ToddDubya
NES Member
This is for the 25' whip, but he shows how he calculated the coil to use the whip on 40m.
View: https://www.youtube.com/watch?v=I6sgg5vA_J0
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What did you do in the shack today?
- Thread starter CatSnoutSoup
- Start date
View: https://www.youtube.com/watch?v=I6sgg5vA_J0
UJay
NES Member
Getting ready for Jan VHF this weekend -- took down 5el 10m yagi and put up 5el 6m yagi, long boom yagis for 222 and 432 and 2m yagi.
The tower is 20' so not competitive, but will give out some points to whomever hears us.
UJay
The tower is 20' so not competitive, but will give out some points to whomever hears us.
UJay
ToddDubya
NES Member
I got the wires tested to see if I could use my dipole wires as verticals and 20m was brilliant and 30m is just okay, but definitely useable. Weather permitting maybe I'll get out tomorrow for a bit.
I also got some barrel connectors with pigtails today, and made a power cable for the new Venus rig. I ordered them from somewhere west of Boston on the 10th and they just got here today. Go figure.
After that my buddy stopped by and I gave him one of the PowerPole/Wago adapters and his 6m halo antenna, and lent him a battery for winter field day. He gave me some coax jumpers, another barrel/pigtail cable, and a Yaesu data cable that I think goes with the 8x7 line.
I left the FM radios on all day in case anyone nearby was working VHF+ on FM. I heard one guy all day, and he was just calling for someone specific. Oh well.
I also got some barrel connectors with pigtails today, and made a power cable for the new Venus rig. I ordered them from somewhere west of Boston on the 10th and they just got here today. Go figure.
After that my buddy stopped by and I gave him one of the PowerPole/Wago adapters and his 6m halo antenna, and lent him a battery for winter field day. He gave me some coax jumpers, another barrel/pigtail cable, and a Yaesu data cable that I think goes with the 8x7 line.
I left the FM radios on all day in case anyone nearby was working VHF+ on FM. I heard one guy all day, and he was just calling for someone specific. Oh well.
CatSnoutSoup
NES Member
Did an LoTW update tonight and noticed that the logs from last spring's 3G0YA Easter Island DX-peditions had been uploaded.
They confirmed for me 10m SSB, 15m CW, 20m FT8, 40m CW, and 40m FT8.
Prior to this I only had the island confirmed on 20m CW and RTTY from two previous DX-peditions in 2009 and 2011
They confirmed for me 10m SSB, 15m CW, 20m FT8, 40m CW, and 40m FT8.
Prior to this I only had the island confirmed on 20m CW and RTTY from two previous DX-peditions in 2009 and 2011
ToddDubya
NES Member
I put the 20m version on the air today with the Venus SW-3B. It was far easier to setup/take down than the dipole equivalent. The (power output meter on the ) radio still implied the SWR wasn't very good, but I went with it. I got decent SNR reports from the Reverse Beacon. My QSO range was pretty much as far west as the Mississippi, and I picked up one DX station in Slovenia.
Overall I was pleased with the radio. I had a couple of weak stations that I normally would not try to copy unless I was hard up for contacts. I just leaned in and could copy everything. If I didn't know any better, I'd say they were below zero on the S-meter. Aside from being light I had no trouble copying them.
Shark_Cage
NES Member
My middle guy (18) needs his own room so our office needs to move. That also means my most of my shack needs to go into storage. Here is most of it before I wrap them up.
ToddDubya
NES Member
My buddy is working the VHF contest today and couldn't get anyone on 903 or 1296. So I offered to setup in a spare bedroom and see what we could make happen. I forget what he's running for power but I think the transverter I'm using puts out 0.5w on 903MHz. He could copy me, but I think he was being generous. I had him a solid 57-58. He's not too far away, maybe 6-7 miles, but there's a hill between us. Too bad we're in the same grid square. Fortunately I had a nice clear shot in his direction.
I searched and searched for info on this transverter. It's a Downeast Microwave 903-144 if anyone knows where I can find a manual or something. All I found was a page that listed all of their equipment/prices, but all the links are broken.
I searched and searched for info on this transverter. It's a Downeast Microwave 903-144 if anyone knows where I can find a manual or something. All I found was a page that listed all of their equipment/prices, but all the links are broken.
