TH-77A miscellany ================= (Part 1) From the factory, it can receive 138-174MHz and seems to do it quite well with the supplied rubber duck antenna. It also can receive 438-450MHz and, likewise, does this quite well too! One very interesting feature of the TH77A is that it can do *DUAL* UHF receive! To do this it uses the VHF receive section and you have less sensitivity, but I really haven't noticed much signal degradation at all. Kenwood has made this radio compatible with the new ICOM S-Series radios from what I can tell. It has DTSS (Dual Tone Squelch System) which means that your radio will not break squelch until it hears a particular sequence of three DTMF tones (ICOM has this also and they call it Coded Squelch which also use three tones). The TH77A also has a paging function that works *exactly* like the ICOM paging. You program the radio with a personal 3 digit DTMF code and someone pages you by transmitting YOUR 3 digit code, followed by a * character and then their own 3 digit code. The ICOM will start to ring to let you know that you have been paged and display the 3 digit code of the person that has paged you. The TH77A will beep once and open squelch as long as the person that paged you does not drop carrier (I prefer the ICOM method for this part, but there is a trick around that I will mention in a bit). One thing the TH77A does at this point is bring up a timer so you know how long its been since you've been paged. Maximum time is 99 hours and 99 minutes. Let's see if your battery can hold out that long! The trick so the TH77A will ring, rather than just beep and open squelch is to put the radio in the pager mode AND also put it in Tone Alert. When you get paged... the radio will "beep beep (pause) beep beep" five times and start up the timer. Kenwood has provided two different types of BEEPS for you. The second type is to ring like an electronic telephone. This one *REALLY* sounds nice! For those of you that like autodial memories, there are 10 memories that can store 15 characters each. There are 40 regular frequency memories in this radio and you can make them all UHF if you like (no restriction). NOW! On to the *EXTRA* capabilities (there are other BASIC functions that I didn't mention, those were just the highlights). After making a few modifications to this radio, you can get it to do the regular stuff that the IC24AT will do, such as AM aircraft, expanded UHF (400-512 depending on PLL lock) and 800-950 (again, depending on PLL lock) in addition to cross band repeat. HOW DO YOU DO THIS? Easy (if you've got a steady hand for removing a chip resistor). Open it up. There are 3 screws visible on the outside and 4 more underneath the battery pack. Unlike most radios, this one doesn't have a spring for the battery release switch. It gets spring action from the metal plate that you will remove when you take out the four screws. The area you will be working in is on the control board which is fixed to the front section of the radio. In particular, look for the yellow electrolytic capacitor (its yellow in mine) that is at the dead center of the board (there are two IC's, one above this and 1 below this). You will have to remove the electrolytic capacitor (C124) and set it aside for a few minutes. You will be putting it back afterward. The reason for removing this is so that you can remove a chip resistor that is underneath it. To avoid tearing the flex board foil traces, do not bend the leads of the capacitor. There is a green wire that is connected to one side of this capacitor. If you disconnect one side of this green wire, you will get RX from 400-512 (PLL lock depends on the radio, but you can DIAL from 400 to 512). Orient the radio so that the volume controls and BNC are at 12 O'Clock on your table (farthest from you) and the bottom (where the battery connects) is at 6 O'Clock (nearest you). In the area where you removed the capacitor, you will see a blank space where there could have been a chip resistor followed by two chip resistors side-by-side and in the next row below that, you will see 3 more that are side-by-side. There is one to the left of these two rows that is kind of off center. Now, there are three ways to configure this radio at this point: Cont'd in part 2 (Downloaded from GB7SYP)