RadioReference on Facebook   RadioReference on Twitter   RadioReference Blog
 

Go Back   The RadioReference.com Forums > Topic Specific Forums > Antennas and Associated Hardware > Scanner / Receiver Antennas

Scanner / Receiver Antennas For discussion of any type of receiving antenna used by a scanner or receiver base, mobile or handheld.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1 (permalink)  
Old 11-15-2011, 8:24 PM
123 123 is offline
Member
  Audio Feed Provider
Audio Feed Provider
 
Join Date: Oct 2003
Location: Chattanooga, TN.
Posts: 549
Default Double discone

Any of you guys ever tried one of these? I have a diamond right now 40ft in the air. Mainly monitor mil air....

Thoughts or experiences ?
__________________
Get your Mil discone on!
Reply With Quote
Sponsored links
  #2 (permalink)  
Old 11-16-2011, 9:01 AM
Member
  Premium Subscriber
Premium Subscriber
 
Join Date: Jun 2006
Posts: 3,423
Default

Save your money. I bought a Nevada Double Discone and a RS Discone works better over a wider frequency range.

Even the name is made up, its not a Double Discone, its a Bicone or Biconical but without the needed matching network at the feedpoint.

I have a couple of real Bicone antennas and they are rated for around a 3 to 1 or 3 to 1 frequency range compared to a Discone which is rated for about 8 to 1 frequency range if properly designed.

My Nevada POS has a good match around 2m but thats about it compared to any other scanner type Discones which have a useable match from around 100 to 800MHz.

For a real Bicone check out the Harris RF-9070 which is rated for about 90 to 470MHz with some slight degradation but in reality it seems to have some gain within its full spec 100 to 400MHz range. Unfortunately it costs a lot of money due to the engineering and complicated matching network in the hub. Here is a link to a spec sheet for the Harris, otherwise there are no good Bicone antennas for a cheap price except for imposters like the Nevada or the rare military surplus find like my Harris RF-7090.

http://rf.harris.com/media/RF-9070_tcm26-9211.pdf

And another thing, the Harris is about 5ft tall and 5ft wide and only covers 90 to 470Mhz at its maximum ratings. I have another military Bicone that covers 30 to 90MHz and its about 18ft tall and 6ft wide where the Nevada is maybe 4ft tall and 2ft wide. How do they get 25 to 1300MHz coverage from something that small? They lie, that's how!
prcguy

Last edited by prcguy; 11-16-2011 at 9:37 AM..
Reply With Quote
  #3 (permalink)  
Old 11-16-2011, 8:15 PM
Member
   
Join Date: Feb 2009
Location: cape cod
Posts: 17
Default

prcguy
to convert the Double Discone back to a Discone,
what size? solid disk should i use.
thanks
Reply With Quote
  #4 (permalink)  
Old 11-16-2011, 10:04 PM
Member
  Premium Subscriber
Premium Subscriber
 
Join Date: Jun 2006
Posts: 3,423
Default

It looks very simple to make one and possibly two Discones from a Nevada Double cone thingee. I was considering the same thing but have enough Discones at the moment.

I remember the dimensions for a Discone is the skirt is an equilateral triangle with the length of one side slightly longer than 1/4 wavelength at the lowest frequency and the disc diameter is between .67 and .7 of the skirt length. Then the spacing between the disc and skirt will affect impedance and VSWR.

I would make the disc from aluminum sheet metal around .063 thick and hopefully the stud on top of the hub assy will space it right for a good match.
prcguy





Quote:
Originally Posted by 2531 View Post
prcguy
to convert the Double Discone back to a Discone,
what size? solid disk should i use.
thanks
Reply With Quote
  #5 (permalink)  
Old 11-16-2011, 10:27 PM
Member
   
Join Date: Feb 2009
Location: cape cod
Posts: 17
Default

Thanks prcguy!
Reply With Quote
Sponsored links
  #6 (permalink)  
Old 11-17-2011, 10:02 AM
zguy1243's Avatar
Member
  Amateur Radio Operator
Amateur Radio
 
Join Date: Apr 2006
Location: Calhoun Georgia
Posts: 877
Default

Quote:
Originally Posted by 123 View Post
Any of you guys ever tried one of these? I have a diamond right now 40ft in the air. Mainly monitor mil air....

Thoughts or experiences ?
Get you a Kreco discone. I know you wanted the VHF performance with the UHF too. (I guess why you stopped using the AT-197?) The Kreco has the great build quality like the AT-197 did but is a bit more broad banded. Kreco has a number of different models that really work well and built very nice. The price is acceptable too for hobby use.....
Reply With Quote
  #7 (permalink)  
Old 11-17-2011, 10:43 AM
ridgescan's Avatar
Member
  Shack Photos
Shack photos
 
Join Date: Apr 2008
Location: San Francisco, Ca.
Posts: 3,578
Default

I saw that DDiscone at HRO they want $150 for it-I still have a skirt from an old discone here I was thinking I could just bolt that to the top of my D130j lol and have the same thing.
__________________
Unidens BC785D,BC350A on a Diamond D130J @50'
'54 Hallicrafters SX-88 #127; Icoms R71A&R75, on a Wellbrook ALA1530s+ loop @ 50'
RS Pro 2066 in truck to glass mount tribander
Reply With Quote
  #8 (permalink)  
Old 11-17-2011, 1:05 PM
Member
  Premium Subscriber
Premium Subscriber
 
Join Date: Jun 2006
Posts: 3,423
Default

Yes, you would have the same thing but I think it would be going backwards from a Discone.

BTW, there was a new KRECO 100-800MHz Discone missing the top hat radials on EBay recently. I got it for cheap and already received replacement parts from KRECO.
prcguy


Quote:
Originally Posted by ridgescan View Post
I saw that DDiscone at HRO they want $150 for it-I still have a skirt from an old discone here I was thinking I could just bolt that to the top of my D130j lol and have the same thing.
Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -5. The time now is 5:53 AM.


Powered by vBulletin® Version 3.8.2
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
All information here is Copyright 2012 by RadioReference.com LLC and Lindsay C. Blanton III.Ad Management by RedTyger
Copyright 2011 by RadioReference.com LLC Privacy Policy  |  Terms and Conditions