 Old 01-28-2002, 12:21 PM
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Ahh...thanks!

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post #14 of 242 Old 01-28-2002, 12:43 PM
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I was looking at this antenna the other day but didn't get it because it is UHF only (that's what it says anyway). What do you use for VHF when you use this antenna?

Thanks... Ralph
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post #15 of 242 Old 01-28-2002, 01:43 PM
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Quote:
Originally posted by rcibera
I was looking at this antenna the other day but didn't get it because it is UHF only (that's what it says anyway). What do you use for VHF when you use this antenna?

Thanks... Ralph
Most digital OTA channels are UHF.
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post #16 of 242 Old 01-28-2002, 02:43 PM - Thread Starter
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I have an outdoor antenna which I get all of the analog channels on.

The double bowtie is just for digital.
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post #17 of 242 Old 01-28-2002, 07:04 PM
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Just as a test, I got one of those RS transformers that have the split wires/lugs on one end and the F connector on the other end.

Electric taped the transformer lug to the OEM bowtie lug and plugged a regular coax cable to the STB.

Sample broadcasts of CBS went from 70% to 88-90%!!!!! Who would have thought?

I'll do the solder job next! Maybe I might hit close to 100% for an INDOOR antenna!


Thanks!!!!

This mod works better than the other mod where one plugs the OEM wires to the 2 screws on the top and bottom of the bowtie and then adds another set of wires from those screws to the STB.

As another test, I bought a $39.99 RS pre-amp that's rated for +26. Reception on the above set-up dropped from 70% to 58-59%!!! Even at the lowest turn on the dial...reception didn't improve (I thought I might have turned the amp up too high).


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post #18 of 242 Old 01-30-2002, 12:35 AM
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Dizzy,
Do you have the p/n for the transformer?

Jimmie
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post #19 of 242 Old 01-30-2002, 05:10 AM
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Quote:
Originally posted by Bob Dycus
Even with a signal strength of 85% on my Dish 6000, I am still getting occasional breakups in my digital picture. I live 45 miles NW of Nashville with lots of mountainous terrain in between. Any suggestions?
Bob,

You say you also have an outdoor antenna. Have you tried putting the 6000 on it to see if the breakups go away?

Alex

Alex
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post #20 of 242 Old 01-30-2002, 05:16 AM
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Im using this antenna for a VHF antenna as well and it works fine. See my post a few days back on the mod. Sounds like my mod with this transformer mod will create the perfect antenna!

Whats the part # on the transformer to get guys?
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post #21 of 242 Old 01-30-2002, 05:49 AM
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Sorry, I don't have the model # w/ me. I think I may have bought the wrong thing.

The box said High Gain Inline Signal Amp. This isn't the same thing as a pre-amp is it? On the RS website, they seem to differentiate those that boost signal for long cable feeds (which I think mine is) and the ones that boost signal for antenna reception.
I'll probably return it and try something else.


Thanks!

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post #22 of 242 Old 01-30-2002, 06:37 AM
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Eliminating as much of that twinlead cable as possible definitely helps, and attaching your balun directly to the aerials is a great idea. Where's my drill? Or at least my Dremel tool?

For anyone who hasn't figured it out, you do this:
http://ad1440.net/~kelly/balun.jpg
connecting A to A and B to B on this:
http://ad1440.net/~kelly/ant.jpg
and getting rid of the twinlead altogether.

(My initial mod was to cut the twinlead down and screw down the 3 inches or so that remained to a spare balun---the kind that slips over your equipment's F connector. I put a mating connector on that, and coax onto that, and run the whole thing outside onto the patio.)

I'll give this a go next.

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http://www.seankelly.tv/
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post #23 of 242 Old 01-30-2002, 06:47 AM
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Gotta wonder why they don't sell them with the balun already attached? Surely someone at Tandy noticed that the double bowtie has become something of a hot item in the last couple years, right?

Jim

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post #24 of 242 Old 01-30-2002, 01:33 PM - Thread Starter
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Alex,

My outdoor antenna gets far worse UHF reception than the RS double bowtie.

I went to Radio Shack and got a $9.95 4 way signal amplifier and it appears to clear up my reception problems with the double bowtie.
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post #25 of 242 Old 01-30-2002, 01:46 PM
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My guess is that either Tandy is too dim to figure it out (after all, this is the company that dropped the entirely fun and educational n-in-one electronic project kits, where n is more than 15 or so), or they're trying desparately to increase sales of baluns.

Applying Hanlon's Razor, "Never attribute to malice that which is adequately explained by stupidity," I'd say it's the former.

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post #26 of 242 Old 01-30-2002, 01:58 PM
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Maybe I'm fortunate, but the twinlead works just fine for me.

When I moved into my new house, I discovered that the prior owners had a heavy duty twin lead 300 ohm wire run almost all the way from the attic to the basement, I guess from an old internal antenna. All I had to so was hook up the double bow tie in the attic and extend the twin lead in the basement, and voila!

I get both CBS and Fox 99.9% dropout free. But then, I'm about 15 miles west of the city with a clear line of sight to ESB. That might have more to do with it. :)
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post #27 of 242 Old 01-31-2002, 03:11 AM - Thread Starter
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After a day of testing, it looks like the Radio Shack 4 way signal amplifier combined with the modified double bowtie antenna has cured my dropout problems.

The 4 way amplifier has an LED power on indicator, an FM trap which is switchable, a pot for adjusting the gain (24dB typical), gold plated connectors, and is the cheapest ($9.95) that Radio Shack sells. The Radio Shack part number is 15-1167, and on the package it says, Remote-Powered 4-Set Distribution Amplifier.
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post #28 of 242 Old 02-01-2002, 05:52 AM
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All the RS's around the DC area seems to be sold out of this item ($9.95 distributer amp). One manager told me its been discontinued and that they will not get anymore....

Bob:
How much is shipping from TN to MD? Can you grab me one if there's anymore there? I'm an authorized paypal member. Thanks!

Dizzy
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post #29 of 242 Old 02-01-2002, 07:04 AM
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Quote:
Originally posted by Dizzy
All the RS's around the DC area seems to be sold out of this item. One manager told me its been discontinued and that they will not get anymore....

Bob:
How much is shipping from TN to MD? Can you grab me one if there's anymore there? I'm an authorized paypal member. Thanks!

Dizzy
You can order it on RS website or by phone.
http://www.radioshack.com/product.as...%5Fid=15%2D623
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post #30 of 242 Old 02-01-2002, 10:27 AM - Thread Starter
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Dizzy,
I looked at the Radio Shack website and the 15-1167 amp I bought is now 15-1168 and sells for $39.95.

The store I got mine from still has one in stock.

I don't know anything about Paypal because I use credit cards over the internet.
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