just ordered a heathkit sb-220 in very good condition...wish me luck
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ameritron 811-hd
- Thread starter 552fl
- Start date
The survival rate of that model is not so good. The aluminum chassis is too thin to withstand normal shipping stresses. When Heath sold the assembled version, it came in three cartons. One with the tubes, one with the amplifier chassis, and one with the high-voltage transformer.
It's always possible it will arrive unharmed, especially if it has a much thicker than normal layer of bubble wrap all around it.
Typically we see the transformer 'sunken' into the chassis deck. Frequently it will sag downward far enough to break off one or both of the circuit breakers underneath the HV transformer.
Just hope it wasn't packed up with the tubes still in the socket. That will guarantee a disaster.
This is the warning printed on the rear of the model that replaced the SB220/SB221, the HL2200.
Here's hoping it arrives intact.
73
It's always possible it will arrive unharmed, especially if it has a much thicker than normal layer of bubble wrap all around it.
Typically we see the transformer 'sunken' into the chassis deck. Frequently it will sag downward far enough to break off one or both of the circuit breakers underneath the HV transformer.
Just hope it wasn't packed up with the tubes still in the socket. That will guarantee a disaster.
This is the warning printed on the rear of the model that replaced the SB220/SB221, the HL2200.
Here's hoping it arrives intact.
73
Last edited:
made the trip with NO problem...just got threw running 220 in the shack
When you get it fired up, I suggest taking a second SWR meter and coax jumper to put between the radio and the SB220.
Key the radio, the foot switch and tune the SB220 for max modulated power.
Now, key them both, set the input-side SWR meter calibration and flip the switch to SWR.
If you see a high reading, now would be a good time to find this out. There is more than one possible reason for this. The input of an amplifier should fool the radio into thinking that it's connected to a 50-ohm antenna with a low SWR.
If the amplifier's input circuit is designed and adjusted right, it will be close to 50 ohms, and the input-side SWR reading will be below 2 to 1.
And if it's 4 to one or 5 to one, the radio may or may not be happy about this.
It's important to tune it up for max peak power first before doing this. The output adjustments will affect the input-side SWR. You want to know what this is under normal operating condition.
73
Key the radio, the foot switch and tune the SB220 for max modulated power.
Now, key them both, set the input-side SWR meter calibration and flip the switch to SWR.
If you see a high reading, now would be a good time to find this out. There is more than one possible reason for this. The input of an amplifier should fool the radio into thinking that it's connected to a 50-ohm antenna with a low SWR.
If the amplifier's input circuit is designed and adjusted right, it will be close to 50 ohms, and the input-side SWR reading will be below 2 to 1.
And if it's 4 to one or 5 to one, the radio may or may not be happy about this.
It's important to tune it up for max peak power first before doing this. The output adjustments will affect the input-side SWR. You want to know what this is under normal operating condition.
73