Hi folks,

I've moved to a country area in central MA and will be putting up a 40m
diople. Considering using a balun with my AT-250 tuner with mt TS-430.

If the tuner can tune in 20 and 10M, will damage be done to the 1:1 balun?

Thanks
NG1I

Frank,
Not unless the balun has a very low power/voltage
rating. Shouldn't make any difference if it's the
'usual' balun sold commercially, they normally can
handle the 100 watts (or so) you'd be putting out.
'Doc

Why are you building a new dipole with a balun in it, before you even know
if you need a balun? Try building the dipole with a "normal" center support
(Budwig, etc.) and put it on the air. If you see no problems, you're done.
Save the balun until you know it can be inserted to alleviate a problem,
rather than taking thechance on the balun BEING the problem...

73,
Mike KI6PR
El Rancho R.F., CA

"Frank MacKenzie-Lamb" wrote Hi folks,

I've moved to a country area in central MA and will be putting up a 40m
diople. Considering using a balun with my AT-250 tuner with mt TS-430.

If the tuner can tune in 20 and 10M, will damage be done to the 1:1 balun?

Thanks
NG1I

Dipoles at even multiples of the main frequency have a problem. The two
bands you mention should be the most difficult to tune with the tuner -
regardless of the balun question. These two bands put the feedpoint at/near
a high impedance feed point on the antenna. On 20 you have two half waves,
one on each side and on 10 you have two full waves. If you do match it,
the balun has to be able to handle the voltage. 10 being so wide, some part
of the band may be a better Z for the tuner to handle.
My guess is that the tuner (not) matching these bands will be a bigger
problem than balun survivability. It has to handle an impedance "at the
outer edge" of the Smith chart, so to speak. It may do it for certain
feedline lengths, but not others. I don't know enough about the capability
of these tuners to be more specific 0 except that the few I have seen specs
on specify the Z range over which they can match, so if the Z at the tuner
is outside that range...tilt.

The 40M 1/2 wave dipole (or inverted V) will work fine on 30, 17 & 15 and
probably 12 & 60 where the tuner shouldn't have to strain too much, so to
speak. I've used my 40 M Inverted-V with my MFJ tuner on all these but 60
(and of course 20 & 10). I even managed to load it on 75 with my MFJ tuner
& work the east coast, but that's not a good thing. Just wanted to try.

--
Steve N, K,9;d, c. i My email has no u's.


"Frank MacKenzie-Lamb" wrote in message
...
Hi folks,

I've moved to a country area in central MA and will be putting up a 40m
diople. Considering using a balun with my AT-250 tuner with mt TS-430.
If the tuner can tune in 20 and 10M, will damage be done to the 1:1 balun?
Thanks
NG1I

Or make an off center fed dipole w/ 4:1 balun, which cover some
bands better with a tuner.. ala what radioworks does with
carolina windom. I did work the E44 on 75M using an off center
fed 40M dipole several years back.

I am in leominster, we have tons of people using these locally
and we also have folks having good luck with 160M loops, feeding
it with a 4:1 balun 8-10 feet off a corner. I have not modeled it but
seems pretty good on multiple bands around 20 feet up.

fyi
Jerry AA2T

On Mon, 26 Jan 2004 17:10:41 -0600, "Steve Nosko"
wrote:

Dipoles at even multiples of the main frequency have a problem. The two
bands you mention should be the most difficult to tune with the tuner -
regardless of the balun question. These two bands put the feedpoint at/near
a high impedance feed point on the antenna. On 20 you have two half waves,
one on each side and on 10 you have two full waves. If you do match it,
the balun has to be able to handle the voltage. 10 being so wide, some part
of the band may be a better Z for the tuner to handle.
My guess is that the tuner (not) matching these bands will be a bigger
problem than balun survivability. It has to handle an impedance "at the
outer edge" of the Smith chart, so to speak. It may do it for certain
feedline lengths, but not others. I don't know enough about the capability
of these tuners to be more specific 0 except that the few I have seen specs
on specify the Z range over which they can match, so if the Z at the tuner
is outside that range...tilt.

The 40M 1/2 wave dipole (or inverted V) will work fine on 30, 17 & 15 and
probably 12 & 60 where the tuner shouldn't have to strain too much, so to
speak. I've used my 40 M Inverted-V with my MFJ tuner on all these but 60
(and of course 20 & 10). I even managed to load it on 75 with my MFJ tuner
& work the east coast, but that's not a good thing. Just wanted to try.