OTT-847 interface for LDG antenna tuners
W4RT Electronics came up with a new interface
to connect to LDG antenna tuners. With this interface it is possible to use
the CAT software "FT847-SuperControl" to automatically engage a tuning
process with LDG antenna tuners when the transceivers frequency has been changed
(No-Touch Tune). Click >> here << to see
a picture of the OTT-847 interface.
As we all know, tuning the FT-847 with other than the Yaesu FC-20 Tuner is simply
annoying at best. In addition, the FC-20 has a poor tuning range (3:1 SWR) although
it is nicely integrated into the operation of the FT-847. Oh, did I mention
that one can't use CAT when using the FC-20? This message is to announce that
W4RT Electronics and SuperControl Amateur Radio Software have worked together
to solve the problems of no CAT and to allow autotuning with tuners having a
broad tuning range (10:1 SWR)! During the past two years, W4RT Electronics has
developed One-Touch Tune Modules for the FT-100/D, FT-817, FT-857, and FT-897
radios, which allow them to be easily used with third-party tuners, particularly
LDG Electronics autotuners. W4RT and LDG are affiliated companies. Unlike the
other radios, the FT-847 has been a particularly challenging radio for which
to develop a One-Touch Tune module. The following several paragraphs will describe
the new system.
The first new feature of FT847-SuperControl is the support for the new W4RT Electronics One-Touch Tune (OTT-847) interface. With this interface it is possible to automatically control antenna autotuners from LDG Electronics. At present, the LDG autotuners AT-11MP, RT-11, and AT-1000 are supported, as will be future models. The OTT-847 connects to either the 9-pin DIN connector on the FT-847 or your computer port used to control the FT-847 by CAT. The OTT-847 has an internal null modem, a cable to connect to the FT-847, and a cable to connect to the LDG tuner. FT847-SuperControl now offers a "One-Touch Tune" function where you can start a tuning process on a connected LDG autotuner simply by pushing a button on the computer monitor screen. The software will command the OTT-847 interface and will change the FT-847 mode to generate a stable carrier needed for the tuning process. After the successful tuning, the original operating mode will be restored and you can start operating on the new frequency (typically 1-3 seconds).
Of course, the FT847-SuperControl is able to detect when the Tune button on the LDG autotuner is depressed. In this case, the software will also command the OTT-847 and the FT-847 to produce a proper signal for the tuning process. Now if that isn't great enough, then give the "No-Touch Tune" function, which is also available in the software, a try! In this mode, FT847-SuperControl automatically detects a frequency change of the transceiver. If the frequency change exceeds a user predefined step value, the software will tell the OTT-847 interface and the LDG tuner to start the tuning process automatically. In other words, you don't have to push a button on the screen or the tuner to have the LDG tuner perform a match at a desired frequency. This will be done automatically. In-band QSY retuning takes typically about a second while band changes may take several seconds.
Supported LDG tuners are:
AT-11MP, RT-11 and AT-1000 (as will be future models)
AT-11 Auto tuner
Considering the limitations of using the CAT feature and the FC-20 with the
radio, some owners have opted to purchase the AT-11 auto tuner from LDG
Electronics. This is available in either a kit or assembled format and does
not suffer from the CAT/FC-20 limitations.
Update 08Jun00: The AT-11 tuner has undergone some major revisions and is now the AT-11MP model. It has some new features (e.g., meters, remote unit) that seem to be very nice.
Update 20Mar00: There is a wide variety of jumper settings that you can make that affect RX, TX, or both at once. Colin's page has a nice table that shows all the combinations of jumper settings and the RX and TX ranges for each setting of the blobs. Take a look. This information should be of interest to European hams, where the RX range is limited depending on the country in which the radio is marketed.
Loss of ARS after TX Modification
If you do the modification to open up the transmit range, you will find that the Automatic
Repeater Shift (ARS) feature no longer works. This is apparently due to the fact that the ARS is country-specific.
You might ask why it wouldn't work on the new country's ARS pattern that you set the rig to. Don't know why. Perhaps
the modifications that people have found change something besides just the country setting.
[Return to Main Menu]
Separate Receive and Transmit Lines on 2m & 70cm
Peter OZ1PIF has made a modification that will separate the RX and TX lines for 2m and 70cm. By adding two additional antenna jacks on the rear and by making a small mod inside, Peter has enabled a separate RX port for each of the two bands. This will facilitate adding pre-amps and interfacing amplifiers. You can see some detailed pictures of his modification by checking out his web site, http://www.frenning.dk/oz1pif.htm.
The solution developed can be applied to any low-voltage DC-driven fan, but
here it's been implemented specifically for the FT-847. (Thanks to Thomas, OZ2CPU
for original circuit idea)
(click for circuitry picture)
None of the component values are critical, and any N-channel MOSFET with a reasonably low on-resistance can be used. I selected the IRF510 because I had a supply already in my component drawer, and because it's cheap (~ 0.3$)
(click for fan controller picture)
The circuit has been mounted on a hand milled PCB (size 10x20mm). In the picture the NTC resistor has just been soldered on with long leads for testing purposes. Where available SMD components have been used.
