| Author |
Message |
    
Yaesujohn
New member
Username: Yaesujohn
Post Number: 3
Registered: 9-2005
| | Posted on Sunday, September 25, 2005 - 5:44 pm: | 
|
I've never heard of this, but I recently acquired an old "Stupid Scanner" antenna that does not seem to have any way to use as an omni! It has a small metal control box that doesn't look anything like the ones I remember, and the switch knob only has three positions. It's painted with the old hammer-finish style paint, and has an on-off rocker switch on top. I'm sure this is the original control box, especially since it has a couple of A/S stickers on it. I gather that this is one of the very first ever made. I found a manual online and downloaded it. It has schematics in it for the relay box and (newer-style) control box. I opened up the relay box to compare it to the schematic in the manual. According to the manual, it should default to the omni condition if no power is fed to the relay box (uses DPDT relays), however my relay box uses tubular-looking relays that are only single-pole. When the relays are not powered, there is no continuity from the center of the SO239 coax connector to any of the elements. I've comfirmed this by connecting the control box up with some jumpers, and using an ohmmeter to test for continuity. (Works normally, otherwise.) This makes no sense to me at all! First off, I've never heard of any SS that didn't work as an omni AND a beam. I always thought that was the whole idea behind the SS anyway (omni/beam all-in-one). Also, I can't imagine that A/S would design an antenna that would allow you to key down on an open coax, which is what would happen if you had the control box switched off. That makes no sense at all! I'm wondering if it would do any good to call A/S an ask them about this? I think if I could get my hands on a newer 4-wire (DPDT relay) style relay box, I could get this to work as both omni and beam like I need it to do. Does anybody have one of these? Has anybody ever dealt with an SS like this one? |
Tech833
Member
Username: Tech833
Post Number: 90
Registered: 12-2001
| | Posted on Monday, September 26, 2005 - 1:56 pm: |
|
Indeed, you got one of the first ones.
No, it is not possible to change it to a newer version, your antenna has no omni capability. Simply changing the control box won't do it. The newer versions had a matching network in the antenna hub for omni operation. |
Yaesujohn
New member
Username: Yaesujohn
Post Number: 5
Registered: 9-2005
| | Posted on Tuesday, September 27, 2005 - 4:17 am: |
|
I understand that simply changing the control box isn't going to get me the omni capability, and that's not what I was talking about. What I want to do is change the relay box on the antenna to the newer style. The newer control boxes that have the omni position give you that by simply not supplying power to any of the relays. I can do the same thing with my existing control box by just shutting off the power switch. I have the schematic which shows how the newer relay box gives all 4 modes. It also shows the matching network for the omni mode. It uses either a 9' length of coax which hangs down from the relay box alongside the mast (taped to the mast when installed), or a 9 turn coil and a 240mfd cap. If I can find the proper relays, I may just try to make my own version of the newer relay box. The schematic is pretty clear. The only thing I'm not clear on yet is the amp rating I'll need the contacts in the relays to be able to handle. |
|
