My 40M beam works only intermittently. Typically under normal
conditions, the received signals are weak and the SWR is very high.
If I rotate the antenna, it "comes alive" in some directions and works
fine for a while, then dies again. In all cases, if I transmit into it
with a KW is comes alive and works fine for a while (few minutes) and
then dies again. A single dit will fix it. 100W does not do it.

I replaced the coax which runs around the rotator and it made no
difference. I just recently learned that a local friend also has an
intermittent antenna which can be restored by transmitting a KW into it.

Is this a common problem? is there a generic solution? Any hints
would be appreciated. Note that it is not too easy when up on the tower
to jiggle things while someone on the ground tries to watch the SWR and
shout back and forth. We tried that when we replaced the coax.

Thanks!

Bob W8ERD

On Apr 2, 11:52 am, Bob Dixon wrote:
My 40M beam works only intermittently. Typically under normal
conditions, the received signals are weak and the SWR is very high.
If I rotate the antenna, it "comes alive" in some directions and works
fine for a while, then dies again. In all cases, if I transmit into it
with a KW is comes alive and works fine for a while (few minutes) and
then dies again. A single dit will fix it. 100W does not do it.

I replaced the coax which runs around the rotator and it made no
difference. I just recently learned that a local friend also has an
intermittent antenna which can be restored by transmitting a KW into it.

Is this a common problem? is there a generic solution? Any hints
would be appreciated. Note that it is not too easy when up on the tower
to jiggle things while someone on the ground tries to watch the SWR and
shout back and forth. We tried that when we replaced the coax.

Thanks!

Bob W8ERD

What you have is an electrical connection that is physically an
electrical
circuit but has a corrosion build up at the joint. A poorly connected
pressure
on the coax is often the cause. Change to a soldered connection and
make
sure the connection is tight. If you have twisted wires on the antenna
put
wire nuts on them.to increase pressure on the joint.
The antenna itself can create similar problems if you have not used a
conductive grease
at telescopic joint connections
Have fun
Art

what brand/model? the 40-2cd has a known problem with the loading coil
connections becoming intermittant that gives symptoms just like that. other
loading coils, baluns, or matching section connections may do the same thing
on other models.

"Bob Dixon" wrote in message
...
My 40M beam works only intermittently. Typically under normal
conditions, the received signals are weak and the SWR is very high.
If I rotate the antenna, it "comes alive" in some directions and works
fine for a while, then dies again. In all cases, if I transmit into it
with a KW is comes alive and works fine for a while (few minutes) and
then dies again. A single dit will fix it. 100W does not do it.

I replaced the coax which runs around the rotator and it made no
difference. I just recently learned that a local friend also has an
intermittent antenna which can be restored by transmitting a KW into it.

Is this a common problem? is there a generic solution? Any hints
would be appreciated. Note that it is not too easy when up on the tower
to jiggle things while someone on the ground tries to watch the SWR and
shout back and forth. We tried that when we replaced the coax.

Thanks!

Bob W8ERD

Dave wrote:
what brand/model? the 40-2cd has a known problem with the loading coil
connections becoming intermittant that gives symptoms just like that. other
loading coils, baluns, or matching section connections may do the same thing
on other models.

"Bob Dixon" wrote in message
...
My 40M beam works only intermittently. Typically under normal
conditions, the received signals are weak and the SWR is very high.
If I rotate the antenna, it "comes alive" in some directions and works
fine for a while, then dies again. In all cases, if I transmit into it
with a KW is comes alive and works fine for a while (few minutes) and
then dies again. A single dit will fix it. 100W does not do it.

I replaced the coax which runs around the rotator and it made no
difference. I just recently learned that a local friend also has an
intermittent antenna which can be restored by transmitting a KW into it.

Is this a common problem? is there a generic solution? Any hints
would be appreciated. Note that it is not too easy when up on the tower
to jiggle things while someone on the ground tries to watch the SWR and
shout back and forth. We tried that when we replaced the coax.


This antenna is probably going to have to come down for a look-see. I
would suspect something very near the area closest to the mast, but
those coils are a suspect too.

Running high power into the antenna might fix it, or might burn a coil
or other part up. I guess the rationale was to heat up an intermittent
connection, and "weld" it back together. Hoo boy, I'd pass on that.

Setting the antenna down will allow you to do some maintenance on the
whole thing. If you have one intermittent, problems can show up in other
places too, so its time to bite the bullet. Certainly not pleasant with
a 40 meter beam.

- 73 de Mike N3LI -

Dear Bob: Great to hear from another of Kraus' boys. I had a similar
problem with a large LPDA after it had been up for a while. Its pattern
went backwards. It had to be taken down whereupon a loose connection was
found. So many things to go wrong.

At least better weather is coming. 73, Mac N8TT
--
J. McLaughlin; Michigan, USA
Home:
"Michael Coslo" wrote in message
...
Dave wrote:
what brand/model? the 40-2cd has a known problem with the loading coil
connections becoming intermittant that gives symptoms just like that.
other loading coils, baluns, or matching section connections may do the
same thing on other models.

