Posted: 3/27/2014 3:17:38 PM EDT
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What is the communication protocol between Icom 7200 and the AH4 antenna coupler ?
4 wire cable, red is battery positive, black is chassis ground. 5 volts on one wire, presumably from AH4 . Rig will not tune. Sent first AH4 back, second one is ( not ) doing the same thing. |
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You have this already?
http://www.icom.co.jp/world/support/download/manual/pdf/AH-4_Eng_2.pdf |
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Quoted:
You have this already? http://www.icom.co.jp/world/support/download/manual/pdf/AH-4_Eng_2.pdf And, at the risk of stating more obvious stuff, from the 7200 manual (and translated from Engrish): Tuning is required for each frequency. Be sure to re-tune the antenna before transmitting when you change the frequency—even slightly. The AH-4 will not operate on frequencies outside of ham bands. Operation: 1. Set the desired frequency in an HF band. 2. Push and hold TUNER for 1 sec--TUNE indicator blinks while tuning. 3. TUNE indicator remains ON after successful tuning is completed. 4. When the connected antenna cannot be tuned, the TUNE indicator goes out, and the AH-4 is bypassed and the antenna is connected to the antenna connector on the transceiver directly. To bypass the AH-4 manually, push TUNER--TUNE indicator goes out. See also the PTT tune function (p. 76) which, if turned on in the "set mode", will cause the AH-4 to be always tuned when [PTT] is pushed after the frequency is changed more than 1%. This function removes the “push and hold TUNER ” operation and activates first transmission on the new frequency. |
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Also, pinout is as follows: 1--Key (white) 2--Start (green) 3--Power (red) 4--Ground (black) Pin 1 is the pin at the pointy, triangular end of the connector. . My supplied AH4 cable is different green wire is at pointy end of connector. . . When connected, back of IC7200, BOTH white wire, pin 2 AND green wire, pin 1 are at 5 volts on rec., BOTH goes to ZERO when TUNE button pushed. no tuning occurs. |
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Quoted:
. My supplied AH4 cable is different green wire is at pointy end of connector. . . When connected, back of IC7200, BOTH white wire, pin 2 AND green wire, pin 1 are at 5 volts on rec., BOTH goes to ZERO when TUNE button pushed. no tuning occurs. Quoted:
Quoted:
Also, pinout is as follows: 1--Key (white) 2--Start (green) 3--Power (red) 4--Ground (black) Pin 1 is the pin at the pointy, triangular end of the connector. . My supplied AH4 cable is different green wire is at pointy end of connector. . . When connected, back of IC7200, BOTH white wire, pin 2 AND green wire, pin 1 are at 5 volts on rec., BOTH goes to ZERO when TUNE button pushed. no tuning occurs. You are WAY, WAY overcomplicating this. Ignore the colors, then. Use the wire you have. Use the above radio pinout (it hasn't changed on Icom radios since forever) and the AH4 pinout in Figure 2-1 of the AH4 manual. Wire Key-to-Key, Start-to-Start, Power-to-Power, Ground-to-Ground. Ohm it out and make certain (perform a continuity test). Make certain the AH4 is connected to some sort of antenna. If you haven't damaged either the radio or the AH4 from previous miswired attempts you should be immediately good to go. |
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Hrm. I'm baffled. Are you sure it's the right cable? Do all the pins run "straight through"? . yes, pins run straight thru. 13 volts DC confirmed inside AH4 tuner. will not tune. tried feeding RF power from TenTec Delta2 , with AH4 keyed, with LED and 2K resistor, per ICOM tech support.. still no tune. Hard to imagine two AH4 tuners, in a row, DEAD out of the box. Not sure what to think. . My OTHER 2 HF stations use auto-tuners, mobile has been running SGC 230 since 1994... House has a Stevens SEA 1630 running for a decade or so, no issues. |
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Obviously you are well familiar with this style of tuner given your experience with the SGC and SEA products. The simple answer is that either you are one very unlucky guy OR there is something wrong with the radio or installation that is eating up AH4's.
