https://thelukens.net/Manuals/Electronics/Realistic%20TRC-221%20Owner's%20Manual.pdf Kind of an obscure site to see this, but this means that I don´t have to .PDF scan mine. BTW, this is a nice portable indeed, and I´ve used mine as a portable, mobile, & base, for years. One misprint is under RX Sensitivity, 0.5 mv for 10 dB (S + N)/N? I´m sure that meant .5uV. Adjacent Channel Rejection is better than many base & mobile CB´s at, 70dB! One thing that would have made this portable better would have been a NB = Noise Blanker. Still, I love my TRC-221. (UPDATE:) A bit of my history of mine, Bought mine in October 1990 for like $140.00, then bought the accessories, EXT Mic, wallwart charger, 12VDC Cig power cord, that 5¨ Realistic two-way speaker, custom vinyl case, a bunch of NiCad batteries, and a RCA male to SO-239 adapter to use with EXT antennas. All toll, +$200.00. A couple months in, the rig developed a warbler sound in the TX audio. Being under warranty, the Radio Shack dude that sold it to me wanted me to bring it back for an exchange for another TRC-221. Apparently, this HT CB was still being tested by Tandy Corp., so they really wanted my problem-ed unit. (I was cool with that.) So, I have the exchanged unit still, and no problems, except for a break in the LCD display that looks like an ink blotch. (UH!!!) Still, I can see the Channel numbers, the S/RF meter segments, RX/TX indications, and the Low BATT, all displayed, as well as the M-O-M PB wheat light for back lighting the display. Hopefully, I took notes, since it´s been a while, but there are ADJ´s for High Power, Low Power, PLL FREQ, and even a POT for RX AGC setting. (Wow...) No AM AMC ADJ on TX, so that´s a fixed value there. If I find my notes, I´ll post those here, as there seems to be little, to no INFO, out there on the TRC-221. All sorts of stuff on the TRC-216 CB HT. (Go figure.)