| Author |
Message |
    
Bob_p
Intermediate Member
Username: Bob_p
Post Number: 298
Registered: 7-2004
| | Posted on Thursday, September 02, 2004 - 9:00 pm: | 
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I was wondering if anyone knows anything about this dummy load?
Thanks in advance
Bob |
Bc910
Intermediate Member
Username: Bc910
Post Number: 150
Registered: 7-2004
| | Posted on Thursday, September 02, 2004 - 9:50 pm: |
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I found this from someone selling one on an auction site;
"100 watt 50 ohm load is in great condition and is good up to 1 GHz with a VSWR of 1.1 to 1. It is fitted with an N male connector and measures 3 x 3 x 7 inches long"
That seems to be the description that other web sites are giving too. My only problem is the N connector, I would prefer an SO-239 myself but...
All I know is there are 2K dummys for about 70 bucks out there and I could get a 300 watt dummy for 40 bucks, so if you are trying to buy it then you should probably make sure the price is right. Just my 1 cent again
BC |
Bob_p
Intermediate Member
Username: Bob_p
Post Number: 299
Registered: 7-2004
| | Posted on Thursday, September 02, 2004 - 10:06 pm: |
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Thanks Bc910 I was looking at the same one. Copper was selling a PDC dummy load but not anymore. THanks for the info, I just need to confirm my SWR and really don't want to end up putting a bunch of money into something I might use once.
73
Bob |
Bob_p
Intermediate Member
Username: Bob_p
Post Number: 300
Registered: 7-2004
| | Posted on Friday, September 03, 2004 - 1:13 pm: |
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As far as the n connector goes a double barrel connector would take care of that wouldn't it?
Thanks in adavance
Bob |
Bc910
Intermediate Member
Username: Bc910
Post Number: 159
Registered: 7-2004
| | Posted on Friday, September 03, 2004 - 9:57 pm: |
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I think so, just a bit of an annoyence
BC |
Bob_p
Intermediate Member
Username: Bob_p
Post Number: 303
Registered: 7-2004
| | Posted on Friday, September 03, 2004 - 10:11 pm: |
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Bc910 I couldn't find a dummy load except the oil can type for a decent price so I hope this works out. I did get a DL-100 too just in case. But both are rated at 100 watts. I would like to have at least a 300 dummy load, but the dead key here is 30 watts low power and high power is 100 watts, so I should be able to get an accurate swr reading out of my next meter shouldn't without too much pain. |
Tech548
Moderator
Username: Tech548
Post Number: 276
Registered: 5-2004
| | Posted on Friday, September 03, 2004 - 10:34 pm: |
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Bob
I believe Rat Shack still sells the adaptor you would need for that Load.
Out of curiousity, what did you mean when you said, "I just need to confirm my SWR". You kinda lost me on that one.
Another thing you should keep in mind is that the information that was advertized in reference to the Loads' SWR operating range. What the tag on the Load says and what the Loads actual SWR is today can be two different things.
What I'm trying to explain here is the fact that many Dummyloads end up with a SWR reading higher than what it was when it was first built. I have seen many Loads that had a reading of 1.5 and above. And the reason for this is usually from abuse. Once the resistors inside the load have been overheated to the point of burning, the accuracy of the Load diminishes.
Put another way, the higher the SWR reading on the Load, the higher the RF Power reading will be on the meter. Pretty much like an antenna. As the SWR goes up, so does the RF Power reading. If you have a flat SWR on both your antenna and Dummyload, the reading you see on your power meter will usually be the same.
The only way you can tell if it's accurate or not is by putting your SWR meter between your radio and the Load. If the SWR reads 'flat', then you more than likely have a good one. If it's reading a 1.5 or higher, then somewhere in its life it has been overheated.
Just remember, 'TRUE RF POWER' output can ONLY be read into a 'Flat' SWR. It doesn't take long to screw up a good resistor-type Dummyload when heavy RF power is hammered into them.
I'm not trying to scare you out of bidding on this Dummyload. But I think you should be aware that most radio operators keep their Loads around as long as the SWR on them remains "LOW". The higher the SWR is on a given Load, the more in-accurate the RF Power readings you will have.
One more time now. In order to have accurate RF Power readings, the lower the SWR has to be. And that applies to both Dummyloads and Antennas.
Jeff
Tech548 |
Bob_p
Intermediate Member
Username: Bob_p
Post Number: 305
Registered: 7-2004
| | Posted on Saturday, September 04, 2004 - 12:29 am: |
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Jeff I had the problem with the Dosy meters reading my SWR higher than my other meters. I have about 5 in all some are junk, but others are decent. Where they all said I was about 1.2.1 or maybe slightly lower on the I-Max on the regular 40 each of the three Dosy meters I bought read differently. One said it was 1.5.1 another about 1.7.1. and the last said about 2.0.1. So I placed a post and was told the only way to check the SWR on a meter was to put it on a Dummy Load and check it there, and someone lese suggested the other meters could be wrong. I want to add that one of the meter was the PDC 600 and another was a brand new R.S. SWR Watt meter both read 1.2.1 at 27.385 and 1.4.1 at 28.500. It just seemed too strange all the other meters read about the same and the Dosy meters all read high. So I thought I would comply and get a dummy load and check the SWR. Anyway I bought a new 100 watt Dummy Load too. I just don't have much room in my shack, it's over crowded as it is with equipment.
Thanks for taking the time as always
73
Bob
-----------------
You're very welcome.
Jeff. |
Bc910
Intermediate Member
Username: Bc910
Post Number: 161
Registered: 7-2004
| | Posted on Saturday, September 04, 2004 - 10:54 am: |
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Trust r.s.! I have had nothing but good luck with those meters considering the price and avalability! My old Dosy read 1.5:1 with absolutely no coax or antenna hooked up  it read 3:1 with a well matched antenna hooked up and 1:1 with a direct short in the antenna Dosy, for some reason stinks in my opinion
BC |
Bob_p
Intermediate Member
Username: Bob_p
Post Number: 307
Registered: 7-2004
| | Posted on Saturday, September 04, 2004 - 12:40 pm: |
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BC I agree 100 percent. my friends SWR is nearly 2.0.2 and the Dosy read a flat SWR over there. I have a great match around the regular 40 they read it was less than perfect at best. and at 29.900 where I have a high SWR the Dosy was showing I was flat. I'm nervous about buying that PDC 700 after this. I took the Radio Shack SWR Powqer meter back because my wife said I couldn't have both, but really liked it. the PEP on SSB read about the same as my PDC 600 and the Dead Key was exactly the same. The Dosy meters all read differently. |
