NMO34 with the W640 (64" whip) vs NMO-27 vs CWB-27

[serial14]

Does anybody have any current supplier links to the CW27 model family mentioned? I'm only finding things for the C27 model family. As noted above a key difference seems to be a 49" whip vs the 67" whip on the CW line.

Given the radio choices available these days, as well as the good band conditions, a mobile antenna capable of 11M and 10M is pretty attractive.

 

[prcguy]

Does anybody have any current supplier links to the CW27 model family mentioned? I'm only finding things for the C27 model family. As noted above a key difference seems to be a 49" whip vs the 67" whip on the CW line.

Given the radio choices available these days, as well as the good band conditions, a mobile antenna capable of 11M and 10M is pretty attractive.

CW27 has been out of production for awhile but some suppliers may have a few in stock or they show up on ebay.

 

[prcguy]

Does anybody have any current supplier links to the CW27 model family mentioned? I'm only finding things for the C27 model family. As noted above a key difference seems to be a 49" whip vs the 67" whip on the CW line.

Given the radio choices available these days, as well as the good band conditions, a mobile antenna capable of 11M and 10M is pretty attractive.

The most important difference is the broad banding components inside the loading coil. I finally found a picture of all the stuff in there.

 

[serial14]

The most important difference is the broad banding components inside the loading coil. I finally found a picture of all the stuff in there.

That answers my next question of the bases being the same or different.

 

[RFI-EMI-GUY]

The most important difference is the broad banding components inside the loading coil. I finally found a picture of all the stuff in there.

Was there a patent assigned for that?

 

[prcguy]

Was there a patent assigned for that?

You would have to find some old Antenex or Laird catalogs and look in the WB section. It used to take about 5yrs to get a patent so I might expect to see a "patent pending" from 15-20yrs ago or whenever they first came out.

CHP bought a boatload of the Antenex/Laird WB 39-46MHz versions (model WPC39SOB-001) then later went with a similar model from Panorama Antennas. I've had the Panorama apart and its a completely different design with a tapped loading coil then an array of surface mount capacitors on a circuit board from ground to a point on the loading coil then the base of the whip.

 

[prcguy]

I stuck a CW27 with a 5" mag mount on the hood of my Jeep and graphed the VSWR with cursers at roughly the 2.0:1 points of 25.9 and 31.8MHz. Sorry, this meter only has one curser so there are two pics showing the upper and lower edges. The truck hood is not that big and I don't think the magnet was that great with the magnet being recessed in the housing and it had a thick plastic sheet over the magnet end. I noticed the VSWR changed a bit when I handled the meter telling me the ground coupling was not good enough. Anyway this gives you an idea of what the antenna can do for CB and 10m.

 

[RFI-EMI-GUY]

• Wide-banded mobile antenna​

  
  Patent number: 5604507
  
  Abstract: A wide-banded mobile antenna enhancing signal transmission by broadening the effective transmission bandwidth. The wide-banded mobile antenna is interchangeable with currently existing mobile antennas as the two use connectors established by industry. An antenna matching network is situated within a protective housing having a metal shield. A toroidal inductor is serially connected with the antenna and creates a parasitic capacitance with the metal shield. The resulting network, including the antenna, is tuned. An antenna compensating network increases the bandwidth of the antenna with a parallel resonance network. The parallel resonance network has a capacitor and an inductor connected in parallel to the antenna and each other. The parallel resonance inductor is oriented so that the fields it generates are perpendicular to those of the antenna and the matching inductor to prevent coupling between the inductors.
  
  Type: Grant
  
  Filed: February 28, 1996
  
  Date of Patent: February 18, 1997
  
  Assignee: Antenex, Inc.
  
  Inventor: Wayne R. Openlander
• 
  
• 
  

 

[RFI-EMI-GUY]

See Fig 8B 8A in the patent. Looks very much like your sweep

 

[RFI-EMI-GUY]

ULS License - Amateur License - W9NZB - OPENLANDER, WAYNE R

 

[prcguy]

• Wide-banded mobile antenna​

  
  Patent number: 5604507
  
  Abstract: A wide-banded mobile antenna enhancing signal transmission by broadening the effective transmission bandwidth. The wide-banded mobile antenna is interchangeable with currently existing mobile antennas as the two use connectors established by industry. An antenna matching network is situated within a protective housing having a metal shield. A toroidal inductor is serially connected with the antenna and creates a parasitic capacitance with the metal shield. The resulting network, including the antenna, is tuned. An antenna compensating network increases the bandwidth of the antenna with a parallel resonance network. The parallel resonance network has a capacitor and an inductor connected in parallel to the antenna and each other. The parallel resonance inductor is oriented so that the fields it generates are perpendicular to those of the antenna and the matching inductor to prevent coupling between the inductors.
  
