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61
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eHam Forums / VHF / UHF / TR6 VS SB110
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on: May 05, 2012, 10:59:17 AM
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I'd like to get into 6meters, likely with a dedicated, older rig. I've got a Drake 4 line now, that I have spent some time with getting right and also making contacts on HF. THe tr6 lets me use my AC4 power supply, a slight advantage to the drake. But, now I hear the Heath has quite a bit better Rx sens on 6. Any first hand advice out there? My other issue is actually finding a good, older rig, not a lot of available rigs, apparently.
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62
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eHam Forums / Antennas and Towers and more / RE: Why Are PL259/SO-239 Connectors Preferred for HF Instead of N- Connectors ??
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on: April 28, 2012, 05:16:03 PM
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For power in general, a N will handle more but a lot of that is due to the fact that the overall connector parts are heavier.
I read that to mean the N will handle more power than a BNC. So, yes, I agree with this argument. In a nutshell; for HF applications, the UHF will handle more current, and more voltage. The weatherproofness hat goes to the type N. For UHF and above, certainly 800 and above, the type N is generally more favored due to its constant Z design. On a tower, one could argue the UHF is a bit easer to deal with, since there are no small parts to drop/lose. At least the conventional type N has seals, a small center tip and still needs a soldering system. |
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64
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eHam Forums / Elmers / RE: Measuring Complex Impedance of a Toroid
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on: April 25, 2012, 08:34:06 AM
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If I read this correctly, you are measuring the real (resistive) component of a two turn winding on a core. Well, two turns will have very low R component, not much higher than the ohmic R at DC. What is the reactive component (L)?
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65
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eHam Forums / Boat Anchors / RE: Too much RF gain
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on: April 24, 2012, 12:15:36 PM
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Several ways of "recapping" the electrolytics. I know of no new, factory built multi-sections out there. For my Drake 4-line, I removed the twist lock cans and cut, with a dremel cut-off wheel, the can off, just above the bend at the base. Remove and toss the guts. I bought 105deg caps from Mouser and drilled small holes thru the base phenolic that could pass the small leads, which then were soldered to the lugs. The top was put back on using JB weld epoxy and masking tape to keep things looking good. Sometimes using lead insulation, epoxy inside the can as required.
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66
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eHam Forums / Boat Anchors / RE: Who has tubes?
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on: April 20, 2012, 07:07:18 PM
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Me too. I've been scrounging places to find spares for my r4a/t4x. I take it you have a later R4, since i use the 12BZ6, and the later versions use the 6BZ6.
Ebay has been good in this regard. Also, investigate craigslist, since lots of TV tube caddies come up locally and you can sometimes pick out just what you want.
Yes, the 6HS6 prices are out of line. I could use a spare also. One more thing; just last week I noticed that my S-meter had some warm up drift during the first 5 minutes, with about 6 S units of downward drift. It was a gassy 12BA6, that passed a TV6 tester.
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67
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eHam Forums / Antennas and Towers and more / RE: What would you suggest for lightning and EMF protection
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on: April 16, 2012, 07:02:27 PM
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I'm getting ready to put up a new Buckmaster 7 band dipole. The last one was zapped by lightning. The feed cable will be LMR400 Direct Burial as I have reloacated my dipole further from my house. I'm thinking of using ALPHA-DELTA ATT3G50N 200W TO 3 GHZ SURGE PROTECTOR N in the feed cable and grounded to the grounding rod for my electrical service. Last time I used an ICE Electronics device; however, the Alpha-Delta allows easier changing of the protective cartridge if necessary. OK, won't hurt.
Additionally I am thinking of a Times Microwave - Ground Kit for LMR-400 Mfg Part #: GK-S400TT which would be strapped onto the cable and also grounded to the same grounding rod. I believe this grounding strap is normally used with antenna towers. Do you think this is a good idea to use as I described? Need a plan to get a ground strap to the electrical main ground rod. Grounding to a single ground rod is inadequate.
