Palomar Instrument 150 Mobile Linear

W5HRO

Amateur Station
#1
Picked up this old Palomar Instrument model 150 mobile linear. It was designed to work from 26MHZ to 54MHz, but was used mostly as a CB linear. There's enough room to add more C and L to make it work down lower on the HF spectrum. This must have been one of the early prototypes because it only has the stand-by switch on the front and then the AM/SSB switch on the back. The later ones had that switch on the front along with a High/Low power switch as well.

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W5HRO

Amateur Station
#2
Here is the schematic, but I think it's for the later one with the extra switches on front. At least those additions were drawn in by someone on 3-21-74.

Palomar_150_Schematic.gif
 

W5HRO

Amateur Station
#3
Picked up a lot of NOS 6LF6 tubes. These are the short version which take up less room. This is the best option to replace the old GE 8950 tubes. Many people today want to use 6LB6's, but the filaments draw an extra half an amp per tube compared to 6LF6's. Placing two 6LF6 filaments in series will actually draw 200mA less current than the two original 12V 8950 filaments did in parallel. Plus 6LF6's have more power dissipation than 8950's and handle higher voltages.

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W5HRO

Amateur Station
#4
I picked up this amp because I wanted something to possibly use with another tube mobile setup. It has the old-style solid-state vibrator using two PNP transistors which was better than the old mechanical ones. I'd like to at least make the thing work all the way down to 17 and 20-meters so the 17uH and 20uH chokes need to be increased first. I just ordered some high current 250uH ones (Hammond 1537M) for another amp which is overkill for this one, but they will still work. These are exactly the type of high current RF chokes that should work best in these sweep-tube amps just due to the nature of them being high current and voltage pulse tubes. The diameters are a bit large and I may have to maneuver things around a bit so they fit, but in a home-brew amp where you can have more space they would probably be ideal. I'm tempted to build a big one up using like 6 or 8 tubes in parallel for the final and then add some other single 100W tube or higher as a driver with tuned inputs and outputs so it's done the correct way. Maybe a future project down the road.

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