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Search: Posts Made By: tripelo
Forum: Antennas 3-Jun-2020, 1:37 PM
Replies: 11
Views: 720
Posted By tripelo
Most antenna analysis considers the antenna is in...

Most antenna analysis considers the antenna is in free space.
That is far away from earth or any electromagnetic material (conductors in particular).

Stacking antennas close to earth (or...
Forum: Antennas 1-Jun-2020, 7:48 PM
Replies: 3
Views: 265
Posted By tripelo
Nice work, Bob. Wonder where you...

Nice work, Bob.



Wonder where you obtained the 'C' channel.

Wonder if Home Depot or Lowes has it?
Forum: Antennas 26-May-2020, 9:11 PM
Replies: 11
Views: 720
Posted By tripelo
Yes it might. Have examined a few of those. ...

Yes it might.

Have examined a few of those. Those examined here are not good quality.
The connection inside was pressure contact, probably very light pressure contact.

The parts that grab...
Forum: Antennas 26-May-2020, 6:09 AM
Replies: 11
Views: 720
Posted By tripelo
They? See one image. It is open combiner...

They?

See one image. It is open combiner case.

-------------------------------------------

There could be other difficulties, but a noticable one is:

A difficulty with combining UHF with...
Forum: Antennas 29-Apr-2020, 8:57 AM
Replies: 1
Views: 1,996
Posted By tripelo
Yes, could be Radio Shack antennas. In one of...

Yes, could be Radio Shack antennas.
In one of the VHF antenna images, can see a feature common to Antennacraft.
For many years, Antennacraft was owned by Radio Shack.



Yes, you are right,...
Forum: Antennas 21-Apr-2020, 4:00 PM
Replies: 1
Views: 658
Posted By tripelo
Probably Winegard (available in late 60s thru...

Probably Winegard (available in late 60s thru 70s).


http://forum.tvfool.com/attachment.php?attachmentid=3701&d=1587484030




Yes, looks like it is bi-directional.
Forum: Antennas 18-Apr-2020, 1:52 PM
Replies: 39
Views: 6,011
Posted By tripelo
Interesting idea, using RG8 with RG11 connector. ...

Interesting idea, using RG8 with RG11 connector.



Guessing from your image, probably RTV silicone would be a good candidate.
(Avoid silicone that contains acid, some use acetic acid, smells...
Forum: Antennas 17-Apr-2020, 6:50 PM
Replies: 3
Views: 603
Posted By tripelo
Conical Yagis

Yes.

It is a stacked pair of conical Yagis. Very popular TV antenna in the 1950-1970 time range.

The Conical Yagi covers both high and low VHF channels with moderate gain.

The conical...
Forum: Antennas 13-Apr-2020, 3:13 PM
Replies: 2
Views: 759
Posted By tripelo
It is probably an Amphenol VHF (both Hi and Low)...

It is probably an Amphenol VHF (both Hi and Low) antenna, or a clone. This is one of the first antennas to cover both Low VHF and High VHF. As marked in image below, it was available in 1951.
...
Forum: Antennas 11-Apr-2020, 5:27 PM
Replies: 39
Views: 6,011
Posted By tripelo
Thanks for the image. The location of the...

Thanks for the image.

The location of the single antenna may be a better location with respect
to multipath (likely ground reflections).

Best current guess; the problem is external and...
Forum: Antennas 11-Apr-2020, 1:35 PM
Replies: 39
Views: 6,011
Posted By tripelo
Reference 2nd and 3rd images in previous post: ...

Reference 2nd and 3rd images in previous post:

http://forum.tvfool.com/showpost.php?p=62791&postcount=8

Since the 'East Antenna Only' and the 'West Antenna Only' showed evidence
of phase...
Forum: Antennas 10-Apr-2020, 5:49 PM
Replies: 39
Views: 6,011
Posted By tripelo
The blue trace (antenna pair) shows a dip in...

The blue trace (antenna pair) shows a dip in middle of RF 8 spectrum.
That is indicative of two signals interfering with each other (out-of-phase).

An out-of-phase condition can result from:
...
Forum: Antennas 7-Apr-2020, 7:21 PM
Replies: 39
Views: 6,011
Posted By tripelo
Interesting project, Bob. Yes true. ...

Interesting project, Bob.



Yes true.

