ARRL

KM3F

Joined: Thu, Mar 6th 2008, 13:50 Roles: N/A Moderates: N/A

Latest Topics

Topic Created Posts Views Last Activity
RF noise cancelling at VHF frequencies. Nov 20th 2012, 03:59 2 1,644 on 20/11/12
SWEEP testing a radio from the Mike jack. Jun 4th 2012, 04:57 3 914 on 4/6/12
Power Line Interference. Sep 23rd 2011, 01:07 6 2,003 on 11/5/12

Latest Posts

Topic Author Posted On
SWR/Power Meter Irratic K6JMQ 5 days, 4 hours ago
In my opinion you have not received a reply that addresses your issue.
First, your antenna SWR needs to be matched down to within limits as specified by the mfger..
This is why your power meter shows you more power than the radio makes. The reason it the feedline actually sinks power that is being reflected back and forth between the antenna and the radio such that the 'vector sum' the meter reads, registers as more power. The meters don't know any different!
Your internal turner may not have enough range to handle the mis-match.
Turning the power down under these condition would cause the ALC action to never be achieved because the issue is outside the radio such that you did not accomplish anything by lowering the power.
Lowering the power does not affect the basic issue of poor antenna match.
Fix the antenna condition and the issue will clear.
Good luck.
cable one digital box for cable tv KD0NMZ on 5/11/14
That's good to hear.
This is why it's best not to launch into all kinds of filters and other things before knowing what the source is.
Good luck.
cable one digital box for cable tv KD0NMZ on 3/11/14
Your not being quite clear about the boxes.
Are there 3 boxes? Is only one affected? etc.
Has another box been tried?
What bands is the box responding to?
The cable boxes are not supposed to respond the your amateur signals especially at such low powers.
Until the interference mechanism is found no filter will help on a wild guess and a hope basis.
More questions; Is the box remote controllable with a hand unit?
If yes, what is the OFF command from the hand unit, as a start to analyze the possible similarity of command signal to your HF signal or harmonics.
Is the box a plastic type cover without any shielding?
This kind of analysis is needed to find a direction to go in; even then it may not be your responsibly for a box that has design issues you cannot overcome with any amount of effort.
Good luck.
Stuff on 3840 W7WHY on 4/7/14
Late to the party but need some opinion.
.
In contacting our Senators on matters of interference and behavior , I believe their staff and the Senator may not understand the gravity of what is being put forth in a complaint and needs help from some entity that has weight and access to them for consultation on serious matters.
It is difficult enough to get their attention on standard legislation and other matters without going technical on a regulated Hobby they know nothing about..
Is there any format or advice we need to have in pursuing these type of complaints if FCC field office action does not materialize.

Thanks.
Two HF and one VHFwith a triplexer? W1VT on 30/11/13
I know this is an old thread but the subject needs more input.
First there is a multiband antenna on the market now.
Secondly the uses of di or triplexers is not the end all because they do not perform as well as is thought.
Everybody takes them for granted they work without issue.
A check with SWR and power meters on each band between the radio and the plexer will show a significant loss in pass through power and SWR may be high enough to cause transceiver power fold back such that nothing works very well..
Bottom line is not to use them unless you accept the results.
The other answer is to build them custom tuned to each band of use using low loss coaxial designs and adjustable tuned traps.
The ones available are cheap low grade broad band designs for the cost.
Good luck.

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