Tag: Radio shack

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A new tuner, and progress toward a new shack

For months now I’ve been struggling with my horizontal loop antenna. It’ not cut to exact resonance, it’s too low to suit me, yadda yadda – but it’s what I have right now. I have it connected (via about 50′ of low-loss LMR-400 coax) to an ancient LDG RT-100 remote auto tuner, but that tuner has struggled and largely failed to find a suitable match on nearly any band. Most of the time it only gets down to 2:1 or 3:1, so I use the rig’s internal tuner to make up the difference. My tuning process on band or large frequency changes is:

  • Disable the rig’s tuner
  • Press and hold the TUNE button on the remote keypad, assuming I’m using the FT-1000
  • Press the TUNE button on the RC-11 remote box
  • Wait for that to finish tuning
  • Release the TUNE button
  • Turn on the rig’s tuner and wait for it to find a match

After a long bout of planning to move the RT-11 closer to the feedpoint, looking for a later RT-600, rejecting the idea of several other remote tuners because they’re really not designed for balanced antennas, and deciding not to buy an RT-100 for various reasons, I decided to try a completely different approach just to see what happens. I pulled the trigger on a used LDG AT-600Pro. It’s a desktop tuner rated for 600W, with an A/B antenna switch built in as well. My plan is ti use that, remove the RT-11 from outside the house, and replace it with a good common-mode choke.

The tuner arrived yesterday, and I set it up just to see how it works. I haven’t de-cabled the RT-11 yet, so I put it in by pass mode for now. To my delight, the RT-600 has no trouble matching the antenna to 1.5:1 SWR or batter on any band I tried from 80 through 10 meters. No using the FT-1000’s tuner, and the AT-600Pro remembers the settings by frequency, so after switching bands it generally tunes in a fraction of a second. It’s almost effortless. I have a lightning arrestor arriving tomorrow that I can use to bridge the two coax runs and get the RT-11 out of the picture, and I’ll wind a common-mode choke from the excess LMR-400 and a stack of FT240-31 toroids I have coming.

I’m utterly thrilled that the AT-600Pro does so well. Now I can run the full 200W of output power on the FT-1000MP Mark V if I want to. Using gthe SB-101 or HW-16 will be easier – I can tune them into a dummy load and let the tuner do the heavy lifting there. I can only conclude that the RT-11 is crippled. I thought it was dead back in 2005 or ’06 hen it stopped working with the flagpole I was trying to use. hen I resurrected it, it seemed to work OK… but I suspect it’s got some sort of internal damage. Maybe a bad relay, maybe a stuck or dead driver line, I don’t know. Doesn’t matter; I can junk it with a clear conscience.

On another front, this morning I finished building the new run of shelves that I’m hoping will be enough for all the storage I need in the workshop. I’m clearing out some old junk, and the new shelves are much stronger and aren’t sagging (and won’t sag, either). The idea is to empty out the shelves currently taking up part of the 10′ of wall space I plan to use for the new ham shack, then move my large Ikea Galant desk from my old office upstairs down to the shack. That will give me a 110″ long, 31.25″ deep operating desk, with an “L” on the left end that’s 47″ by roughly 23.5″. I’ll have a substantial shelf overhead for the network equipment and to suspend a pair of monitors. I should have plenty of room for all of the station equipment without much stacking. I’m really looking forward to being able to have the FT-1000, SB-101, and HW-16 stations all set up and easily accessible. The biggest challenge will be keeping the cabling from turning into a rat’s nest of tangles. I need to give that some thought.

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It’s always something…

The other day I took the TS-850 apart, once again. For whatever reason (more about that later), I was only getting about 50W output on any band in CW mode. I did the ALC adjustments and got it stable at 100W where it should be… and along the way, figured out that it may have been “operator headspace” all along. There’s a CAR (carrier) control that I was suing to set the power, and also a “PWR” (power level) control that, honestly, I’d forgotten was there. I may have had it set to a lower level. Who knows? It’s working now.

I’d had to disassemble a substantial part of the “shack” to get the TS-850 set up on the bench. I had to un-cable the radio, pull the power supply, then unhook the Heathkit HM-102 power/SWR meter and the dummy load. In order to do that, I had to de-cable and move the Heathkit SB-101 and its companion SB-600 speaker cabinet with the speaker and power supply. Those sit on a shelf that I built that sits over the top of the TS-850 and some other gear. It really is kind of a major operation to take something out of the operating position desk, which is something I hope to remedy sooner or later with a bigger, roomier desk.

I got everything done – the power output back up to 100W and I re-installed the TCXO that I’d pulled for some reason a few months ago. I buttoned everything back up and spent the better part of an hour getting all of the gear re-installed and cabled. While I had it all apart, I decided to re-do the cabling. I have the antenna and the dummy load on an A/B coax switch, the input of which is connected to the HM-102, which is itself connected to the SB-610 station monitor. In order to switch from one rig to another I had to un-screw that rig’s antenna coax at the input of the SB-610, and connect the other’s coax. I decided to install the MFJ 6-way coax switch to all of the radios, and connect that tot he SB-610 to make it quick and easy to switch rigs. I wall mounted both coax switches and got everything cabled up, double-checking the connections as I went.

That evening I wanted to try some CW contacts with the SB-101. After tuning into the dummy load, I switched to the antenna and called CQ several times. I could hear a few other stations up and down a couple kHz from where I was, but I had no replies. I decided to switch to the TS-850, so just flipped the 6-way switch to position 1 and tried transmitting. The Kenwood showed no RF out – none. Even with the CAR and PWR turned to the max settings, nothing at all. Somewhat discouraged and more than a little irritated, I shut everything off and went upstairs.

The more I thought about it, the less convinced I was that both rigs had failed at the same time. I decided that I must have messed up the coax cabling, or had a bad cable. I went back down and did some troubleshooting. Starting with just the dummy load on a short coax jumper, I tested the TS-850 – full power out, no problem at all. I then went through the whole chain, connecting the dummy load at each junction and testing for power output. The 6-way coax switch tested good. Then the SB-600 – good. Then the HM-102 – good. Then the 2-way coax switch – Nope! No output.

That switch, an old MFJ-1702 that I’d picked up use years ago, has failed. THere’s nothing apparently wrong with it mechanically, I took it apart and checked for broken, corroded, or misaligned parts. It tests fine with an Ohm meter, no shorts or opens in either position. It does not, however, work with either radio in position A (the antenna) and intermittently fails in position B (dummy load).

Given its age and all, I decided not to try and troubleshoot or fix it. It’s going into the trash, and I’ll replace it with a good quality Diamond CX210A. It’s more expensive than the many options I see from Diamond, Opek, and many others including a slew of no-name Chinesium garbage that all look identical to the MFJ I’m replacing. In the mean time, I’ve connected the antenna coax directly to the HM-102.

Oh, and the reason for the low output on the TS-850? I’m honestly not sure. I suspect, however, that I simply forgot that there is both a CAR control for the carrier level in CW, AM, and FM modes, and a PWR control that is global in nature – it works in all modes, regardless of the MIC or CAR settings. Given that the most I’ve been able to get out of the rig while working FT8 without the ALC kicking in has been between 50 and 75 W, I suspect I may have just inadvertently had the PWR control set to the point where it limited CW output to 50 W. I really don’t know for sure, but I suspect that’s the root cause. Hey, at least I discovered the failed switch now rather than having it intermittently fail over some period of time and potentially cause more problems.