Automatic antenna tuners
 

I'm getting back into radio after a 20 year absence. Back then, I had
a QRP rig and a novice license; didn't worry too much about my antenna
unless the SWR meter went past 2.5. What I did not have was an
antenna tuner.

Now that I'm older and wiser, I realize an antenna tuner is probably a
necessary thing to have. I'm putting up an 18' Hy-gain 5 band
vertical antenna, leading to a Yaesu FT840 @ 100 watts. The matching
ATT is not available, unless I'm willing to bid on E-bay for a hundred
more than it cost new. (Believe me, I've tried this.) But I don't
know what I should use. I know some tuners are designed for a
specific rig.

Does anyone know what I should get? I'd really just like to turn on
the radio, move to a frequency, turn on the ATT, and tap away. Help!

Automatic antenna tuners
 

ehoops wrote in news:2bb452d8-e127-42a6-bbb0-
:

....
Does anyone know what I should get? I'd really just like to turn on
the radio, move to a frequency, turn on the ATT, and tap away. Help!


Firstly, is an ATU really necessary with your antenna. One of the
selling points of these kind of antennas is that they are a fair match
to 50 ohm line... though an ATU might overcome to some extent the narrow
bandwidth on the lowest bands.

Next, there are a range of generic automatic ATUs, they fall broadly
into those intended to go into a coaxial line and those intended to feed
unbalanced loads like end fed wires, monopoles etc. The each have
different matching ranges and applications.

Some of these generic auto ATUs can be interfaced to proprietary ATU
interfaces on transceivers. Some transceiver support for ATUs is quite
poor and might be construed as a marketing ploy, eg most Icom
transceivers seem to abort a tune process after about 18s, so they do
not integrate well with an ATU that might take 30s to find a match.

This lack of open interface, and flexible support is a problem. I
attempted to design a protocol converter to properly integrate an SGC237
with an Icom radio, but I abandoned it because the SGC cannot be
guaranteed to complete within 18s, and if it has to restart, it restarts
from scratch and the same problem occurs. On the other hand, I was able
to make a reliable protocol converter for a 'screwdriver' type ATU, as
in the rare circumstance that the tune had not completed when the Icom
aborted, the coil contact was closer to the desired point and in tests,
always completed on the next attempt.

So, in my experience, Icoms work reliably with Icom ATUs, but have
issues with some non-proprietary ATUs. This is why I say that ATU
support is used as a marketing ploy.

Owen

Automatic antenna tuners
 

"ehoops" wrote in message
...
I'm getting back into radio after a 20 year absence. Back then, I had
a QRP rig and a novice license; didn't worry too much about my antenna
unless the SWR meter went past 2.5. What I did not have was an
antenna tuner.

Now that I'm older and wiser, I realize an antenna tuner is probably a
necessary thing to have. I'm putting up an 18' Hy-gain 5 band
vertical antenna, leading to a Yaesu FT840 @ 100 watts. The matching
ATT is not available, unless I'm willing to bid on E-bay for a hundred
more than it cost new. (Believe me, I've tried this.) But I don't
know what I should use. I know some tuners are designed for a
specific rig.

Does anyone know what I should get? I'd really just like to turn on
the radio, move to a frequency, turn on the ATT, and tap away. Help!

I have an internal autotuner but one ham buddy uses an LDG auto tuner for
100 watts and he's happy with it. (He uses a high-power manual tuner if
he's using his amp. ) http://www.ldgelectronics.com/

Some models, LDG or other, may be more suited to the FT-810; some radios
have a TUNE button that talks to the tuner via a custom cable, while
putting out Tune Power, about 10 watts. Otherwise, there should be no great
difficulty in you dialling up a tune power output and invoking the TUNE
finction on the tuner.

Good luck, OM

Automatic antenna tuners
 

On Sun, 31 Jul 2011 13:30:17 -0700, ehoops rearranged some electrons to
say:

I'm getting back into radio after a 20 year absence. Back then, I had a
QRP rig and a novice license; didn't worry too much about my antenna
unless the SWR meter went past 2.5. What I did not have was an antenna
tuner.

Now that I'm older and wiser, I realize an antenna tuner is probably a
necessary thing to have. I'm putting up an 18' Hy-gain 5 band vertical
antenna, leading to a Yaesu FT840 @ 100 watts. The matching ATT is not
available, unless I'm willing to bid on E-bay for a hundred more than it
cost new. (Believe me, I've tried this.) But I don't know what I
should use. I know some tuners are designed for a specific rig.

Does anyone know what I should get? I'd really just like to turn on the
radio, move to a frequency, turn on the ATT, and tap away. Help!

I agree with Sal, LDG makes a good product. I have a Z11Pro2. It
doesn't require any interface with the radio, it measures the incoming RF
and antenna side SWR to know when to tune. It also latches the settings,
so it stays set up even if I take power off of it (which I do when I'm
not trying to tune it).