I got me the Bird

[w1vtp]

Bird 8201 500 watt load, that is.  I brought it into the shop and here are the results of my preliminary test.  Looks good.

OK, OK, I was lazy before.  Here's the return loss after the cable was cal'ed out

Al

[N3DRB The Derb]

sweet!    I have the much older brotha to yours, decked out in battleship gray.

Terminal-Lines    r sure nice to have around, even if you dont use em much.

That's @ 2.5ghz? I didn't think that was rated that high.

[w1vtp]

sweet!    I have the much older brotha to yours, decked out in battleship gray.

Terminal-Lines    r sure nice to have around, even if you dont use em much.

That's @ 2.5ghz? I didn't think that was rated that high.

Yep -- it's spec'd to 2.5 GHz at reduced performance.  0 - 1 GHz = 1.1:1 (-26.4 dB) 1 - 2.5 GHz - 1.25:1 (-19 dB).  The NA display would be a lot cleaner if I had cal'ed out the cable.  I was just looking for troubles of which there aint.

Al

[WBear2GCR]

Al,

Does that one have a connector on the aft end?

I got one that is nominally an "attenuator" because it has a connector on the aft... but I found it was 50 ohms input looking in, so if FB as a dummy load...

            _-_-bear

[W2XR]

Al,

Does that one have a connector on the aft end?

I got one that is nominally an "attenuator" because it has a connector on the aft... but I found it was 50 ohms input looking in, so if FB as a dummy load...

            _-_-bear

Bear,

Me too. I have a Bird 2000 watt, 30 dB, 50 ohm Tenuline coaxial attenuator that works FB as a 2KW dummy load. Although I also have a Bird 1000 watt Termaline dummy load with the built-in RF wattmeter, I find myself using the 2 KW attenuator as a dummy load almost exclusively at this point, as it can readily handle the output power my rig is capable of. Plus, I can easily couple my 'scope to the attenuator output with the simple addition of a 30 dB 1 watt coaxial attenuator.

I was real lucky; I picked it up for $10 from a local surplus joint last year.

At one time I had a Bird 4000 watt water-cooled dummy load; I used to connect it to the faucet in the basement and that thing would run at virtually room temperature with 2400 watts PEP of AM dumped into it for extended testing sessions. I think it was good for 600 watts steady-state without coolant flow.  If I recall correctly, the 4000 watt rating was at a coolant flow rate of 1 GPM.

73,

Bruce

[w1vtp]

Al,

Does that one have a connector on the aft end?

I got one that is nominally an "attenuator" because it has a connector on the aft... but I found it was 50 ohms input looking in, so if FB as a dummy load...

            _-_-bear

Nope.  I have one of those attenuators at work.  I used to calibrate a broadband KW with it  - Sweeet -- 100 KC to 230 MC.  A monsta using a gazillion of 4CX250s.  And yes, with a return trip of 60 dB, that would make a great load too.

Al

[w1vtp]

Bruce

If you had an accurate flow rate meter, an inline thermometer in and out, you have the makings of a calorimeter -- yet another way of measuring power

Al

[W2XR]

Bruce

If you had an accurate flow rate meter, an inline thermometer in and out, you have the makings of a calorimeter -- yet another way of measuring power

Al

Hi Al,

Nice dummy load you picked up at Deerfield, OM!

Yup, I had thought about that back then: delta T and flow rate, and the subsequent conversion of heat to watts.

I swapped that thing to a local VHF-bound ham a number of years ago; he has never used it with liquid cooling, as he never had the need to dissipate the kind of power the load was capable of. As such, he has always used natural convective cooling, and it easily can  handle the 600 watt power rating without any coolant flow.

73,

Bruce

[W1UJR]

Hi Al,

Did you buy that Bird dummy load from Gary WZ1M at the NEARFest?


-Bruce

[w1vtp]

Hi Al,

Did you buy that Bird dummy load from Gary WZ1M at the NEARFest?


-Bruce

No.  And I wish I had caught Gary.  I have a need for a 20 - 30 HY mod reactor.  The guy was located diagonally across from Dale KI1W's hook up.

Al

[W1UJR]

Ah, very good.

Gary had a Bird like that, and I was there when someone picked it up.

Sorry I missed you Al, was there Saturday only.

-Bruce

[WZ1M]

Yep, and I sold it for 20 bucks
Gary...WZ1M

[W1UJR]

Well someone got a bargain Gary.

Thanks for the super job on the National doghouse supply, hope to get that fired up this week.
Short days and long nights are here, prime radio ex.