ToddDubya
NES Member
This sounds like a good opportunity to get your portable ops game going.
UJay
NES Member
Had fun in the VHF as a multi-op with a buddy.
Contest: ARRLVHFJAN
Band Mode QSOs Pts Grd Pt/Q
50 FT8 49 49 11 1.0
50 USB 1 1 0 1.0
144 FT8 25 25 8 1.0
144 USB 1 1 0 1.0
222 FT4 1 2 1 2.0
222 FT8 4 8 1 2.0
222 USB 1 2 0 2.0
420 FT8 2 4 2 2.0
Total Both 84 92 23 1.1
Score: 2,116
No higher bands since we did not chuck the antennas up.
@ToddDubya the DEMI manuals are still on the site, and Q5 Signal has the business now https://www.downeastmicrowave.com/articles.asp?ID=252
UJay
Contest: ARRLVHFJAN
Band Mode QSOs Pts Grd Pt/Q
50 FT8 49 49 11 1.0
50 USB 1 1 0 1.0
144 FT8 25 25 8 1.0
144 USB 1 1 0 1.0
222 FT4 1 2 1 2.0
222 FT8 4 8 1 2.0
222 USB 1 2 0 2.0
420 FT8 2 4 2 2.0
Total Both 84 92 23 1.1
Score: 2,116
No higher bands since we did not chuck the antennas up.
@ToddDubya the DEMI manuals are still on the site, and Q5 Signal has the business now https://www.downeastmicrowave.com/articles.asp?ID=252
UJay
ToddDubya
NES Member
Thanks, I had looked and didn't see it. But the kit manual should tell me what I wanted to know.
I heard a few guys on simplex yesterday talking about how they couldn't find many people on CW/SSB but there was a lot of FT8 activity. They sounded pretty disappointed about it.
UJay
NES Member
Yeah man... All of the VHF guys... But it is so easy and mindless that most gravitated towards FT8. For QSOs, you can see who is on the band from what others are working... I operated my station remote == way easy with FT8 vs other modes..... Not defending it, it just makes sense and easy for new hams to get involved over other modes (If u have a PC) .
Now, tearing all these antennas down and the temp tower so the last trees can be removed before real tower goes up.
UJay
ToddDubya
NES Member
My buddy has been trying to get me into VHF+ stuff (hence the 903 transverter and yagi). I'd have to go portable to have any real chance, and it's not worth the effort to me if it's mostly FT8. But he does the activity nights which could be fun. And I think there's a 2m SSB net in the mornings that I could probably hear only. They're a little far for what I could do.
ToddDubya
NES Member
After a whirlwind trip to get here from fire country California, I got the N6ARA Mini SWR meter kit I had ordered. It has one toroid to wind so I thought I'd just do that tonight. An hour and a half later it was all done. It's no cross needle meter, but it has LEDs that indicate FWD, 1:1, 2:1, and 3:1 to give you a ballpark of SWR when your radio doesn't have a meter. It handles 5w max, and I built mine for 15-40m. It was a pretty simple build, and would have been much quicker if I hadn't kept dropping it on the floor.
Most kits include a schematic but this one didn't. I'm curious how it works with only one transformer. All the other designs I've seen use two. My theory is that it's not "measuring" forward power, it's just indicating the presence of forward power.
Stock photo, but it looks pretty much like this minus the band indication on the cover.
Most kits include a schematic but this one didn't. I'm curious how it works with only one transformer. All the other designs I've seen use two. My theory is that it's not "measuring" forward power, it's just indicating the presence of forward power.
Stock photo, but it looks pretty much like this minus the band indication on the cover.
UJay
NES Member
TDub, Is it measuring forward power or only reflected/SWR? Maybe that only requires a single xformer.
Is this something that you would leave in-line or get a reading and yank it out? Might contribute to losses and at QRP power levels...
UJay
ToddDubya
NES Member
Yeah, that's what I'm thinking. Probably the only "measurement" is reflected power, and the FWD indicator is just "some RF is going out".
This is something I'd use to verify a known good antenna then yank back out. I've had times where things seemed off, and I had no way to know if something was wrong. So my choices were to tear down and go home or trust that it was okay enough and keep going. Basically I'll use it as a crude antenna analyzer.
