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If you are going to claim what I said is plain wrong you are going to need more than a rambling response to bolster your standpoint. https://m0ukd.com/calculators/quarter-wave-ground-plane-antenna-calculator/ "A quarter wave monopole mounted against a perfect ground will have an impedance of...

The main reason you are getting more PEP with the amp on high running the 148 is because with the amp on low side, the 101E is only driving the 4 final tubes with 110-120 watts PEP. With the amp on high driving with the 148, the two driver tubes are hitting the 4 final tubes with 180-200 watts PEP.

Keep it below 300 dead key, 1000 PEP and don't drop it on it's side from more than 4 feet off the ground and it'll keep working great.

There my be DC coming from pin 8 of the IC riding with the audio signal (which might be normal if the output of the IC is floating). C8 is the blocking cap for the base. Try lifting C8 and see if the 4.99V on the base is coming from there. If so, replace C8.

The 2SA1286 has the same pinout and package size and very close ratings. It should work fine as a replacement. https://www.rfparts.com/rftransistors/transistor-2sa/2sa1286.html

I'm pretty sure @NZ8N IS one of the pros..

This is a very comprehensive list but there is one more function that hasn't been covered. The O F F switch. This switch supersedes all of the other functions. If there is massive static, carrier throwers or any other form of undesirable operation, the O F F switch is the answer. Luckily this...

This is probably what Old Barney is talking about: Siltronix Manuals

On This thread, I recommended that you don't put the antenna dead center on the roof or you may have problems tuning it. Try moving it a few inches from the front or back edge of the roof. SWR is always changing in a mobile even if you aren't close to obstacles because the conductivity of the...

If you have a large roof, don't put it dead center or it may not tune. Even on a PU roof you can center it right to left but front to back, place it closer to the front or back edge. A quarter wave antenna wants to see some sloping ground plane close to the feedpoint.

6 pin is a Jones connector.

By golly it does say 10ma. An open or damaged bias diode can make the bias control not want to adjust low enough but I have emcountered on some models of Galaxy/Ranger radios where the factory resistor values on the bias circuit are incorrect. Check and even change D93 first and if it still...

The 1 watt loss on the 148/2000 chassis is from the tank being optimized for the Mitsubishi parts. Adjusting the value of C146 and/or C143 would probably gain the watt back for those that want it..

If the bias diode D93 tests OK, change VR13 to a 2K or change R276 to a 220 ohm half watt to give the driver bias more range on the low end. Are you sure it calls for 10ma? On most radios the driver bias calls for 25-35ma.

First off the HG transistors from ICA are genuine. I've used the HG 2166 and 1969 successfully on two Cobra 2000's. Both times the bias dialed right in and they ran ice cold. The only difference was about a 1 watt reduction in peak power compared to the original. A few weeks ago a member here...

Make sure D54 and R195 are intact. They are close to the AM regulator.

Change R67 next to TR17 to a 15 ohm, 1/2 watt. (or 1/4 watt if a newer board) R67 determines the gain of the bootstrap of the mic amp circuit. Lower the value the higher the gain.

That trimmer in the picture is W2. It's for setting the high end of the RF power to 12 watts (per the service manual) when the knob on the front is all the way up (clockwise). W1 (like I mentioned earlier in the thread) is for setting the low end range (CCW) of the front power control. The...

The Antec 12 volt PC fans are some of the quietest all plastic fans I've seen. Antec 120mm