Tag Archives: Log Periodic

Hard not to be excited about the new Tennadyne T-12Log Periodic Antenna

Tennadyne T-12 Antenna up at 76 ft on Skyneedle at K9ZW Main QTH

The Tennadyne T-12 is up at about 76 ft (23m) but I don’t have the rotator controller set up yet, so it is essential fixed.

Yet the performance already has me enthused!

First day running FT8 in the background (I was pretty busy, so I missed a lot of DX opportunities) netting a bunch of DX – over 40 DXCC entities in 165 QSOs!

In no particular order:

Continue reading

Tagged , ,

Assembling Log Periodic Antennas – Part 2

Another big lift in the process of getting the HF log periodic antennas up. With much help from Vern K9EME, the T-12 is up and initial testing shows it’s performing very well.

There are a lot of steps to do in any antenna project, and this one was no exception.

I’m completing this post Sunday afternoon, as I have had enough feeding the mosquitos for a weekend.  Pictures with brief comments (and yes, the project is not done yet):

The Skyneedle has an offset rotator drive.

 

At the Skyneedle’s lowest elevation it is obvious a few more trees need to be cut back.

Continue reading

Tagged ,

Assembling Log Periodic Antennas – Part 1

Time to (finally) build the Log Periodic Antennas for the home QTH.

The big one is a Tennadyne T12.30-10HD – a twelve element 30 to 10 meter version.

Here is photo borrowed from the manufacturer’s website of a T12 on a tower (mine is going on a Skyneedle):

T12 from Tennadyne Website

Assembling has taken several after work sessions.  Here are some photos:

Boom parts as unboxed

Continue reading

Tagged ,

How a Tennadyne T-12HD arrives – prior to unboxing

The Tennadyne T-12HD I ordered is now all here. The boxes are nicely marked.

Mine came in two groups, a first group of five parcels and a follow up parcel with the truss kit.

Continue reading

Tagged , , ,

Some Assembly Required – Tennadyne T-12HD antenna arrives

Some Assembly Required – Tennadyne T-12HD antenna arrives

Five UPS parcels arrived, two long cardboard tubes, two long boxes and a square box, containing my new Tennadyne T-12 10-30HD Log Periodic antenna.  A sixth parcel with the truss kit is expected to arrive Friday.

This antenna is big enough that it will be a two person assembly job.

I had run a T-8 at my old home QTH, one that I purchased used and after a bit of lightening encounter replaced with a new T-8 a couple years back. That T-8 is going up at my island QTH, hopefully this summer, and is already on the island.

As previously posted, I changed antenna directions dismantling & putting the never installed very large RadioWavz Hexbeam into storage pending technical redesign/upgrades. That RadioWavz has gone radio silent not returning phone calls or emails also factored into my decision.

Having had excellent experience with the decade plus T-8 as my main antenna, another Tennadyne was high on my list to take the main position on the home Skyneedle tower. I’ve cut & pasted the basic claimed specifications:

  • Model    T12.10-30HD
  • Coverage in MHz    10 – 30
  • Boom Length    36 FT
  • Gain/dbd/dbi*    8.0/10.1
  • Longest Element    53 FT
  • Elements    12
  • WT.     115#
  • Turning Radius (ft)    27.6
  • Wind Load (sq.ft)    16.21

Some differences between the T-12HD and the T-8 which interested me:

* The T-12HD should tune 30m, which the smaller T-8 did not do very well at all.
* My Station should have a gain improvement of close to 3dB which is always appreciated for RX and can’t hurt on TX (or would allow running lower power) vs the old T-8 based station, plus any effect for being up another 20ft (6m)
* The T-12HD is a trussed-boom construction vs the untrussed T-8 (not certain if that is ultimately good or bad)

Here is a picture taken from the Tennadyne website of a T-12 (presume standard vs my new HD model) at another ham’s station:

Tennadyne T-12 (Tennadyne’s website photo)

There are some integration advantages for a LPDA (Log Periodic Dipole Array) antenna when running a Flex-6000 based station, as the LPDA tends to present an acceptable SWR to the radio or if running QRO the PGXL amp, when used within the LPDA’s design frequencies. Typically the ham band optimization matches other ham designs while respectively the non-ham band lower performance you would see from other non-actively tuned beam antenna designs is avoided or minimized.

I found both barefoot and running QRO with the T-8 was basically a no-tuner required situation, one that I hope the T-12HD matches.

Link to Tennadyne antennas: http://www.tennadyne.com

73

Steve
K9ZW

[Edited on 15JAN21 to correct formatting and photo insertion problems with original posting, and capture that mine is arriving in six parcels rather than five parcels]

Tagged , , , ,