starman wrote:
big boy now wrote:

A week ago i placed my order for a Wellbrook ALA330S active antenna
loop...
Well the ALA330S arrived today
first impression of the antenna is packaging was spot on no
problems....
i carefully un packed the antenna to inspect the parts included
with the
antenna. my first findings are as follows. the loop its self looks
well
made. but for the mounting bracket that is included anybody who has
brought
a wellbrook loop will agree this bracket fixes to the bottom of the
antenna
by use of two screws. the mounting plate only has a 1 inch tube
coming from
the mounting plate this is to allow it to be fitted inside a pole
of the
correct internal diameter and a hole drilled through and screwed
together
this mounting plate in my opinion needs to be re designed with a
longer tube
fitted to the mounting plate .....

How well do you think it would stand up to some rough winter weather
with icing and strong winds?


The antenna should be pretty resilient once you have it mounted. As I
recall, Wellbrook does recommend that, after attaching the base of the
loop to a post, rotor, etc., you should add some improvised vertical
supports to support the upper portion of the loop in the event of high
winds. I doubt it would be hard to add this extra support.

The way I have the antenna situated is unusual, I think. I have it on
the end of a horizontal mast extending away from my building. The *top*
of the loop is actually attached to the mast via some clamps and
protective rubber inserts. The clamps hold the loop firmly, but not so
tightly that the antenna can't 'give' in the face of strong winds. The
base of the loop, with the coax attached, isn't mounted to anything,
but the coax itself provides it with a bit of weight and added
stability.

I obviously could have mounted the loop differently, and could
certainly have attached it via its base to the horizontal mast I'm
using, provided I also gave it some vertical support for wind
protection. However, I thought that attaching the upper portion of the
loop to the mast while leaving the bottom free to shift a bit with the
wind would provide better long term protection, and after a few months
I feel pretty good about this arrangement. Because the loop is visible
out my kitchen window, I've monitored its condition very carefully and
everything's working out just fine. In fact, over the last couple of
days we've had very strong winds and these have not stressed the loop
*at all*.

Steve

wrote:

starman wrote:

How well do you think it would stand up to some rough winter weather
with icing and strong winds?


The antenna should be pretty resilient once you have it mounted. As I
recall, Wellbrook does recommend that, after attaching the base of the
loop to a post, rotor, etc., you should add some improvised vertical
supports to support the upper portion of the loop in the event of high
winds. I doubt it would be hard to add this extra support.

The way I have the antenna situated is unusual, I think. I have it on
the end of a horizontal mast extending away from my building. The *top*
of the loop is actually attached to the mast via some clamps and
protective rubber inserts. The clamps hold the loop firmly, but not so
tightly that the antenna can't 'give' in the face of strong winds. The
base of the loop, with the coax attached, isn't mounted to anything,
but the coax itself provides it with a bit of weight and added
stability.

I obviously could have mounted the loop differently, and could
certainly have attached it via its base to the horizontal mast I'm
using, provided I also gave it some vertical support for wind
protection. However, I thought that attaching the upper portion of the
loop to the mast while leaving the bottom free to shift a bit with the
wind would provide better long term protection, and after a few months
I feel pretty good about this arrangement. Because the loop is visible
out my kitchen window, I've monitored its condition very carefully and
everything's working out just fine. In fact, over the last couple of
days we've had very strong winds and these have not stressed the loop
*at all*.

I have this vision of the loop snapping off at the base (standard
mounting) when it's loaded with ice in a high wind. It's not clear to me
how you would provide more vertical support at the top of the loop
without interfering with it's ability to rotate (with a rotor).


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I have this vision of the loop snapping off at the base (standard
mounting) when it's loaded with ice in a high wind. It's not clear to
me
how you would provide more vertical support at the top of the loop
without interfering with it's ability to rotate (with a rotor).


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Well, it isn't always mounted on a rotor. I didn't use a rotor because
the antenna's performance seems pretty omnidirectional on the
frequencies that interest me. However, I don't spend a lot of time on
MW either, and anyone who does should definitely use a rotor.

My sense is that the antenna is quite strong and there's nothing on it
to really 'catch' the wind. If you didn't provide additional support, I
doubt that the antenna would ever sustain wind damage. However, if you
had it right in front of you and had an hour or two to think about it,
I'm sure you could improvise some sort of additional support. You'd
probably have fun doing it, too!

