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Author Topic: Transmitting woes - Not being heard - Out Of ideas  (Read 7104 times)
KB8LOG
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Posts: 36




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« Reply #15 on: February 04, 2013, 01:34:58 PM »

Thanks everyone for the replies so far. I would have responded sooner, but I posted before going to bed last night and have been occupied here at work until now. I've made a list of points that were made and will reply to each here.

Find a local elmer: I have reached out to two people who live within the area but have not yet heard back from them. It's been a few days, so I will probably wait a bit longer before contacting others. As has been pointed out by a few of you, bringing my transceiver to another location and firing it up there would be a great test to eliminate the rig as my problem.

What kind of building am I occupying? It's an apartment with wood construction and vinyl (or some other plastic) siding. I did a bit of drilling over the weekend to check the studs because I worried that they may be metal. Fortunately they are wood. Also - it's a three story building and I am in the bottom level. I am on the end of the building as well. The patio is about 8'x8'x8', with one side open and looking out at some trees. The trees aren't exactly antenna supporting material due to loads of small branches. Plus there's quite a bit of foot traffic back there during the day, and occasionally at night.

Try a mobile setup with a 10 meter dipole: I may do this once the constant snow and wind relents and I have spare time. Good idea though.

Wattmeter/SWR bridge: I do have a watt/SWR meter. It's a MFJ-816. Nothing special, but it has worked for me. The power meter does register output when I transmit. The SWR meter, however, just started to act up over the weekend. It intermittently is inactive even when the wattmeter is working correctly. I'll probably start looking for a replacement soon, or see if I can fix it myself.

Is the transmitter transmitting? This is the question I am asking myself as well. According to the MFJ wattmeter, it is transmitting. Unfortunately I do not have any other means of checking. Though...now that I think about it, there may be something I can try. While reading up on magnetic loops I've seen mention that a fluorescent light will illuminate when brought near the loop during transmission. Though that would only indicate that the loop is radiating, it would at least show (I think) that the transmitter is doing something.

Metal sheeting under shingles, attached to insulation, etc.: I am not sure about this, and I really don't think I can find out without doing damage to the drywall, which I'd prefer not to do since I'm renting the place.

Loop on the patio: The weather here has been uncooperative with lots of gusting wind and snow. Since the Alexloop is on a tripod that won't support it well in the wind, I haven't been able to keep it out there much. Once the weather does calm while I'm at home, I will try this.

Schedule a contact: I have tried to set up a few contacts, but so far the scheduling has not worked out due to jobs.

Try listening with another receiver: I have not tried this, but you know what...I've got an old Drake receiver that I could use, assuming it's still in working order. It's been packed away for a long while. As I have never attempted to listen to myself with a rig in such close proximity to the transmitter, is there anything special I should do?

Drilling holes in the wall: A ham among hams! That made me chuckle. I had to know if the studs were metal or not. Thank goodness they're not.

SWR on loop not necessarily a good indicator of performance: I agree. When I purchased the Alexloop, I was under the assumption that my struggles were the result of using homebrew antennas. I was doing all of my antenna building with a lack of knowledge and experience. Though it was fun and I did learn quite a bit, I always doubted if my work would actually perform. In some cases it did not and further investigation revealed why. For example, I made a magnetic loop out of soft copper tubing that tuned quite well, but because all of the connections/joints were mechanical, I assume that the efficiency was likely reduced to zilch. The Alexloop seemed like a good option because I want to stick to low power, even QRP if possible, and it's easy to pack up and get out of the way. However, it's definitely not the most efficient antenna for 40 meters. Heck, according to the calculators I checked, even the magloop I made, done with no mechanical joints and added resistance, would only be about 7% efficient on 40 meters. So I totally agree with the point that low SWR doesn't necessarily mean good performance.

Compromise antenna/location: This is really the root of the problem as far as I am concerned. If it were up to me I'd have a proper fan dipole set up outside. But I don't have that luxury. Some day hopefully I will! In the meantime I'm trying to do the best I can to work with the accommodations.

Alexloop internal tuner / Am I using my own tuner: I have not used a tuner with the Alexloop because it's pretty easily done by ear, and then fine tuned with low output and adjusting the built-in tuner on the loop. In addition, as far as I know, as long as a magloop can be tuned for a band by adjusting the capacitor and/or coupling loop/gamma match, then an external tuner shouldn't be necessary. The tuner I do have is a MFJ-901B, so that is available if necessary for use with other antennas.

Does frequency displayed change on transmit? RIT or VFO A/B? These are among the first things I checked as I started investigating, and now I'm rather paranoid about keeping an eye on them. The frequency doesn't change when I am transmitting. RIT is definitely not active, though I do occasionally adjust it while listening. I am always sure to turn it off afterward. And the VFO A/B setting is always on A. I had to read the manual recently to refresh myself on that feature.

