I built an antenna, and I've got some questions. amateurradio

I built a 70cm directional biquad antenna, and it seems to be working pretty well; using my Baofeng GT-3 II, I've reached a couple of repeaters with good "ears" at >35km at low power (nominally 1 W) full quieting, and I've hit repeaters at >50km on high (5 W). The beam width seems fairly narrow, going from a clear signal to crackly fuzz (reported by another helpful ham) at maybe 30 degrees off-target, but only on transmit; when receiving, it doesn't seem to matter which way I'm pointing the thing. I can turn around in a full circle, point the thing up in the air, turn it sideways, stand in front of it, and anything else; it still seems to receive without much trouble, although moving it around sometimes finds dead spots. Is this unexpected behavior? Am I getting RF on the shield that needs to be cancelled out, or is this just some property of this antenna design?

Also, if anyone wants pics and a build report, I'll put up an album, but it ain't pretty; the whole thing is a quick-and-dirty first build, and it's a slightly fiddly implementation. It's got a driven element of 1/4" OD copper "refrigerator line" and a reflector made of a 1'x1' 28-gauge steel panel and a 70x50cm rectangle of hardware cloth. I've got a type-N connector as a connection point on the back.

Submitted February 16, 2017 at 12:36PM by semininja http://ift.tt/2lNOyej amateurradio

My MEGA BUNNY EARZ construction quest (ongoing) amateurradio

As I don't consider myself mechanically inclined, this is easily the most ambitious (and probably dangerous) thing I've ever attempted: raise a 20-foot-tall steel pipe off my balcony, to which is attached a rigid V dipole with traps for the 10 through 40 meter bands. I call it the MEGA BUNNY EARZ.

Long story short, I couldn't do it alone. Just raising the pipe itself, with nothing attached, from the ground to the second floor balcony, laying it back onto the roof, and then shimmying it down into a concrete base was a hair-raising three minutes. Bringing it back down to the ground again was even scarier. With the antenna attached, and the matching network box, and the control cable, and the coax, and the guy wires.... nah, I'd totally kill myself. I'm going to need a spotter. I'm not Arnold Schwarzenegger, or even Arnold Schwarzenegger's tax accountant's chihuahua.

This is as far as I got before I had to give up because of time (and rain). The steel pipe (which is far, far heavier than I first imagined it) is leaning against its balcony support. When raised it will be sitting in a concrete base on the balcony, anchored to this support, and further supported by guy wires.

http://ift.tt/2i8wlq8

I bought this at the recent hamfest event back in December. It comes with a tuner at the feedpoint that you control remotely via a switch near the radio side. I had to assemble the switch from instructions:

http://ift.tt/2iXlf4J

I'm sure my late grandfather, who knew me in my youth as a bumbling fool who could barely tie my own shoes, would have been impressed to see that finally learned how to a) solder and b) follow instructions:

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POWER ON:

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Here's the tuner side, with the 4 control wires all connected. I bought 15m (50 ft) of 6-wire cable, leaving two wires dormant:

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And ready for mounting onto the mast pipe:

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Lastly I have to make guy wires. This necessitated a whole other batch of gear:

http://ift.tt/2i8t4Hn

But once I get this sucker into the air, then finally I'll have something more robust than a couple of wires that are always coupling with the aluminum siding and robbing me of power. I'll be sure to crow enthusiastically about it when I actually get it up there.

Or you will read my SK article "died like a chump trying to raise a mast". And as this is something I've never done before, I'm paralyzed with fear. I've planned it for months but am still wary I've forgotten something. What if I do it wrong and the whole thing collapses and caves in the neighbor's house and my wife divorces me and I end up living under an overpass in a refrigerator carton? Akljafhsldkfhalsdhfajklsdhfklf

Bonus: This is my new common mode filter. It was made by Diamond Antenna, who I hope makes antenna gear of higher quality than their spelling suggests. Spot the typos!

http://ift.tt/2iXhqwb

Submitted January 10, 2017 at 11:45AM by the2belo http://ift.tt/2jyWgrA amateurradio

One weird trick to calibrate your KX3. Elecraft hates it! amateurradio

For the past 8 months I've been doing a Reddit pass around of an Elecraft XG50 signal generator used to do the extended VFO temperature compensation procedure on a KX3. I've run out of people to send it to and I don't want it back in my house.

Doing the calibration on your Elecraft will make your KX3 much more stable when transmitting full duty cycle modes like JT65. The procedure isn't very hard to do and you get to amaze your loved ones by putting your rig the refrigerator.

There is no cost except for the postage required to send the XG50 on to the next person.

PM me your name, callsign, address and email, and I will add you to the pass around list.

Submitted November 10, 2015 at 08:47PM by MonkeybutlerCJH http://ift.tt/1MxMbC8 amateurradio

Magnetic Loop for 20 Meters Help amateurradio

Hello everyone, I moved to an apartment so the big old dipole I'd been using had to go. I whacked together a simple magnetic loop antenna over the weekend using a 3kV open-air capacitor and some (very thin) refrigerator copper tubing.

