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Author Topic: T2FD Antenna  (Read 38831 times)

Offline ChrisSmolinski

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T2FD Antenna
« on: March 25, 2008, 0011 UTC »
Has anyone here used one? I've been thinking of setting one up, to supplement my assortment of dipoles for each band.

Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
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Offline Pigmeat

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Re: T2FD Antenna
« Reply #1 on: March 25, 2008, 0018 UTC »
George Maroti uses one and told me he likes it. He might be the man to contact on this one.

Offline Sealord

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Re: T2FD Antenna
« Reply #2 on: May 20, 2008, 1405 UTC »
I have an RF-Systems T2FD that I've used off & on.  It was my main antenna back in 2000 & as recently in 2006 until I switched to the EWE.  It was a great performer overall, but I wasn't satisfied with the high angle rejection & needed something a little more directional.  It did make for a great one-stop-shop setup for the HF spectrum as a whole.  If I was forced to choose only one antenna for all applications & band segments, it would be the one.
« Last Edit: May 21, 2008, 0201 UTC by Sealord »
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Offline ChrisSmolinski

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Re: T2FD Antenna
« Reply #3 on: October 21, 2008, 2025 UTC »
A few weeks ago, I finally put up my T2FD. I went with one 131.5 ft long, so cut for 2500 kHz and up. I'm using a 12:1 balun and feeding it with 100 ft of RG6-U 75 ohm coax. The center termination resistor is 800 ohms.

The high end is perhaps 50 ft up, the low end about 20 ft, and it slopes to the south. Not my preferred orientation, but you take what the trees give you.

I'm really amazed with the reception. While the signal is generally an S unit or two lower than that from one of my dedicated dipoles (for the 90, 60, 48 and 43 meter bands), the noise is much less, hence a much better signal to noise ratio. And it works everywhere on HF, I don't need to keep flipping between antennas.

Performance on the high end of the MW band is also excellent (as compared to an approximately 500 ft long random wire). Performance is much worse on the low end, as expected.

I'm really pleased with the results. I'm actually very close to removing the antennas switch, and just connecting this as my only antenna. It's that good.


Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
NRD 545 / netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 670 ft horizontal loop / 500 ft northeast beverage / 270 ft west-south-west beverage / 300 ft south beverage / 43m / 20m / 10m  dipoles / Crossed Parallel Loop

Offline Lex

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Re: T2FD Antenna
« Reply #4 on: October 22, 2008, 1331 UTC »
Between these reports from Jon-FL, Chris, Sealord and others I've chattered with online, the T2FD sounds like a winner.  I've compared audio clips from Jon-FL, Sealord and other folks in the Florida area, and am continually impressed with the low static levels compared with designs other than the T2FD and Sealord's ewe.

Funny, when I bought my copy of Joe Carr's receiving antenna handbook many years ago the original G.L. Countryman design from which the T2FD was derived was rather lightly regarded and dismissed by some folks as either obsolete or too much of a compromise.  Supposedly it was popular on military installations but I wasn't into radio back in the '70s and didn't pay attention to the radio setups on the various bases where I was stationed.

I have a huge back yard at my apartment complex that's virtually unused.  Hmm... I wonder how well a T2FD would work with a 100-yard run of coax feedline, which is the closest I could get to the property border?
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Offline ChrisSmolinski

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Re: T2FD Antenna
« Reply #5 on: October 22, 2008, 1521 UTC »
Since coax loss at HF is typically very low, I don't see a 100 yard run causing major problems. 100 yards of RG-8 results in a 3 dB loss - half an S unit. Even crappy RG-58 only doubles that to 6 dB, and RG-58 isn't really even coax ;-)



Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
NRD 545 / netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 670 ft horizontal loop / 500 ft northeast beverage / 270 ft west-south-west beverage / 300 ft south beverage / 43m / 20m / 10m  dipoles / Crossed Parallel Loop

cmradio

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Re: T2FD Antenna
« Reply #6 on: October 22, 2008, 2226 UTC »
Even crappy RG-58 only doubles that to 6 dB, and RG-58 isn't really even coax ;-)

You mean that stereo patch cable that CB good buddies instist is for RF? :D ;D

Peace!

Offline Pigmeat

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Re: T2FD Antenna
« Reply #7 on: October 31, 2008, 1702 UTC »
Even crappy RG-58 only doubles that to 6 dB, and RG-58 isn't really even coax ;-)

You mean that stereo patch cable that CB good buddies instist is for RF? :D ;D

Peace!

LMAO!!!

A good 75% percent of my tx'es over the years have been made with antennas consisting of nothing but Dollar Store speaker wire for feedline and antenna. They cost less than two bucks and when the feedline gets so twisted it's not working well,I split it for the next antenna's legs and buy another 100 feet of the same stuff. The stuff is actually lower loss than RG-58.