Many models that I have seen, especially at UHF, fail to account for everything that can affect results.
Partially because NEC2 makes it difficult...
Forum: Special Topics 27-Mar-2020, 9:28 PM
Replies: 14
Views: 17,275
Posted By tripelo
Thanks bobsgarage, for asking the question. ...

Thanks bobsgarage, for asking the question.



Thanks ADTech, for your response.

Probably not what most of us would like to hear.

But, it is good to know.
Forum: Antennas 4-Aug-2019, 6:49 PM
Replies: 5
Views: 2,687
Posted By tripelo
JFD & Area Special Antenna

Yes, second that. Thanks bobs. Interesting antennas.

The top antenna in the 1st image above is a JFD UHF/VHF combo.

http://forum.tvfool.com/attachment.php?attachmentid=3469&d=1564943779

...
Forum: Antennas 9-Apr-2019, 6:03 PM
Replies: 3
Views: 2,886
Posted By tripelo
JFD Zig-A Log

Top antenna, probably:

JFD Zig-A-Log (image below)

http://forum.tvfool.com/attachment.php?attachmentid=3354&d=1554832918

.
Forum: Antennas 5-Apr-2019, 3:06 PM
Replies: 10
Views: 5,195
Posted By tripelo
Thanks, good to be able to appreciate...

Thanks, good to be able to appreciate accomplishments of the past.



Yes, agreed.

Rabbit73 & bobsgarage, it is interesting.

The antenna engineers of the early 50s thru about mid 70s did...
Forum: Antennas 3-Apr-2019, 6:33 PM
Replies: 10
Views: 5,195
Posted By tripelo
Channel Master TW: Traveling Wave Antennas

The antenna is a Channel Master 'TW' antenna. TW for traveling wave.
It was a revolutionary antenna in its day.

Previously, relatively high-gain antennas were narrowband (Yagis).
...
Forum: Antennas 2-Jan-2018, 4:19 PM
Replies: 121
Views: 538,928
Posted By tripelo
A Tower & Antenna Evolution

The tower shown in previous posts has been in use since 1971. It is located in Russell County, KY. The earlier posts showed some antennas that have been resident on the tower. Hopefully, a series...
Forum: Antennas 24-Jun-2017, 1:16 PM
Replies: 121
Views: 538,928
Posted By tripelo
Compare: Antennas Direct DB8e & CM-4228HD

(continued from previous post)

Part 4. Compare 6 antennas (DB8, DB8e, 4228, 4228HD, 91xg, HDB91x)

Having earlier measured four other high-gain UHF antennas relative to the HDTVi antenna, this...
Forum: Antennas 24-Jun-2017, 1:15 PM
Replies: 121
Views: 538,928
Posted By tripelo
Compare: Antennas Direct DB8e & CM-4228HD

(continued from previous post)

Part 3. Data Collection & Analysis

The amount of data collected represents:

Number of UHF channels: 23
Measurements per channel
DB8e4 and 4228HD: 9
HDTVi:...
Forum: Antennas 24-Jun-2017, 1:14 PM
Replies: 121
Views: 538,928
Posted By tripelo
Compare: Antennas Direct DB8e & CM-4228HD

(Continued from previous post)

Part 2. Images of Three Antennas at Test site

The following are images of the two antennas at the test site (antenna center height=25 feet).

Image below shows...
Forum: Antennas 24-Jun-2017, 1:14 PM
Replies: 121
Views: 538,928
Posted By tripelo
Compare: Antennas Direct DB8e & CM-4228HD

Antenna tests conducted on June 15, 2017.

Objective: Compare performance of selected VHF antennas while receiving DFW TV channels.

Antennas:

1. Terk HDTVi (as reference)
2. Antennas Direct...
Forum: Antennas 6-Jul-2016, 3:33 PM
Replies: 121
Views: 538,928
Posted By tripelo
Part 5 (continued from previous post) ...

Part 5 (continued from previous post)

Specifications, Measurement, Analysis and Discussion

In an effort to reconcile the various gain and SWR numbers available for these two antennas, the...
Forum: Antennas 6-Jul-2016, 3:32 PM
Replies: 121
Views: 538,928
Posted By tripelo
Part 4 (continued from previous post) 4NEC2...

Part 4 (continued from previous post)

4NEC2 Analysis and Discussion

Antenna simulation software (4NEC2) could be useful in comparing antennas. Generally, software analysis is not a substitute...
Showing results 1 to 25 of 141

 

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