Was a tuner used when I tried using my dipole? Initially I was using the tuner. The reason was that I put this dipole together myself. I had purchased a balun for it at a hamfest a few years ago, but never put it together. I happened to have some wire handy and thought I'd give it a shot. Because I was doing all of this myself and I've never felt confident in my past antenna projects, I felt like I needed to use the tuner even though the wires were cut for 40 meters. Eventually I did remove the tuner and tried it that way. Unfortunately the location I used probably wasn't ideal. I tried two arrangements: The first was by having the balun near the transmitter and stringing the wires along the ceiling in the living room, forming a U shape. The second was to string one wire from the balun (which was in the same position as the first arrangement) further into the apartment, keeping it as straight as I could, and then running the other wire out the back door through the patio and to a tree branch. I had a good chuckle while doing that at night.

Local ham/club info: Thank you! Those names you provided aren't the same people I contacted already, so I am going to make note of them.

Mic gain: Good idea, but it shouldn't matter since I'm only doing CW work. Unless the IC-718 has some feature I'm not aware of that somehow links mic gain to CW.

Whew! Sorry for the wall of text, but I wanted to cover everything in one shot rather than a bunch of individual responses. Thanks again to everyone who has chimed in so far. I really appreciate it.
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K2OWK
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Posts: 1078




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« Reply #16 on: February 04, 2013, 02:06:35 PM »

There is a website where you can listen to your own transmission on any of three bands. Select the frequency, transmitt as you normally would and listen for your transmission. This receive station is located in Atlanta Georgia. Make sure your frequency is clear both at your QTH and the receiver in Georgia. This site will not only let you hear your transmission, but also to see it on there waterfall display. The bands available are 80, 40 and 20 meters.

This is the link,

http://www.w4ax.com

Hope this helps,

K2OWK
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K2OWK
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Posts: 1078




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« Reply #17 on: February 04, 2013, 02:21:05 PM »

Quick add to last post. This website has  four bands available 160, 80/75,40 and 20.

73s

K2OWK
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AA4PB
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Posts: 13032




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« Reply #18 on: February 04, 2013, 03:31:12 PM »

"As I have never attempted to listen to myself with a rig in such close proximity to the transmitter, is there anything special I should do?"

Just don't connect an antenna to the Drake. Connect a dummy load to it if you have one, just in case you accidentally transmit. Actually, you could transmit CW with the Drake, zero beat the signal with your transceiver, the transmit back to the Drake to ensure that your transmit frequency is close enough to be heard.

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KB8LOG
Member

Posts: 36




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« Reply #19 on: February 04, 2013, 04:27:47 PM »

Well I think the transceiver is fine, at least as far as output goes. Over the past week I've been building another magnetic loop with soldered pipe and better construction overall. This is something I have wanted to do since my previous binge of experimentation. Anyway, this evening I hooked up a variable capacitor just to see if the loop would tune as expected based on the calculations I used - so far so good there. Unfortunately the caps I have were all salvaged from old car radios, so the voltage spacing/rating isn't ideal. I was dismayed to see some arcing between the plates when I tried to transmit even at 10W. At first I was disappointed, but then I realized that this seems a good indicator that the transmitter is working. In my opinion, this new finding points to something in this apartment building being my roadblock.
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N3JJT
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Posts: 31




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« Reply #20 on: February 04, 2013, 04:58:40 PM »

Scott:  Just to check:  There is a menu setting on the IC718 that enables the TX of CW and SSB, or they can be set to RX only.  Forget what the Menu label is, but I am sure it is in the intitial menu setting.  Not your quick sets.  Worth a look.

Scott  N3JJT  GL
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N4CR
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Posts: 1702




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« Reply #21 on: February 04, 2013, 08:01:08 PM »

Getting an Elmer is good advice. If I were you (assuming you have access to a vehicle)  I would make me a simple dipole resonant on 28.4 MHz, fed with a short piece of RG-58, park my vehicle between two trees, and string up the dipole. Run the (fused) XCVR directly from the battery in the vehicle (or from an auxiliary battery) and try some portable CW or SSB field-day-type operation on a day when 10m is open.

I'd advise the same with the exception that I'd target 20 meters.
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73 de N4CR, Phil

Never believe an atom. They make up everything.
K8AXW
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Posts: 4002




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« Reply #22 on: February 04, 2013, 09:24:02 PM »

LOG:  Back in the day we used to connect a short piece of coax to the antenna terminal and terminate the other end with a light socket with the appropriate size light bulb installed. 

You might want to give this a try and see if the light bulb lights to almost maximum brilliance with keydown.  I have no idea if your foldback circuit will be involved with this test. 

If not, this will show you that you have RF output, for sure!
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W5DXP
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« Reply #23 on: February 05, 2013, 04:10:37 AM »

I'd advise the same with the exception that I'd target 20 meters.

