[TenTec] Using a 253 Tuner in a Contest

[Ken Brown]

Hi Eric,

I also have a 253 Autotuner. I have not yet interfaced it to my Omni VI. 
I don't have the cable to do so, and haven't taken the time yet to make 
one. I am not sure exactly how I will interface it to the radio when I 
do make the time to do it. The way I would like it to work and what it 
sounds like you are wanting it to do, is not what is going to happen 
when you do it the "normal" way shown in the manual. The 253 has only 
seven band select inputs. The band select outputs from the Omni VI are 
something like 160, 80, 40, 30, 20, 15 and 10 meters (maybe 80 & 75 and 
not 30, I don't know yet) so you will not get multiple memorized tunings 
for each band on a single antenna.

Some people have uncoupled the RF section of the antenna switch from the 
rest of it and then used that switch to give them four memories for each 
of the seven bands. This is a little closer to what I would like, 
although I still will want more than one antenna. An external antenna 
switch would be one way to go.

Another possibility would be to use a remote selector switch as 
described in the manual, without any direct control from the radio. I 
might use the seven band selections something like this: 160L, 160M, 
160H, 80, 75, 40CW, 40SSB. And then still have the ability to have four 
antennas connected to the 253 using it's switch, with memorized tunings 
for each antenna. Of course you can see that this doesn't cover every band.

Yet another possibility would be to have 28 memories selectable with a 
separate switch or switches, not directly controlled by the radio or the 
antenna switch at all.

If you don't use the memories of the 253, you will have to endure it's 
autotuning search routine everytime you change bands or antennas. I 
don't find this option acceptable so I am presently using my 238 and a 
look up table to manually tune it. The tuning is surprisingly 
repeatable, with only minor adjustments away from my table values 
depending on rain and wind on the antenna. I can get there sooner (and 
quieter) with the 238 than with the 253. So the 253 sits waiting for me 
to decide how I want to use it and then built the necessary cables and 
switch box, or whatever.

I like the way my SGC SG-235 tuner works. It apparently has a frequency 
counter, or other frequency measuring circuit buit into it, which then 
addresses memories for tuning settings. I do not know how many memories 
it has, or what the frequency resolution is. I am pretty sure it has 
much greater than the 28 memories that the 253 has. It is only rated for 
500 watts though.

I really wish somebody would market an auto tuner that works as good as 
the SG-235, can handle a full 2000 watts (I mean real watts, not MFJ or 
Vectronics watts) is an L network and is affordable. I think I would 
prefer a servo controlled roller inductor, like in the Ten-Tec 238 and 
also a servo controlled air or vacuum variable instead of a bunch of 
fixed value capacitors and relays like the SGC, LDG and many tuners use. 
The matching autotuner for the Kenwood TS-50 (and the internal auto 
tuner in many Kenwood rigs) uses servo controlled air variables, but is 
a T network with only 1 inductance value for each band. They work pretty 
good, but only at 100 watts and not very wide impedance range.

I would also like to hear what methods others have used to get the most 
out of their Ten-Tec 253 Autotuner, and I am also interested in 
information about other 2kW rated autotuners.

> I've recently picked up a 253 Autotuner that I will be adding to my 
> station, which consists of an Omni-6 Plus and Herc II (and 301 remote 
> encoder).
>
> I'm curious to know how to integrate the 253 into my station for 
> contesting purposes, where I presently use a tuner to help me 'walk' 
> up and down specific bands (160, 80 and, to a lesser degree, 40) where 
> the antennas are quite narrow banded.  I note that the tuner demands 
> <150 watts to tune,  which makes me wonder if I have to turn the amp 
> off each time I move up or down in frequency in a given band?
>
> I'd appreciate comments from those of you who have experience using 
> this otherwise impressive box in a contesting environment.
>
> Thanks in advance,
>
> Eric W3DQ
> Washington, DC
> _______________________________________________
> TenTec mailing list
> TenTec at contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec
>