I can receive, and the tuning cap indeed does its job, but I have only managed one very weak contact on transmit.

I have two main questions:

MOST IMPORTANTLY: When I begin to TX, I turn down the output power on my Icom IC-737 to the minimum possible, throw it in AM, and tune for 1:1 swr. This is always possible on the 20m band (1:1). Only after checking and re-checking that my SWR is <<1.5 do I switch back to SSB and turnh up the juice. Is this the safe, best practice for using a magnetic loop? I don't want to unwittingly damage my 737. When I use AM and turn the power up to the full output, I noticed that there is a brief arc across the cap plates, so I no longer turn it up all the way, though I have never seen arcing in SSB even with full power and full modulation under test. What effectg could arcing have on my transmitter if it is noticed immediately?

SECONDLY: Presumably, based on the pacific66 calculator, I am getting very poor efficiency due to the tubing I used being about 0.5cm in diameter. Is it worth it for me to use that thinner tubing as the faraday fed loop, and then go buy the proper length of 3/4" or greater copper coiled tubing?

Any general magloop info is welcomed here. I have read everything pertaining to magloops in the archives and a lot of the information is contradictory or too introductory.

(I am licensed btw, I just prefer to remain semi-private) Thanks everyone!

http://ift.tt/1eGfzcc

Submitted June 24, 2015 at 02:40AM by SpoopyLoops http://ift.tt/1JhjzN0 amateurradio

Help with high noise floor amateurradio

Hi there! I'm new to Reddit, so please excuse me if I'm stepping on any toes. I joined only because of this very active and insightful community.

TL;DR: My club's station has had some 10m success by day, but has also seen punishing broadband S7-S9 noise floors. We can't move our QTH, and our QTH is the office of a tech company in San Francisco, which means we need to find ways to modify our equipment to help with the noise floor.

Due to a series of fortunate events, I am now a newly-minted Extra, and I'm also the president of a small club founded in my workplace...and my employer was kind enough to gift our club a Kenwood TS-590 transceiver to get started. I am still working out all the red tape with building management to install our first HF antenna on the roof of our office; until then, I bought a Buddipole which we can set up and take down as need be. Our office has a large concrete deck on the 4th story of the building which connects to one of our commons areas. When we want to operate HF, we set up the Buddipole on the deck (east-west, perpendicular to the line of the building so as to not radiate back into it), run the coax back into the building through a door, and set up the transceiver and its power supply on a table in the commons.

This worked great the first time we did an operating event. 10m sounded quite nice, we got some great QSOs and had our turns in pile-ups on special events stations. As the sun set, 10m closed out and we tried 40m, where we heard many, many stations but could not seem to be heard for some reason. We considered this a very successful day for our scrappy rig.

The second event was a complete disaster. Same arrangement as before, with the Buddipole outside the building on our deck, perpendicular to the building, and the transceiver inside. It was after sunset, and we tried every band 40m-15m, and we couldn't hear anything over the S7-S9 noise floor that followed us everywhere. The noise floor was so smooth and uniform that I didn't even notice I'd tuned so far off one of the bands that I started picking up a commercial shortwave broadcast!

My club's really looking to me for guidance on getting consistent results, and I don't know enough to really even start being effective. The setup I've described above is completely as-is. I haven't started adding chokes to the feedline or the DC power lines, for example. Because everything has to be done as a temporary setup, we don't know how to connect up a station ground (and, in fact, I read controversy about whether or not it helps). Power, Kenwood, Buddipole...that's it on the equipment.

To throw in some extra x-factors, it's worth noting that we're operating out of downtown San Francisco and that our office is a tech company. We really can't change those things; everyone at the club has their life centered around their workplace and most live near work, and we can't really change the fact that there are hundreds of computers, wireless networking equipment, fluorescent lights, motors for refrigerators, etc, etc, etc. I've read some articles on RFI control that often encourage using common mode chokes on the sources of interference, but this isn't a home environment. Supposedly, the outer layer of the building is an RF shield, and I had hoped that just getting the antenna outside would help, but it clearly wasn't enough.

So, given the limitations that I have, what can I do to try and drive down the noise floor more reliably? Like I said, we've had a successful day of 10m operating before, so I know it's possible for us to use the setup, but I don't really understand how or why this massive noise floor has hit us or what to do about it.

Submitted December 01, 2014 at 01:14AM by roadriverrail http://www.reddit.com/r/amateurradio/comments/2nv8m3/help_with_high_noise_floor/ amateurradio

My first dedicated shack rig for HF DX, Data, CW and contests amateurradio

I'm about to buy my first dedicated shack rig for HF DX, Data, CW and contests (eventually!). I don't plan on taking it mobile/ portable so it can be as big and heavy as a refrigerator for all i care as long as it does the job.

The FT-DX3000 looks like it can do everything I want and is at the top end of my budget. What do the owners out there think of it?

Can anybody suggest a better alternative for the money?

A friend has suggested the Elecraft K3 is a worthy adversary.

Submitted November 24, 2014 at 06:02PM by spidler_man http://ift.tt/15dwBt1 amateurradio