TH-77A miscellany ================= (Part 3) One more feature worth mentioning for humour value: If you hold down M and PTT and power up, the HT enters "game mode". You get "0000" on the left of the screen. Press "0" and digits start changing rapidly in hex (consequently all appearing as "8"). By pressing 1,2,3 or F you stop the appropriate column. If they all come up the same, er, well I guess you win... maybe something good happens then. Maybe it enables transmit on, cellphone, air, and 30cm :-). At 1 chance in 65536 I'm not about to try to find out, though... Despite what I said in my previous msg about not wanting to try it, I just did. Much to my amazement, after only one or two minutes, I won! By timing the keypresses very carefully, one can improve the chances from 1 in 4096 significantly, it seems [ignore my "1 in 65536" in my previous mail, obviously I wasn't thinking straight.. obviously there are 16 winning combinations out of 65536] And yes, something Interesting does happen when you get all four numbers the same (at least when you get "2222" like I got). More specifically, the display starts doing something humorous. Pontus Hedman I have serial number 20603908 and 20603539. UHF receiver beeps in the following ranges: 400-417, 460-468, 860-880. The 400-417 seems to match mine exactly! The other two are different. Mine beeps between 460-464 and 864-874. VHF receiver in UHF mode beeps in the 489-512 range. It does appear to be more sensitive below 489 than the 'real' UHF receiver. VHF receiver in 118-136 mode seems most sensitive around 121MHz. I could receive aircraft around 133.65, but had difficulty in setting the squelch to still be able to hear weak signals there. Well, I haven't played much with AM to be sure where its more sensitive. It does copy 124.900 quite well (LAX approach). I only hear the planes though and I haven't been able to hear any ATIS stuff. I did have to separate the cap from the glue holding it down. In fact, I separated the glue from the plastic film over the IC, and later applied a spot of epoxy to reattach the glue to the plastic. I had to use a lot of force to cut that glue away. It was VERY scary doing that! I didn't think of gluing it back though. I've been using the PB-7 on it a lot. That 1100mA sucker lasts forever! I don't mind the size of the radio with it on either. I used to have the Yaesu FT-727 and upgraded to this one. I really couldn't stand the large antenna on it. This one is very nice and doesn't seem to have the problems that the IC-24AT does (people have been saying its more of a dummy load than an antenna! Gerald J. Walsh Many of the TH-77a's with 206* serial numbers have problems with memory loss when they are operating and the pack runs down. This is cured by a resistor change. AES replaced it in my TH77 without charge. I don't know which resistor needs to be changed, however. Also, some of the newer TH77a's seem to have a tone mixing with the audio. PL disable has no effect; speculation points to a dc-dc converter in the LCD display circuitry. Due to the weak audio I generally run the volume near max. And I find that my ears are hurting from the high-pitched noise when the HT squelch closes. This is most irritating! I recently did some sensitivity measurements of the TH77A. Here are the results again: SENSITVITY MEASUREMENTS TH-77A USING AN IFR MOD 1000S SERVICE MONITOR 1000 HZ TONE REFERENCE IS 2 LCD SEGMENTS LIT FREQ. SIGNAL MHZ MICROVOLTS 118 1.6 AM 123 0.5 128 0.5 133 0.7 136 0.8 136 0.3 FM 141 0.3 146 0.4 151 0.4 156 0.4 161 0.5 166 1.0 171 2.0 174 2.5 FREQ. SIGNAL SIGNAL MHZ uV. uV. VHF VFO UHF VFO 400 8.0 NO RX 410 3.0 20.0 420 2.0 5.0 430 0.8 1.0 440 0.5 0.3 450 0.7 0.3 460 1.0 NO RX (birdie?) 470 1.7 3.5 480 3.0 20.0 490 5.0 40.0 500 7.0 50.0 512 NO RX 80.0 800 30.0 810 15.0 820 5.0 830 3.0 840 2.0 850 1.7 860 NO RX 870 3.5 880 4.5 890 5.0 900 6.0 910 8.0 920 11.0 930 15.0 940 15.0 950 15.0 James Dugal, N5KNX @ K5ARH (Information provided by G1YYH @ GB7TCP) (Downloaded from GB7SYP)