With a third hand tuner I've been heard across most off North America for the better part of a decade on 10-14 watts of AM and close-out wire. LOL!!!

Offline ChrisSmolinski

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Re: T2FD Antenna
« Reply #8 on: October 31, 2008, 1909 UTC »
LMAO!!!

A good 75% percent of my tx'es over the years have been made with antennas consisting of nothing but Dollar Store speaker wire for feedline and antenna. They cost less than two bucks and when the feedline gets so twisted it's not working well,I split it for the next antenna's legs and buy another 100 feet of the same stuff. The stuff is actually lower loss than RG-58.

With a third hand tuner I've been heard across most off North America for the better part of a decade on 10-14 watts of AM and close-out wire. LOL!!!

Ahh... you've been using ladder line!
Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
NRD 545 / netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 670 ft horizontal loop / 500 ft northeast beverage / 270 ft west-south-west beverage / 300 ft south beverage / 43m / 20m / 10m  dipoles / Crossed Parallel Loop

cmradio

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Re: T2FD Antenna
« Reply #9 on: October 31, 2008, 2227 UTC »
He made it audiophile grade for better modulation - he can sell the dollar store wire now for $50/metre ;D

Peace!

Offline Pigmeat

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Re: T2FD Antenna
« Reply #10 on: November 01, 2008, 1433 UTC »
You're not far off,I've actually had one stolen since the price of copper has gone up. I left it up a tree for later use,when I came back it was gone.

One of the things that separates FM pirates from SW pirates,IMO,is the cheapness on the SW side. A FM pirate will put together a twenty-thirty thousand dollar studio for a 1-5 watt station. Most SW pirates wouldn't spend hard cash on studio equipment if they had money in piles. They're down at the pawn shops and thrift stores wrestlin' the staff for half off on a beat-up mixer or trying to get that fifty cent twenty year old Walkman for a nickle.

It's that ol' hamfest mentality the SW guys come out of.

Glad the antenna worked out for you Chris. I don't have that kind of room but I may try a smaller version. I've got favorable trees towards W.Europe. I could use the thing for listening to Euro-pirates.

cmradio

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Re: T2FD Antenna
« Reply #11 on: November 02, 2008, 0210 UTC »
You're not far off,I've actually had one stolen since the price of copper has gone up. I left it up a tree for later use,when I came back it was gone.

Oh geez!

I wonder if they read today's Report on Business, where copper took its biggest single day loss ever!

They might do better stealing aluminum.


Quote
One of the things that separates FM pirates from SW pirates,IMO,is the cheapness on the SW side. A FM pirate will put together a twenty-thirty thousand dollar studio for a 1-5 watt station. Most SW pirates wouldn't spend hard cash on studio equipment if they had money in piles. They're down at the pawn shops and thrift stores wrestlin' the staff for half off on a beat-up mixer or trying to get that fifty cent twenty year old Walkman for a nickle.

It's that ol' hamfest mentality the SW guys come out of.

I can't really argue there.

They key to great audio is the studio and processing equipment. If one doesn't put any effort into purchasing or designing the multi-band compressor/limiter, even more so for the amplitude modulation modes, they should stay away from the hobby.

Can always pick out the AM pirate - crappy audio. Or it could just be Radio Cairo ;D

Peace!
« Last Edit: November 02, 2008, 0213 UTC by cmradio »

Offline spore

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Re: T2FD Antenna
« Reply #12 on: December 30, 2009, 1816 UTC »
A friend told me the Corps of Engineers used the B&W version of the 
T2FD at a few sites and wasn't impressed with performance. Basically your trading bandwidth for performance since the far ends of the antenna wires terminates in a high value dummy load to lower the SWR. in these times of low solar activity (naming the few sunspots and all  ;D ) antenna performance (or lack there of) is more evident. at the peak of the cycle a wet string draped across your shack can get you around the world.

When reading reviews of antennas, like on eHam, ALWAYS notice the date and correlate it to the solar cycle.

.

Offline ChrisSmolinski

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Re: T2FD Antenna
« Reply #13 on: December 30, 2009, 1941 UTC »
There's no doubt that signal levels are lower with the T2FD than a dipole cut for the given band (i still have several dipoles to compare to). But, the overall signal to noise ratio is superior with the T2FD vs any of my single band dipoles (all of which are fed with coax to a balun).

YMMV, and I only receive, I don't transmit.

Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
NRD 545 / netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 670 ft horizontal loop / 500 ft northeast beverage / 270 ft west-south-west beverage / 300 ft south beverage / 43m / 20m / 10m  dipoles / Crossed Parallel Loop

cmradio

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Re: T2FD Antenna
« Reply #14 on: December 31, 2009, 0248 UTC »
...and I only receive, I don't transmit.

 :o

You were my hero :(

LOL! :D


Peace!