Lastly I am thinking of using an Alpha Delta Coax Switch Wall Mounted to a copper bar as done by KF7P Metalwerks. This way when the antenna is not in use I would disconnect the cable from the Coax switch and the feed cable into the room would still be grounded. I use the metalwerks outdoor mounted steel box that has the copper back plate. I think they are a great idea; i've got the copper plate connected thru 2" x .035 copper strap to the house entrance ground rod.
Lastly and this is probably the strangest right outside the room I use for my operations is a downspout for rain. This downspout is pure copper. I was thinking of connecting my copper grounding bar in my room to the downspout which terminats at ground level within inches of my service ground. I could easily strap it to the ground. Yeah, there is merit in getting all "flashover" objects bonded. Not sure it helps the radios that much, but if it's in the vicinity, take advantage of it. BUT, one ground rod is not near enough conductivity to ground
What parts above do you think are viable?
73
Will
KB1PXU
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68
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eHam Forums / Antennas and Towers and more / RE: Guy wires on a tiled roof
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on: April 11, 2012, 05:10:48 AM
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I would tend to discourage you from disturbing a tile roof with penetrations. I have a concrete tile roof and there are a couple of points to be made. Bob is correct about the difficulty in resealing the underlayment below the tile. It won't take more than one roofer visit to pay off a couple of Rohn tower sections that can be secured to the side of the house without violating your roof water barrier. Also, with a HF antenna just above your roof, you are tempting RFI issues with home electronics. You will be irradiating your home wiring in the attic and be closer to TV's, stereos, appliances, etc.
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70
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eHam Forums / Boat Anchors / Why triple conversion?
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on: April 06, 2012, 03:27:30 PM
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I've admired the Hammarlund receivers for decades now, never owned one. I did pick up a Drake R4A recently. So, here is the leading question. What does the triple conversion scheme do for the Hammarlund? Does it have better IM or image than the ten year newer Drake? The Drake is speced at better than 60dB. Even more to the point: Will one of the better Hammarlund's receive better under some conditions than the Drake? Obviously, the Drake is not out of the box continuous receive, and would take a bunch of crystals to make it so.
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71
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eHam Forums / Elmers / RE: using two radios so close to one another ??
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on: April 02, 2012, 02:17:02 PM
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How timely; I just got my T4X back up on the air, and I wanted to check audio before I made a QSO. I have a TS50 in the shack as well. Even with the coax off of the ts50 and the attenuator ON, there was quite significant "noise" on channel with the TS50. It went away with either the Tx on a dummy load, OR the ts50 on a dummy load. With even an open SO235, there was 60 db over S9 with some noise products heard.
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72
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eHam Forums / Elmers / RE: curious Triplett behavor
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on: March 29, 2012, 02:35:19 PM
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Lee - In about 1969, when the Navy was going with TBS movements on new and replacement switchboard meters, several of us meter mechanics got sent to a school in Dayton where we actually were trained in disassembling the movements and replacing the bands! In those days I had eyes and hands that worked a LOT better than they do today...  Well; I have a lot of respect for that work now. My past includes a bit of surface mount rework, and design, but this Triplett TBS defeated me. I tried a touch of epoxy to add weight but it surprisingly shifted zero even when the pivot was vertical. Went in a bit deeper, and bad things started to happen, sticky behavior, taunt band got out of align, more scratches on the dial, bent needle.... Oh well, a $10 lesson and I'm still amazed at how much manufacturing labor you got back in the day.. |
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73
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eHam Forums / Elmers / curious Triplett behavor
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on: March 27, 2012, 02:36:41 PM
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I've got now a fine Triplett 630HS. On its back, it reads accurately. Moved upright, the zero set is quite a bit off, but even when that is reset, now the DC volts is about 5% low. ANyone see this before?
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74
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eHam Forums / Boat Anchors / RE: Old headphone technology
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on: March 26, 2012, 07:36:47 AM
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Yes, 2000 ohms and a dynamic steel diaphragm. I drove mine from a 1T4 tube. The name might be "radio headphones". You might need to weed out several hundred stereo headsets before you find the right one!
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