| Author |
Message |
    
Wildrat
Advanced Member
Username: Wildrat
Post Number: 658
Registered: 12-2003
| | Posted on Monday, January 16, 2006 - 9:56 am: | 
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Is there anything I can do to this switch to give it better isolation between positions. For example: When I have it in the Aux position which is my paint can dummy load I still get pretty good receive, and I have had people come to the freq I am tuning on when in the Aux position to see whats going on.
Mark
CEF674 |
Marconi
Advanced Member
Username: Marconi
Post Number: 522
Registered: 11-2001
| | Posted on Monday, January 16, 2006 - 10:53 am: |
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Wildrat, I'm afraid to tell you that I have seen the same thing and that is bad. If you will look at the SO-239's on the back of the meter you will also see that the metal inside where the coax tip goes is very thin. I have found these to be a problem of bad contact also with the modern day meters that Dosy makes.
The older meters were not as bad in this regard, but I don't recall ever using one of those with an antenna switch it is either. I'm not even sure they make a switching type meter 20-30 years ago.
I do not use my Dosy meters just for that reason alone. They will leak bad. Just my opinion. |
Wildrat
Advanced Member
Username: Wildrat
Post Number: 661
Registered: 12-2003
| | Posted on Monday, January 16, 2006 - 1:26 pm: |
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I got this one back in the early 80's. I have not looked at the 239's. I guess I will now, maybe find a better connector and replace them. I notice on the description of other switches that they say something along the line of being grounded or something when a certain position is not being used. I don't know. Maybe someone else will have an idea.
Mark
CEF674 |
Tech808
Moderator
Username: Tech808
Post Number: 8982
Registered: 8-2002
| | Posted on Monday, January 16, 2006 - 1:32 pm: |
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Wildrat,
You can REPLACE the SO-239 connectors on your Dosy Antenna Switch with the the SO-239 Conectors listed below.
SO-239 HOLE PNL
Hope this helps,
Lon
Tech808
CEF808
N9OSN
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Wildrat
Advanced Member
Username: Wildrat
Post Number: 664
Registered: 12-2003
| | Posted on Monday, January 16, 2006 - 5:45 pm: |
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Lon,
I looked at the connectors. Not to be to witty, but I dont understand how changing these connectors will help the problem. Are we trying for more shielding or something?
Mark
CEF674 |
Tech808
Moderator
Username: Tech808
Post Number: 8985
Registered: 8-2002
| | Posted on Monday, January 16, 2006 - 6:39 pm: |
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Wildrat,
Since you mentioned yours is from the 80's it would not hurt to replace the SO-239's as the centers do tend to wear out and get loose over the years.
Hope this helps,
Lon
Tech808
CEF808
N9OSN |
Wildrat
Advanced Member
Username: Wildrat
Post Number: 665
Registered: 12-2003
| | Posted on Monday, January 16, 2006 - 9:14 pm: |
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gotcha
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Marconi
Advanced Member
Username: Marconi
Post Number: 524
Registered: 11-2001
| | Posted on Monday, January 16, 2006 - 10:58 pm: |
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But guys, even if you fix those connectors you still have that leaky orbital switch inside that all the RF has to go thru.
How far away was the station that hears you leaking past the dummy load? |
Wildrat
Advanced Member
Username: Wildrat
Post Number: 667
Registered: 12-2003
| | Posted on Tuesday, January 17, 2006 - 8:51 am: |
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about 10-15 miles as the rat crawls. In rat miles that's about a thousand miles. |
Marconi
Advanced Member
Username: Marconi
Post Number: 527
Registered: 11-2001
| | Posted on Tuesday, January 17, 2006 - 11:58 am: |
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If it had been on the next block, I would say forget it, but since it was 10-15 rat miles, let the rat have the thing and do without a meter and get you a good switch. It's only rat money. |
Wildrat
Advanced Member
Username: Wildrat
Post Number: 669
Registered: 12-2003
| | Posted on Tuesday, January 17, 2006 - 1:54 pm: |
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Whats a good switch, I read in a review somewhere that this was suppose to be a decent one as compared to some of the others out there. I guess there ain't nothing good anymore. It's too bad you couldn't do something to this SW. to help it out. I have ordered the same SW. pat has from MFJ but it is back order. I don't know how good that SW. is either.