"Bob Dixon" wrote in message
...
My 40M beam works only intermittently. Typically under normal
conditions, the received signals are weak and the SWR is very high.
If I rotate the antenna, it "comes alive" in some directions and works
fine for a while, then dies again. In all cases, if I transmit into it
with a KW is comes alive and works fine for a while (few minutes) and
then dies again. A single dit will fix it. 100W does not do it.

I replaced the coax which runs around the rotator and it made no
difference. I just recently learned that a local friend also has an
intermittent antenna which can be restored by transmitting a KW into it.

Is this a common problem? is there a generic solution? Any hints
would be appreciated. Note that it is not too easy when up on the tower
to jiggle things while someone on the ground tries to watch the SWR and
shout back and forth. We tried that when we replaced the coax.


This antenna is probably going to have to come down for a look-see. I
would suspect something very near the area closest to the mast, but those
coils are a suspect too.

Running high power into the antenna might fix it, or might burn a coil or
other part up. I guess the rationale was to heat up an intermittent
connection, and "weld" it back together. Hoo boy, I'd pass on that.

Setting the antenna down will allow you to do some maintenance on the
whole thing. If you have one intermittent, problems can show up in other
places too, so its time to bite the bullet. Certainly not pleasant with a
40 meter beam.

- 73 de Mike N3LI -

On Apr 3, 6:13*pm, "J. Mc Laughlin" wrote:
Dear Bob: *Great to hear from another of Kraus' boys. *I had a similar
problem with a large LPDA after it had been up for a while. *Its pattern
went backwards. *It had to be taken down whereupon a loose connection was
found. *So many things to go wrong.

At least better weather is coming. * 73, * Mac * *N8TT
--
J. McLaughlin; *Michigan, USA
Home: "Michael Coslo" wrote in message

...



Dave wrote:
what brand/model? *the 40-2cd has a known problem with the loading coil
connections becoming intermittant that gives symptoms just like that.
other loading coils, baluns, or matching section connections may do the
same thing on other models.

"Bob Dixon" wrote in message
...
My 40M beam works only intermittently. *Typically under normal
conditions, the received signals are weak and the SWR is very high.
If I rotate the antenna, it "comes alive" in some directions and works
fine for a while, then dies again. *In all cases, if I transmit into it
with a KW is comes alive and works fine for a while (few minutes) and
then dies again. A single dit will fix it. 100W does not do it.

I replaced the coax which runs around the rotator and it made no
difference. *I just recently learned that a local friend also has an
intermittent antenna which can be restored by transmitting a KW into it.

"JIMMIE" wrote in message
...
On Apr 3, 6:13 pm, "J. Mc Laughlin" wrote:
Dear Bob: Great to hear from another of Kraus' boys. I had a similar
problem with a large LPDA after it had been up for a while. Its pattern
went backwards. It had to be taken down whereupon a loose connection was
found. So many things to go wrong.

At least better weather is coming. 73, Mac N8TT
--
J. McLaughlin; Michigan, USA
Home: "Michael Coslo" wrote in message

...



Dave wrote:
what brand/model? the 40-2cd has a known problem with the loading coil
connections becoming intermittant that gives symptoms just like that.
other loading coils, baluns, or matching section connections may do the
same thing on other models.

"Bob Dixon" wrote in message
...
My 40M beam works only intermittently. Typically under normal
conditions, the received signals are weak and the SWR is very high.
If I rotate the antenna, it "comes alive" in some directions and works
fine for a while, then dies again. In all cases, if I transmit into it
with a KW is comes alive and works fine for a while (few minutes) and
then dies again. A single dit will fix it. 100W does not do it.

I replaced the coax which runs around the rotator and it made no
difference. I just recently learned that a local friend also has an
intermittent antenna which can be restored by transmitting a KW into
it.

Is this a common problem? is there a generic solution? Any hints
would be appreciated. Note that it is not too easy when up on the
tower
to jiggle things while someone on the ground tries to watch the SWR
and
shout back and forth. We tried that when we replaced the coax.

This antenna is probably going to have to come down for a look-see. I
would suspect something very near the area closest to the mast, but
those
coils are a suspect too.

Running high power into the antenna might fix it, or might burn a coil
or
other part up. I guess the rationale was to heat up an intermittent
connection, and "weld" it back together. Hoo boy, I'd pass on that.

Setting the antenna down will allow you to do some maintenance on the
whole thing. If you have one intermittent, problems can show up in other
places too, so its time to bite the bullet. Certainly not pleasant with
a
40 meter beam.

- 73 de Mike N3LI -- Hide quoted text -

- Show quoted text -

I had a problem like that with a little Yagi for 10M I bought at a
hamfest. The Aluminum rod for the gamma match was riveted to the coax
connector. Repair was to replace the Al tube with a brass one and a
new connector was soldered to the tube.


Jimmie

About the same here with a CushCraft 2m beam. Very intermittent. The SO239
shell was supposed to make contact by virtue of being screwed into an
aluminum angle iron. It didn't. Replaced the SO239.

Tam/WB2TT