Then he wouldn't be able to use SSB.
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AA4HA
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« Reply #24 on: February 05, 2013, 05:51:25 AM »

I was dismayed to see some arcing between the plates when I tried to transmit even at 10W. At first I was disappointed, but then I realized that this seems a good indicator that the transmitter is working.

Yea, that might get in the way of being heard. Unless you are into 1920's spark-gap transmissions.
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Ms. Tisha Hayes, AA4HA
Lookout Mountain, Alabama
KB8LOG
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Posts: 36




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« Reply #25 on: February 05, 2013, 06:38:19 AM »

I was dismayed to see some arcing between the plates when I tried to transmit even at 10W. At first I was disappointed, but then I realized that this seems a good indicator that the transmitter is working.

Yea, that might get in the way of being heard. Unless you are into 1920's spark-gap transmissions.

Haha! I know. Smiley I simply meant that it is a pretty good indication that power is going out of the transmitter. I stopped trying to transmit after I saw the arcing. Fortunately I've got a much more ideal air variable cap on the way. Hopefully it'll arrive on Saturday.
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AC2EU
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« Reply #26 on: February 05, 2013, 07:52:18 AM »

from 'LOG
Quote
I was dismayed to see some arcing between the plates when I tried to transmit even at 10W. At first I was disappointed, but then I realized that this seems a good indicator that the transmitter is working. In my opinion, this new finding points to something in this apartment building being my roadblock.

Yikes! If you keep that up, you will let the smoke out of your radio! It also sounds like you have a major mismatch issue to generate that much voltage at 10W. It takes a surprisingly high voltage to jump a small gap in air. I have used the old fashioned metal variable caps from broadcast band receivers on up to 40 watts with no arcing as long as the energy was leaving the circuit into a load.
Since you seem to enjoy home brewing antennas, invest in an antenna analyzer to test your creations rather than using your transceiver as a guinea pig. Get one that reads out complex impedance. SWR alone is too basic.

An indoor antenna is never as good as an outdoor one,  but i have a feeling that that is the least of your problems at the moment...

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K4RVN
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« Reply #27 on: February 05, 2013, 04:50:51 PM »

You need a dummy load to check the 718 output with 50 ohms impedence. Also use your watt meter and don't worry if it is not the best available. I use a radioshack on one of my transceivers, but have a fairly good one to use also by MFJ.  Borrow a dummy load or buy one as you can always find it useful over the years. Connect the watt meter to the output of the 718 without a tuner, then put the dummy load after the watt meter. Try various settings on your 718 power out and your watt meter should track fairly close. The 50 ohm dummy load eliminates checking SWR. If a 718 is putting out the set power level then you could perceive that the swr is ok without error.  In the older days hams often used a 100 watt bulb in a lamp connected to the output coax. This was because the tube transmitter with a pi network would load almost any impedance. Solid state transmitters will in general fold back the power output if the swr exceeds the specified value.
The dummy load here again eliminates that as a problem. If you do this and all looks ok, then you know it is your antenna.

Frank
« Last Edit: February 05, 2013, 04:53:12 PM by K4RVN » Logged
KB8LOG
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Posts: 36




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« Reply #28 on: February 05, 2013, 10:21:34 PM »

I realize I am getting a bit off track of my original topic here, but I think this is still working toward the goal of determining why my signal isn't getting out.

During my previous antenna experimentation binge I did purchase an antenna analyser. It's the VK5JST Aerial Analyzer. I built it and ran into an issue getting it to work correctly. At around that point I was downsized by my employer, so I had to dedicate much of my time to job hunting and set most ham stuff aside. I decided to dig the analyser out this evening and see if I could get it working. Following some reading and digging I found the problem was something I did incorrectly during the assembly process. Fortunately I was able to fix the issue rather easily.

I just hooked the analyser up to my new homebrew magnetic loop. The readings I am getting at the currently tuned resonant frequency of 7.064 MHz are resistance of 50 ohms, reactance of 0 ohms, and SWR of 1:1. I've spent the past hour or so studying what these measurements beyond simply telling me if an antenna is good or bad. I'm still trying to determine how impedance is determined as well.

Interesting stuff! Unfortunately I need to get some sleep, but I thought I'd give an update on my progress.
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W5DXP
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« Reply #29 on: February 06, 2013, 04:34:45 AM »

The readings I am getting at the currently tuned resonant frequency of 7.064 MHz are resistance of 50 ohms, reactance of 0 ohms, and SWR of 1:1.

If I set my transmit frequency to 7.064 MHz, that's the readings I would get using my Bird dummy load.Smiley Maybe it's time to build a field strength meter?

http://images.search.yahoo.com/search/images?_adv_prop=image&fr=yfp-t-701-s&va=field+strength+meter+schematic
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