August 1, 1974

HA-201						Bulletin No:

Walkie Talkie					HA-201-1



			Amplifier Instability



Differences in cable characteristics between suppliers cause some

amplifiers to oscillate. 



The two T/R switch transformers [T1 and T2] should be cut to 17 1/2

inches long.  This dimension will satisfy all 343-15 cables.



Future manuals will instruct the customer to cut to this new length

instead of 20".

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			September 25, 1974

HA-201						Bulletin No:

Walkie Talkie					HA-201-2



		        Instability Of The Drake TR-22/HA-201

			         Combination



To correct instability problems that may occur with the TR-22/HA-201

combination, install the following change:



	Change: 



	Connect a 150 ohm resistor [PN 1-66] between the center pin and 

	ground lug at the RF INPUT connector.



	Install this change only in HA-201 Amplifiers used with the TR-22

	Transceivers and only in cases where instability occurs on

specific

	operating frequencies.

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			February 14, 1977

HA-201						Bulletin No:

Walkie Talkie					HA-201-3



		             PN 417-803 Identification

						

++++Information not yet available++++

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			May 21, 1981

HA-201						Bulletin No:

Walkie Talkie					HA-201-4

		          Manual Correction For Q1



++++Information not yet available++++

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Thats everything I hold up to 1989 that covers the HA-201.  Enjoy!

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