(click for fan controller in place picture)
Here the Fan controller has been mounted in the VHF/UHF PA compartment of the FT-847, note that the 144MHz cable to the Rx side has been removed for clarity. The MOSFET has been wrapped with a small piece of electrians tape to make sure that there is no contact between the Drain flange and the PA board. The controller PCB itself has been fastened to the chassis with a small piece of adhesive foam. The lead from the fan to the connector has been cut, the red lead to the fan soldered to the + 12V pad and the black the the Drain pad on the controller. The rest of the leads, leaving the connector has been taken to the + and - 12V pads on the controller using two approx. 5 cm long leads. The NTC resistor has been glued to the chassis for positive thermal contact.
Final adjusment for approx. 3.2V on the Gate finishes the job.
Now a temperature increase of 5-6 degrees centigrade will cause the fan to start, and it'll continue to run at required speed until everything has cooled down sufficiently. Note that the supply voltage for the fan drops about 1.5V when transmitting, causing the fan to increase speed in Rx mode (until subsiding with temperature decrease)
Update 11/26/99: Chuck AA6G reported his results on adjusting the FM discriminator reading. This report is interesting because he used the menu to customize the discriminator to show deviation over the greater range than the stock settings. I'll reproduce his results verbatim.
"I was reading the FAQ and decided to adjust my discrinator setting since it was a little off too. I used
an HP-8640B as the signal generator. It seemed as though the DISC-L and DISC-H menu items should be the low and
high adjustments and indeed they appear to work that way. I found the total range of my meter to be less than 2KHz
and I wanted a little more range.
I was able to get +/-5KHz by setting DISC-L to 21 and DISC-H to 38. My meter now moves off center one segment at
about +/-500Hz. The tradeoff is less sensitivity to a small frequency change but a greater range. I suspect you
[could] get +/-10KHz if you wanted it.
"You can perform this adjustment with an on-the-air signal if you have one you trust to be accurate.
Simply tune above and below the signal the amount you want and adjust the menu item so the meter just
reaches the limits."
Adjusting the Transmit Gain - PLEASE READ ENTIRE DISCUSSION BEFORE CHANGING ANYTHING!
I recently used the alignment menu to adjust my TX-GAIN to see what would happen. First, though, I wrote down what
the setting was before doing anything. There are actually six different TX-GAIN settings: 70cm, 2m, 6m, 10m, 20m,
and 160m. You will need to tune your rig to the band you want to adjust, then go into the alignment menu by holding
down the three buttons on your stock mike while turning the rig on. Use the Sub-Tune knob to turn to TX-GAIN. Write
down the setting, and remember that it's only for the band you're on. Now, you can use the MEM/VFO CH
knob to change the TX-GAIN value. Mine was at 8F to begin with, and I was working on the 2m band.
As I reduced the values, nothing happened until I got down to about 48. Between 48 and about 41, the output power
began to drop off quite a bit. By 40, I could not measure any output on my watt meter. I then returned the setting
to 8F and things were back to normal. I did not try increasing the value beyond 8F. Even after changing
this value, you can use the RF PWR knob to reduce the power below the maximum value.
You can actually check things as you go. After turning the MEM/VFO CH knob, you can still change modes and key
the rig with a CW carrier. This way, you can check the resulting output instantly without having to return to normal
operations. Once you have a setting you want, press the MENU button to return to normal operations. You can return
to the alignment menu as often as you want to change things some more.
This ability would seem to be particularly helpful for hams running amps that have, say, a 10 watt input. If you're
always using the amp, you could adjust the TX-GAIN to limit output and protect your amplifier. There are some tradeoffs
on doing these adjustments. Please see the discussion on Limiting Maximum Output Power for
an explanation from Yaesu.
Note: Two of us have stumbled onto something you should know about. We think that, if you are fooling around with
TX-GAIN and you change bands with the band switches while you are in the alignment menu, it may transfer
the TX-GAIN setting to the register for the band you just switched to. All the more reason to write down all the
values before you begin fooling around with the Alignment Menu.
Update 20Aug00: Another way to control power output of your FT-847 is by using the ALC control circuit. Click here to read about how to use ALC to control power output.
Typical Alignment Menu Settings
I include here my alignment menu settings in case it might help someone with a problem. I don't think I've changed any of these from what the rig came with (but I might have!). I'm sure your settings will be somewhat different from these, so this information should be used for comparisons only. There are 25 different settings and some of those have multiple values, depending on what band you're on. I know that at least one has two values that are accessed by using the A-B swap button. Also, I don't know what many of these do!
FM-S1 58
FM-FULL 89
RX-GAIN 75(160-30), 93(20-15), A2(12-10), 6B(6m), 43(2m), 47(.7m)
SQL-TH-L 5A
SQL-TI-L 00
DISC-L 24
DISC-H 30
SSB-S1 DD
SSB-S9 5E
SSB-FULL 26
SFT-CTR 7F
RXC-PNT 00
TXC-USB FE
TXC-LSB FA
PWR-100W 91
PWR-50W 62
PWR-20W 3E
PWR-10W 2B
ALC-1 06
ALC-9 2F
TX-GAIN AF(160-30), A8(20-10), 8F(6-2), 64(.7m)
SWR 1.5 12
SWR 3.0 3E
ALL-CLR 00
DSP-PASS 00