ARRL

WA2P

Joined: Sat, Apr 4th 1998, 00:00 Roles: N/A Moderates: N/A

Latest Topics

Topic Created Posts Views Last Activity
Using relays to switch rig coax cables to common antenna coax Dec 1st, 02:20 4 42 4 days ago
13.8 volt power supply recommendations Mar 20th 2013, 03:19 5 2,437 on 12/3/14
Transistor switch using negative base voltage Jan 2nd 2013, 04:43 10 2,015 on 3/1/13

Latest Posts

Topic Author Posted On
Using relays to switch rig coax cables to common antenna coax WA2P 4 days, 13 hours ago
Hi Martin, I would be operating HF; two of the rigs put out 100 watts, and the third, an old HT-32, puts out less. The antennas are 50 ohm, and have SWR values in the neighborhood of 1.2 to 1.3. Hot switching is out of the question; that's asking for way too much trouble!

Pat - WA2P
Using relays to switch rig coax cables to common antenna coax WA2P 4 days, 16 hours ago
Hi, I'm working on a station accessory that will move the cw keyer, headphones, and station speaker between three rigs. The coax from each rig must be switched also to a common antenna coax. I'm planning to use SPDT relays to handle the coax switching. Energizing the selected rig's relay would hook the rig to the antenna, and the other rig's relays would ground their coax cables through the normally closed contact. My question is how much of a gap between the relay contacts is needed to protect the rigs with grounded coax lines? Would small open frame relays be adequate? Thanks for any suggestions. Pat - WA2P
13.8 volt power supply recommendations WA2P on 20/3/13
Hello all,
I will be purchasing a Yaesu FTdx3000 transceiver soon, and will be needing a 13.8 volt power supply. I've been looking for a suitable supply, but so far haven't found any with really good reviews. I would prefer a linear supply, and would appreciate the names of companies I could look at. Specific model names would be great as well. Thanks for any suggestions.
Pat Ciferri (WA2P)
Transistor switch using negative base voltage WA2P on 3/1/13
Thanks, thats the most promising lead I've seen. Maybe the -49 volt value isn't as sacred as the manual suggests.

There's one other symptom I forgot to mention before. At one point, I removed ALL of the tubes except the finals and the two power supply rectifiers and the voltage regulator 0A2. The finals STILL glowed as orange as before! Of course, increasing the voltage with the bias adjustment pot made the glow disapear. Maybe it needs to be neutralized...

Pat (WA2P)
Transistor switch using negative base voltage WA2P on 3/1/13
I wish this was only a cosmetic change to reduce power consumption. Unfortunately, the original issue is that when the rig is turned on, no matter if in standby, operate, CW, SSB, or AM, the finals glow orange all the time. The rig transmits fine, it's just that the finals are going to fail if something isn't done to cut them off. If the idling current was not so high and the tubes wouldn't overheat, I wouldn't worry about it.

I've posted to the Hallicrafters Users Group forums, and the consensus was that the bias should be more negative when not transmitting. That's led me to searching for a bias modification solution since the finals will fail if nothing is done.

Thanks for everyone's input, I appreciate it. I'll check out the AM forum next. As an aside, if anyone would like the "joy" of looking at the rig and is within reasonable driving distance from Poughkeepsie, I'd like to hear from you... HI

Thanks - Pat (WA2P)

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