Steve

wrote:

I have this vision of the loop snapping off at the base (standard
mounting) when it's loaded with ice in a high wind. It's not clear to
me
how you would provide more vertical support at the top of the loop
without interfering with it's ability to rotate (with a rotor).

Well, it isn't always mounted on a rotor. I didn't use a rotor because
the antenna's performance seems pretty omnidirectional on the
frequencies that interest me. However, I don't spend a lot of time on
MW either, and anyone who does should definitely use a rotor.

My sense is that the antenna is quite strong and there's nothing on it
to really 'catch' the wind. If you didn't provide additional support, I
doubt that the antenna would ever sustain wind damage. However, if you
had it right in front of you and had an hour or two to think about it,
I'm sure you could improvise some sort of additional support. You'd
probably have fun doing it, too!

One of the nice features of the Wellbrook is being able to mount it with
a dual axis rotor so you can fine tune the reception angle. It's an
expensive option but that's what I would do to get the most out of it. I
wonder if anyone knows the circuit design for the loop's pre-amp? That's
probably what makes it perform so well.

starman wrote:


One of the nice features of the Wellbrook is being able to mount it with
a dual axis rotor so you can fine tune the reception angle. It's an
expensive option but that's what I would do to get the most out of it. I
wonder if anyone knows the circuit design for the loop's pre-amp? That's
probably what makes it perform so well.

The Wellbrook preamp is potted to make it tougher for someone to swipe
the design.

I think major reasons it performs so well include the fact loop antennas
are less susceptible to noise, and they were able to design their
antennas as complete systems.

If you'd like to experiment with preamps, I suggest checking ebay or
your local hamfests for preamps made by companies like Avantek, WJ, or
the company known at various times as Norlin, Aiken, ACL, and Applied
Communications. Typically, they'll be low noise designs with plenty of
dynamic range. I often find these at the flea at MIT for anywhere
between $10 and $40.

I also tried an ARR brand preamp, (about $50 new) and it performed well,
but it got taken out by the first lightning strike in the neighborhood.

As for being able to rotate the Wellbrook loops, my understanding is
you're not likely to notice a difference on HF bands.

"Mark S. Holden" wrote:

starman wrote:


One of the nice features of the Wellbrook is being able to mount it with
a dual axis rotor so you can fine tune the reception angle. It's an
expensive option but that's what I would do to get the most out of it. I
wonder if anyone knows the circuit design for the loop's pre-amp? That's
probably what makes it perform so well.

The Wellbrook preamp is potted to make it tougher for someone to swipe
the design.

And any competent electronics outfit has already done so, if they were
interested in the design.

I've worked for numerous firms over the years and the number of competitor
products coming through the door for study and evaluation was astounding.

If it hasn't been mentioned already, there was a review in the 2002 Passport
regarding this antenna and the dual axis rotor scheme by Chuck Rippel. It may
have appeared in other additions as well.

dxAce
Michigan
USA

"Mark S. Holden" wrote:

starman wrote:


One of the nice features of the Wellbrook is being able to mount it with
a dual axis rotor so you can fine tune the reception angle. It's an
expensive option but that's what I would do to get the most out of it. I
wonder if anyone knows the circuit design for the loop's pre-amp? That's
probably what makes it perform so well.

The Wellbrook preamp is potted to make it tougher for someone to swipe
the design.

That's a challenge I would enjoy. Anyone want to donate their Wellbrook
loop preamp for micro-disection?

I think major reasons it performs so well include the fact loop antennas
are less susceptible to noise, and they were able to design their
antennas as complete systems.

If you'd like to experiment with preamps, I suggest checking ebay or
your local hamfests for preamps made by companies like Avantek, WJ, or
the company known at various times as Norlin, Aiken, ACL, and Applied
Communications. Typically, they'll be low noise designs with plenty of
dynamic range. I often find these at the flea at MIT for anywhere
between $10 and $40.

I also tried an ARR brand preamp, (about $50 new) and it performed well,
but it got taken out by the first lightning strike in the neighborhood.

As for being able to rotate the Wellbrook loops, my understanding is
you're not likely to notice a difference on HF bands.

I thought so too but I've seen of reports to the contrary.


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