Base antenna

[Lost Ram]

You are better off taking the coax off that g5rv and make it a doublet with just the ladder line, balun, and a tuner.

[nk14zp]

You are better off taking the coax off that g5rv and make it a doublet with just the ladder line, balun, and a tuner.

Even better is a doublet and a link coupled balanced tuner. Some day I plan on building one lol.

[Lost Ram]

Yes, there are many DIY home brew plans out there for those. I use now use my MFJ 989D and LDG 1000PRO2. I have not built a tuner yet. I refurb some tube amps and update them from time to time. My latest is a Swan Mark 1. In short, its based on the AL82. I got the that giant HV transformer from Ameritron to fit in it!!! Got all my Harbach stuff in and soldered. I have went with separate transformers for the 90V bias/key circuit and 5V for the filament. So three transformers in all. I had to extend the bottom to make room for the smaller transformers and harbach items. This should easily get me legal limit without driving it to hard.

[nk14zp]

What I would like to do is build the tuner and ladder line out of some 1/2" hard line I have. Fortunately my home brew amp is in a 30" tall 19" rack. Makes all kind of room for dedicated transformers. Last mod was an old school soft start with a heat light in series with the HV deck which is two microwave transformers configured as a center tap transformer. Close to the limit with 60w drive 2700ish plate v cathode driven pair of 4-400 tubes. Tubes are a or c or a combo. Got a few of each.

[nk14zp]

All that feeds a mfj962d into 300 ohm flatline up about 30ft to a dipole as long as I could make it. Or into a 3el tribander.

[Lost Ram]

I got a couple of those 4-400's, they are much harder to drive then the 3-400 or 3-500 tubes. How much filament voltage are you using with them, and are you using a bifilar or trifilar coil to feed it. I only have about 2500V feed to that amp with a single tube.
I have tried the the 300 ohm and never had any good luck with multi band antennas, the 450 is Ok but I really like the 600 ohm, that's my go to. I have also wondered about some home brew wide ladder line with some coax as well, never got to it yet as you can get 600 ohm pretty cheap in wire from trueLadderLine. I have taken all my dipoles down, a couple years ago and built loops since. I turned my double sized g5rv into a 450 foot loop by adding a bunch of wire to it, of course I made it a doublet before the loop upgrade.

[nk14zp]

Not sure. The amp is something I bought non working and I built a new high voltage supply among other things to get it working lol. Near as I can tell from searching the lower drive is due to the cathode drive.

[nk14zp]

And yes the 300 is crap. It's raining and the auto tune in the 746 cant tune on 40 but if it's dry it's fine.

[nk14zp]

And in the end I would like to build mine into a loop. For cost tho you can't beat a doublet.

[nk14zp]

I got a couple of those 4-400's, they are much harder to drive then the 3-400 or 3-500 tubes. How much filament voltage are you using with them, and are you using a bifilar or trifilar coil to feed it. I only have about 2500V feed to that amp with a single tube.
I have tried the the 300 ohm and never had any good luck with multi band antennas, the 450 is Ok but I really like the 600 ohm, that's my go to. I have also wondered about some home brew wide ladder line with some coax as well, never got to it yet as you can get 600 ohm pretty cheap in wire from trueLadderLine. I have taken all my dipoles down, a couple years ago and built loops since. I turned my double sized g5rv into a 450 foot loop by adding a bunch of wire to it, of course I made it a doublet before the loop upgrade.

Best way to put it is my amp is not grounded grid but grid driven.