• Effective immediately we will be deleting, without notice, any negative threads or posts that deal with the use of encryption and streaming of scanner audio.

    We've noticed a huge increase in rants and negative posts that revolve around agencies going to encryption due to the broadcasting of scanner audio on the internet. It's now worn out and continues to be the same recycled rants. These rants hijack the threads and derail the conversation. They no longer have a place anywhere on this forum other than in the designated threads in the Rants forum in the Tavern.

    If you violate these guidelines your post will be deleted without notice and an infraction will be issued. We are not against discussion of this issue. You just need to do it in the right place. For example:
    https://forums.radioreference.com/rants/224104-official-thread-live-audio-feeds-scanners-wait-encryption.html

Here is a challange

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n4yek

Member
Joined
Apr 20, 2004
Messages
2,479
Location
Newport, Tennessee
I am trying to figure out the optimal length of a single whip to cover the following frequecies to the best it possibly can:
42 Mhz
72 Mhz
150 - 173 Mhz
460 Mhz
850 - 860 Mhz.

So far I am at 33 inches with decent results, but the 42 MHZ is significantly degraded. Any others out there want to try and find the optimal length?

I know a multi band antenna would be preferred but I am just playing around here.

Take care.
 

af5rn

Member
Joined
Apr 4, 2008
Messages
1,059
Location
N. Tex / S. Fla
26.872 inches to resonate the middle frequency of 418mHz.

You can recalculate and go up or down to give greater weight to either end of your spectrum, depending on what band is most important to you.
 

digitalanalog

Member
Joined
May 18, 2007
Messages
401
There really is No optimal length Single whip antenna that will cover such a wide spectrum.

you might want to (if your just toying around with homemade stuff like i do) try making a couple J antenna's out of old stuff laying around.

Just a thought...............................

There are a bunch of J tenna calculators on the web to assist in length,spacing and details
just search it.

Good luck, and let us know what you get
 

prcguy

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Joined
Jun 30, 2006
Messages
7,830
Location
So Cal - Richardson, TX - Tewksbury, MA
You can calculate until the batteries run out in your calculator before you find the answer to that one. Even if you find some length that is resonant everywhere, the impedance may be impossible to match to coax and at higher frequencies the radiation pattern may be dead at the horizon with lobes pointing at the moon.
prcguy
digitalanalog said:
There really is No optimal length Single whip antenna that will cover such a wide spectrum.

you might want to (if your just toying around with homemade stuff like i do) try making a couple J antenna's out of old stuff laying around.

Just a thought...............................

There are a bunch of J tenna calculators on the web to assist in length,spacing and details
just search it.

Good luck, and let us know what you get
 
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