On 8/21/2013 10:51 AM, RShirbroun@newportlabs.com wrote:
I didn't get any comments or suggestions to my previous post, so I'll try again.
If this is a dumb question, feel free to tell me!
I have just erected a new HDBX 40 in place of my 30 year old HBX 48,
sacrificing 8' of height to gain some strength and load capacity (and peace of
mind!). The stock rotator plate allows 2' of mast below the top plate and I
will be using the heavy duty Yaesu thrust bearing (along with the Yaesu heavy
duty 2800 rotator plus the absorber plate). I have added steel angle braces
to reinforce the rotator plate.
My opinion...The mast is plenty strong, (far more than needed) but I
have my doubts about thr tower to reliably stand that much load. That
series of towers are designed for relatively light loads and low torque
conditions. They are stamped metal that is riveted and I believe the
load plus leverage of the mast exceeds the tower ratings by a
substantial margin.
The 10' boom limitation is to limit the torque.
73 and good luck,
Roger (K8RI)
I'm looking at using a 15' chrome/steel 2" mast (in place of my previous 9'
mast), so 13' of the mast would extend above the tower. The mast would support
a TX38 tribander just above the top plate, a 6 m beam half-way up, and a 40m
rotatable dipole near the top, 12' above the top tower plate and the thrust
bearing. The mast, of course, is very heavy, weighing around 75lbs. The
tribander weighs 40lbs and with 5 ft2 surface area; the 6 m. beam weighs 10lbs
with 1.5 ft2; the dipole weighs 10lbs and is 0.5 ft2.
Is this too much mast for this tower? (BTW - I'm aware the boom length
exceeds the 10' maximum for this tower, but the HBX 48 handled a similar
tribander for 30 years, with occasional severe ice-loading, without any
problems.)
Thanks and 73,
Randy, ND0C
________________________________
This e-mail and any files transmitted with it are confidential and intended
solely for the use of the individual or entity to whom they are addressed. If
you have received this e-mail in error please notify the system manager:
postmaster@merial.com This e-mail and its attachments have been scanned for the
presence of computer viruses, however it is always advisable to run a virus
check on e-mails and attachments before opening them.
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|