Mark |
Marconi
Advanced Member
Username: Marconi
Post Number: 529
Registered: 11-2001
| | Posted on Tuesday, January 17, 2006 - 5:11 pm: |
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I just do not like that round switch they use in the Dosy, if just does not isolate signals going into it is what I have found. Their other meters, without antenna switching, are OK however.
I just think it is cheap. Dosy use to make meter that were so heavy that hooking RG8 coax was not a problem for them sitting straight on the station. But the modern versions are so lite that you almost have to use small coax jumpers.
That is when I saw the changes I referred to above. Maybe it was longer than 25 years ago. I didn't write it down. The meters still look great though. |
Hollowpoint445
Senior Member
Username: Hollowpoint445
Post Number: 1020
Registered: 6-2004
| | Posted on Wednesday, January 18, 2006 - 8:55 am: |
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Alpha Delta switches are excellent. A friend got one because his old switch leaked so much that when he switched to his his dummy load, I still got an S-3 signal from him. He replaced that switch with an Alpha Delta and I can still hear him faintly, but my needle doesn't move at all. |
Wildrat
Advanced Member
Username: Wildrat
Post Number: 677
Registered: 12-2003
| | Posted on Wednesday, January 18, 2006 - 9:06 am: |
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Finally got my switch from MFJ, been on back order since before Christmas, now to figure it out.
Mark |
Wildrat
Advanced Member
Username: Wildrat
Post Number: 678
Registered: 12-2003
| | Posted on Wednesday, January 18, 2006 - 10:46 am: |
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Pat are coming over to hook the switch up? IT's like yours MFJ-1700C
Mark |
Tech808
Moderator
Username: Tech808
Post Number: 9008
Registered: 8-2002
| | Posted on Wednesday, January 18, 2006 - 11:22 am: |
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Wildrat,
Very easy to hook up and should take you less than 10 minutes to connect everything. 
One side says ANTENNA and the other side say's TRANSMITTER.
Hook your Coax from your Antennas and Dummy Load to the Antenna side and hook the Jumpers from your radios to the TRANSMITTER side.
I even posted a picture of mine in the forum here and use different colored labels for each antenna and radio to make things easy.
And if all else fails always read the Instructions.
Lon
Tech808
CEF808
N9OSN |
Wildrat
Advanced Member
Username: Wildrat
Post Number: 679
Registered: 12-2003
| | Posted on Wednesday, January 18, 2006 - 12:23 pm: |
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yea, I know it's easy. I was just looking for different configurations. I will have to look at your pics again. I downloaded them so I could, I don't remember seeing the switch, maybe because of the embossing gun stickers. I will go look now.
Mark |
Wildrat
Advanced Member
Username: Wildrat
Post Number: 681
Registered: 12-2003
| | Posted on Wednesday, January 18, 2006 - 2:13 pm: |
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Lon your switch is different than mine in configuration. My connectors are on four sides and I also two connectors marked common.
Mark |
Tech808
Moderator
Username: Tech808
Post Number: 9010
Registered: 8-2002
| | Posted on Wednesday, January 18, 2006 - 5:43 pm: |
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Wildrat,
The ONLY difference is the location of the connectors (SO-239's) on your MFJ-1700C compaired to my MFJ-1700B.
You still have TRANSMITTER Position Control Switch with 6 Positions A/B/C/D/E/F and ANTENNA Position Control Switch with 6 Positions A/B/C/D/E/F and 2 Common SO-239 Connectors.
You will run Jumper's/Coax from the MFJ-1700C COMMON SO-239 Conectors to the SO-239 Connectors marker IN & OUT on your WM-1 SWR/WATT Meter or other SWR/WATT Meter.
Hope this helps,
Lon
Tech808
CEF808
N9OSN |
Wildrat
Advanced Member
Username: Wildrat
Post Number: 682
Registered: 12-2003
| | Posted on Wednesday, January 18, 2006 - 5:58 pm: |
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I think I like the way the 1700b is laid out more than there new 1700c configuration. It makes the coax layout a lot better, and better looking.
Mark |
