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W1VT

Joined: Sat, Apr 4th 1998, 00:00 Roles: N/A Moderates: N/A

Latest Topics

Topic Created Posts Views Last Activity
Antenna analyzer vs feedline type Sep 21st 2012, 14:37 1 997 on 21/9/12
USB to Serial Port problems--Prolific Drivers Aug 3rd 2012, 18:27 1 1,215 on 3/8/12
Italian Phishing emails! Dec 13th 2011, 14:20 1 1,137 on 13/12/11
John K0GMO needs help designing SS Amp Nov 17th 2011, 15:53 1 1,016 on 17/11/11
1 Farad Capacitor to Eliminate Headlight Flicker? Oct 19th 2011, 13:14 4 1,786 on 9/11/11
History of Relay Rack Dimensions? Oct 17th 2011, 12:58 2 1,246 on 25/10/11
Miswired Selsyn Oct 13th 2011, 17:51 1 1,072 on 13/10/11
Stealth Antenna wire Sep 12th 2011, 12:51 2 1,584 on 13/9/11
Designing a ham bench Aug 29th 2011, 12:38 2 1,670 on 29/8/11
Can't find recent Hint and Kink Aug 26th 2011, 13:01 1 1,533 on 26/8/11

Latest Posts

Topic Author Posted On
What is an accepted range for a DX contact? WN6WJN 3 days, 13 hours ago

http://www.arrl.org/distance-records
As you can see, when you get to the higher amateur bands, even 100 miles is enough to set records.

Zack Lau W1VT
ARRL Senior Lab Engineer
RF Suppressor Ground System KK6CXF 3 days, 18 hours ago

The best way to handle the second floor shack grounding issues is to run coax from the antenna to single point ground that is line of sight and bonded to the electrical service entrance, and then bring up the coax to the 2nd floor station. Some antennas, such as verticals and long wires, may require a good radial system for decoupling, as ground rods are typically inadequate. A balanced antenna, like a center fed dipole, will often work with just ground rods. A half wave dipole is likely to be the easiest antenna to get working well from a 2nd floor station.

Zack Lau W1VT
ARRL Senior Lab Engineer
looking at MFJ 31' vertical /portable antenna KB9YUT 5 days, 13 hours ago

Instead of leaving a dipole up, perhaps you could install support ropes that can be used for future operations?

Zack Lau W1VT
ARRL Senior Lab Engineer
Air Conditioner RFI KD4LN 5 days, 18 hours ago
Quote by NZ2Z
I just moved into a new home and am contemplating where to put the shack in the basement. On one side is the incoming power, and Internet/cable feed. Very close to that are 3 ac external units. I need to determine a location for the radios as well as the location for a sleeve to feed the antenna wire from the shack to the outside antennas. I can locate the radios anywhere inside, but the antenna wires will in all probability have to come out near the ac ac units. Is there any general guidance on 1) how far from the ac units or electrical power box (outside) to place the radios, and 2) if it is a good idea to have the antenna coax exit the shack near the electric box or the ac pads?

Bob - KG2RP


Ideally, there should be a line of sight path from your service entrance to your shack's single point ground--that way, if there is lightning strike on the service wiring, there will be a simple and direct path to the station grounding. Typically, lighting will take a path through the home instead of going around a corner to follow a bad ground path.

The service entrance ground and the single point ground can be the same, but you will need to work harder remove electrical noise from the single point ground. Ground rods aren't as effective as a good radial system in decoupling noise from grounds.

In terms of overall station performance, it may be worthwhile to sacrifice a little bit of transmit signal if you can significantly reduce the noise on receive--typically, we are talking about a fraction of a dB on transmit and many dB on receive, if there is a low SWR on the transmission lines.

Zack Lau W1VT
ARRL Senior Lab Engineer
G5RV to Remote Auto Tuner KD5DRY 6 days, 11 hours ago

As pages 7 and 8 of the instruction manual for that tuner explain, you can and do run into matching issues--you can't really expect this tuner to handle any load you throw at it.

A G5RV can be a good antenna on several bands if put up high, but I do run into a lot of hams that are frustrated if they can't get good performance on every band--a G5RV falls short of this expectation. In contrast, while the Inverted-L requires more work to set up properly, it is much more likely to work as an all band antenna. More importantly for a lof of hams, the Inverted-L needs less space.

One also has to realize that efficient wire antenna interact with nearby antennas, wires and metal structures--antennas with "problem" bands will vary unpredictably depending on location.

In theory, one could swap baluns to optimize performance--using a 4:1 balun for high impedance loads, a 1:4 balun for low impedance loads, and a 1:1 balun for moderate impedance loads. In practice, folks want to use one balun for everything.

Zack Lau W1VT
ARRL Senior Lab Engineer

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