It couldn't get much cheaper 

David,

The FT-847 does NOT user the Tuner DIN connection for amplifier control.  It uses the Standby "STBY" DIN connection for amplifier control.  As I recall, there are 5 pins used, one ground and the other four for the respective bands that the radio operates on (HF, 6m,2m, 70cm).  Whichever band is in operation shorts the "in use" pin to ground to trigger the amplifier.  I have the documentation with pinouts and load ratings at home.  Email me (my call @arrl.net) with a way to send the docs to you and I'll do so this evening.  Please don't attempt to use the tuner jack to control an amplifier or you will release the magic smoke. 

Stephen
N5VTU

I guess no one has changed a mode switch in a TR7??

Look at JTE's nethod. He uses Rat shack relays no prb.  I talk to him all the time and they work quite well.

http://www.eham.net/articles/26865

This is on my lisy to try this weekend.

73  Dave  KD8GEH

There's your problem right there.


Nobody's disputing that you need a tuner to operate in other band segments with a small-bandwidth antenna.  They're disputing that you can't fix part of the problem.  Why spend hundreds if not thousands on a new high-power autotuner when you could take a couple of hours, a little bit of work and raise the antenna?  You'll at least find out if the interaction with the house you've admitted might be taking place is actually the cause.  Plus "higher is better", right?

If your antenna's bandwidth is so small that it presents a 6:1 SWR at the low end of the band, you're going to have loss in the feedline.  Depending on what type of coax you're using and the power you eventually run, you could waste a lot of power in heating the coax even with a high-quality tuner in the shack.

Someone mentioned running the autotuner closer to the feedpoint, and I think that's an excellent idea.  You could easily mount a weatherproof autotuner at/near the top of the tower, for instance, and have a very short coax run to the beam.

First thing I'd do is fix the problem with the impedance changing on the same frequency based on direction.  That's so easy, it's a no-brainer.  Of course just trimming the match with the autotuner is easier, but if there's enough junk in the antenna's near field to send the SWR wonky, it must be playing havoc with the pattern.  That's no help.  If all you have to do is raise it a bit, just raise the damn thing. 

Solve the problems you know you have now before you contemplate other problems you might face when you add an amplifier.

Cheers,

Bob WP2XX

Bad math.

Thanks Stephen
I have the operating manual that explain the Plug Pinout for the Tuner DIN connector which is what all keying cables for sale out there are wired for the FT-847 amp keying. I know at the other end of the RCA plug that goes to the Amp is GRD and TX.

TUNER PINOUT
1-pin =13v, 2-pin= tx GRD, 3-pin=GRD, 4-pin=Data, 5-pin=data/out, 6-pin=tuner sense, 7-pin=reset and 8-pin=TX INH

Does this mean that if I were to make my own cable I would wire it to the #2 pin= TX/GRD and #8 pin to TX/int ?

Depends on what your goals are. I sold some stuff last year, a few single band mobiles, an Elecraft K2, a few old HTs. I put a high price on the K2 (basically what I paid for it), not sure if I wanted to get rid of it, but everything else was priced to get it to someone who could use it. The first guy came past and bought the K2 without a second thought. The rest of the stuff sold with no negotiation. I was very surprised. I also labeled everything that didn't work as a parts box and made sure the buyers understood that.

I've been on the other side too. I'll haggle with sellers too, even if there's a low/fair price on an item. Gotta try, I figure. But then I'll haggle in retail stores too.

ok, thanks. I actually think I have some of that in a box in the basement.

The ARRL focus is on the Division conventions (http://www.arrl.org/hamfests/rocky-mountain-division-convention-hamcon-colorado-2013), not a large national event. That leaves a hole that ends up getting filled by Dayton. If it wanted to, the ARRL could hold a national convention, but that takes resources away from the divisions and other efforts. And the whole point of conventions, at least in my industry, is to get a bunch of vendors to pay big bucks to set up on the show floor and set up shop. Trying to find enough vendors that would be willing to set up (and staff) a booth for a few days isn't easy, and there are enough retail locations that we can check out equipment we're interested in any time anyway.

The other side of a convention is going to seminars that may or may not be useful. Since we're a learn-by-doing group, sitting through a talk about a subject might not be as useful as just trying it out. Although it is fun listening to Bob Brunninga complain about the APRS network.