Did Icom ever tell you how/why the first AH4 was broken? That might provide a clue if it's radio/installation related. |
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With the AH-4 disconnected and disabled in the user menu, does the radio produce RF power into an antenna or dummy load? . The ( IC7200 ) naked, on the bench, with 14 volts solid DC input WILL output 100 watts RF ONLY into a 52 Ohm dummy load. I have tried various loops, dipoles, and Auto-Tuner fed ZEPs So far, radio will not feed power to any antenna, through any piece of Coax With the ICOM AH4, and 75 feet of 16 gauge in a tree, a brief 4 watt pulse is followed by transmitter shutdown. NO TUNING occurs. My copy of IC-7200 will NOT output sufficient power to ' activate ' tuning protocol on a known GOOD ( SEA 1630 ) auto tuner. Output is a maximum of 4 or 5 watts into SEA 1630 tuner, with 450 foot end fed wire, and a pretty decent ground system. . It would appear that the transmitter SWR or reflected power sensing circuitry is out of calibration. |
Sorry it was your radio 
The manual says you can tune with 5-15 watts of drive. Just bump the drive level up until the tuner activates or is there a problem for you in doing this. Your rig is not going to be damaged by increasing the drive level to more than 5 watts, so maybe a little more RF would make it happy. |
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Quoted:
. The ( IC7200 ) naked, on the bench, with 14 volts solid DC input WILL output 100 watts RF ONLY into a 52 Ohm dummy load. I have tried various loops, dipoles, and Auto-Tuner fed ZEPs So far, radio will not feed power to any antenna, through any piece of Coax With the ICOM AH4, and 75 feet of 16 gauge in a tree, a brief 4 watt pulse is followed by transmitter shutdown. NO TUNING occurs. My copy of IC-7200 will NOT output sufficient power to ' activate ' tuning protocol on a known GOOD ( SEA 1630 ) auto tuner. Output is a maximum of 4 or 5 watts into SEA 1630 tuner, with 450 foot end fed wire, and a pretty decent ground system. . It would appear that the transmitter SWR or reflected power sensing circuitry is out of calibration. Quoted:
Quoted:
With the AH-4 disconnected and disabled in the user menu, does the radio produce RF power into an antenna or dummy load? . The ( IC7200 ) naked, on the bench, with 14 volts solid DC input WILL output 100 watts RF ONLY into a 52 Ohm dummy load. I have tried various loops, dipoles, and Auto-Tuner fed ZEPs So far, radio will not feed power to any antenna, through any piece of Coax With the ICOM AH4, and 75 feet of 16 gauge in a tree, a brief 4 watt pulse is followed by transmitter shutdown. NO TUNING occurs. My copy of IC-7200 will NOT output sufficient power to ' activate ' tuning protocol on a known GOOD ( SEA 1630 ) auto tuner. Output is a maximum of 4 or 5 watts into SEA 1630 tuner, with 450 foot end fed wire, and a pretty decent ground system. . It would appear that the transmitter SWR or reflected power sensing circuitry is out of calibration. The AH-4 places a large resistive pad across the transmitter output during tuning (10 dB, IIRC) - which means that the SWR the transmitter sees is always pretty good, regardless of actual antenna SWR or tuner status. If your 7200's SWR shutdown circuit is sensitive enough to trip with that load, it certainly sounds like it's malfunctioning. |
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IC 7200 is operational.
AH4 tuner is working into approx 130 foot loop. Near 100% sure I was the sole malfunction, failed to properly wet the coax SHIELD with solder. center conductor good at both ends, no shorts, open shield. replaced PL259, ran a 50 watt, 12 volt bulb, at tuner end of coax line. clamp on ammeter showed 6 amps initial, and 5 amps steady from battery, with light bulb load. reconnected everything, tuner on outside wall of steel skinned building, tunes up all bands, FULL POWER. Talked to Fairbanks on 75 meters, first call. . . I feel both relieved, and like a dumbass. Thanks to all for tech support. |
At least it was the least expensive part of the system and easily repairable |
Here is a funny bit of background:
25 years ago, I worked as marine radio installer, technician. Probably soldered excess of 1000 PL259, a third of them outdoors, wind, rain, ladders, flying bridges, etc. ALWAYS check for shorts, ALWAYS. never once checked for current carrying capacity. always used Amphenol hardware, and usually made a quick file stroke to break through the nickle plate before installation. These chicken shit counterfeit PL259 imitations, packed with the ICOM dont fit right, unless you pull the braid BACK, over the jacket of the coax. Had never encountered that exact brand of chinese PL259. And admittedly, I hadnt soldered a PL259 in probably 12 years, or so. . . . . More irony: While fussing about, sad, dejected, and losing sleep, pissed about my supposedly NON-Functional IC-7200...... I ordered another one.. On the way from HRO in Oregon, IC-7200 and an SGC auto tuner. going to upgrade the Home station. , \ Now, which transistor do I use to ''' FIX''' the HM-36 Chinese Microphone ? |