Haha "TDub". I had that nickname many moons ago. I don't even remember who it was that used it. Probably high school. I had one friend who called me Todd Dubya during the early George Dubya years, which is where my username came from. I wasn't even political back then; it was just funny.
ToddDubya
NES Member
This got me thinking, now that I "discovered" using my dipole as a vertical, what about adding coils to get extra bands? I'd like a 20/30/40m antenna to use with a couple radios.
While I was poring over this last night I came up with the idea of an off-center fed vertical, where I'd use a coil to lengthen the vertical, and use a raised counterpoise as the "short" leg of the antenna. This is a little more complex because of the 4:1, so it'll take some more thinking.
That's similar to a setup a guy had where he had an attic dipole with one leg a ham stick and the other leg a wire.
ToddDubya
NES Member
Welp, I hiked half an hour out to my favorite Appalachian Trail shelter for some radio today. It was a balmy 21 degrees when I started, but honestly not too bad because it was calm and sunny. I got all setup and got to try out my mini SWR doodad. It read 3:1 or greater using my 20m dipole as a vertical. I checked the wires/coax and everything looked fine. I reconfigured it as an inverted vee, a setup I've used countless times, still 3:1 or worse. So I packed it all back up, hiked out just about in the dark, and headed for home. It was 17 when I got back to the car.
I don't know what the hell is going on. I tested this exact setup in the yard a week ago and it was barely over 1:1. But the radio folds back the power, and now the SWR meter says it's rubbish too. I guess I have to set up in the yard again, try it with the meter and with an antenna analyzer and see WTF is going on.
I thought maybe my 1:1 choke could be the problem, but I at least confirmed continuity from the BNC connector to the terminals, and no continuity between the terminals. Maybe the coax? It's the same coax I used to test it last week, too. The only other thing I can think of is that maybe the radio's output impedance isn't 50 ohms. I don't know how that could happen, but it's a new radio to me.
Just tried the radio, through the SWR meter into a dummy load: 1:1. I guess that's good.
I don't know what the hell is going on. I tested this exact setup in the yard a week ago and it was barely over 1:1. But the radio folds back the power, and now the SWR meter says it's rubbish too. I guess I have to set up in the yard again, try it with the meter and with an antenna analyzer and see WTF is going on.
I thought maybe my 1:1 choke could be the problem, but I at least confirmed continuity from the BNC connector to the terminals, and no continuity between the terminals. Maybe the coax? It's the same coax I used to test it last week, too. The only other thing I can think of is that maybe the radio's output impedance isn't 50 ohms. I don't know how that could happen, but it's a new radio to me.
Just tried the radio, through the SWR meter into a dummy load: 1:1. I guess that's good.
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Parker Duofold
NES Member
The weather has finally warmed up here in South Carolina so my project for the day was to work on my OCF inverted vee, The dimensions I built it to I got from the Balun Designs website. They are based on some antenna modeling done by Walter Lau KK1CW (SK). This design calls for the overall length to be 135.85 feet. The long leg is 96.6 feet and the short leg is 39.2 feet. With those dimension the best I could get the SWR on 40 meters was about 3.5:1 . This just wasn't working because if the match isn't good on 40M then the other harmonically related bands will not be good either.
I changed the dimension of the antenna to 90 feet on the long side and 45 feet on the short side - this is the classic 66%/33% OCF dipole design. This new configuration gives me an SWR of 1.7:1 on 40 meters and the other bands are reasonable also. I think the antenna is still a bit long. Years ago, I read somewhere that in a vee configuration the classic dipole measurements should be cut a bit shorter. The center of the antenna is up approximately 50 feet.
I changed the dimension of the antenna to 90 feet on the long side and 45 feet on the short side - this is the classic 66%/33% OCF dipole design. This new configuration gives me an SWR of 1.7:1 on 40 meters and the other bands are reasonable also. I think the antenna is still a bit long. Years ago, I read somewhere that in a vee configuration the classic dipole measurements should be cut a bit shorter. The center of the antenna is up approximately 50 feet.
ToddDubya
NES Member
Yes, inverted vee antennas should be physically shorter than flat top dipoles. How much depends on the angle. I'm glad to hear you're getting it back up and running.
I can't vouch for this calculator, but it shows the difference in lengths between the inverted vee and dipole.
I can't vouch for this calculator, but it shows the difference in lengths between the inverted vee and dipole.