  Type: Grant
  
  Filed: February 28, 1996
  
  Date of Patent: February 18, 1997
  
  Assignee: Antenex, Inc.
  
  Inventor: Wayne R. Openlander
• 
  
• 
  

The CHP antenna I have has a metal looking base cover where all my CW-27s are plastic. The early commercial band versions look just like my CW-27s but the CHP and later versions look completely different.

Here is a CHP picture I snagged off ebay. Compare that with my CW-27 pics in post #11.

 

[RFI-EMI-GUY]

As far as the shielding, the orientation of the inductors and use of toroidial is supposed to minimize mutual inductance. I suppose that shielding etc., is the secret sauce of making them work.

The patent described another device similar to Motorola HAB1004A of which I have two of these that look to be 37-49 33 to 43 MHz. Meant to be mounted close to base of a whip (87.25 78.25 inches?). They are assembled in what looks almost like a soup can.

 

[RFI-EMI-GUY]

President Electronics has a couple antennas on their UK site for their "ham radios" namely Colorado 800WB. Sadly not an NMO mount. Has graphite whip? Is this just an expensive dummy load?

 

[prcguy]

President Electronics has a couple antennas on their UK site for their "ham radios" namely Colorado 800WB. Sadly not an NMO mount. Has graphite whip? Is this just an expensive dummy load?

View attachment 172421

I see some outright lies on this one. Its very difficult to broad band an antenna past a certain extent and not loose radiation efficiency. Laird, Panorama, Motorola and maybe others have done it with L/C combinations that work and I doubt President has done this in the in the tiny enclosure on this antenna. They also claim 5dBi gain which would be 2.86dBd gain or 2.86dB more than a full size 18ft tall dipole. How is this possible? They also state this is a 5/8 wave antenna but that doesn't buy you anything in a package this small. If you compare a 1/4 wave or 1/2 wave or 5/8 wave in a package that is less than 1/8 wavelength tall there is really no difference and if anything the 1/2 or 5/8 may have more loss over a 1/4 wave of the same length.

So if you buy this antenna and it doesn't produce 5dBi of gain or even 0dBi gain, can you sue the company for false advertising? I think that should be an option.

 

[RFI-EMI-GUY]

I see some outright lies on this one. Its very difficult to broad band an antenna past a certain extent and not loose radiation efficiency. Laird, Panorama, Motorola and maybe others have done it with L/C combinations that work and I doubt President has done this in the in the tiny enclosure on this antenna. They also claim 5dBi gain which would be 2.86dBd gain or 2.86dB more than a full size 18ft tall dipole. How is this possible? They also state this is a 5/8 wave antenna but that doesn't buy you anything in a package this small. If you compare a 1/4 wave or 1/2 wave or 5/8 wave in a package that is less than 1/8 wavelength tall there is really no difference and if anything the 1/2 or 5/8 may have more loss over a 1/4 wave of the same length.

So if you buy this antenna and it doesn't produce 5dBi of gain or even 0dBi gain, can you sue the company for false advertising? I think that should be an option.

That lofty gain might be the excess, albeit brief, thermal energy emitted as the carbon fiber burns up with my 100W FM SYNTOR X9K.

I found a video with a tear down and the coil has only a simple tap. An autotransformer. PRESIDENT US seems to be a wealthy company in Naples Florida. Maybe a lawyer will take them on!

 

[prcguy]

That lofty gain might be the excess, albeit brief, thermal energy emitted as the carbon fiber burns up with my 100W FM SYNTOR X9K.

I found a video with a tear down and the coil has only a simple tap. An autotransformer. PRESIDENT US seems to be a wealthy company in Naples Florida. Maybe a lawyer will take them on!

So they are measuring gain in a brief release of energy from nuclear fusion induced by a SyntorX. Wonder if there is enough time during the event to get our your callsign? I'll be looking for the video showing the coil.

 

[RFI-EMI-GUY]

So they are measuring gain in a brief release of energy from nuclear fusion induced by a SyntorX. Wonder if there is enough time during the event to get our your callsign? I'll be looking for the video showing the coil.

I think it is the unboxing video.

 

[jcrmadden]

Of the three mentioned I only have Laird CW27 which is the chrome version of the CWB27 which is black. This is the wide band 26.8 to 29.7MHz with no tuning and 67.5" whip. If you put the 67.5" whip on a Larsen NMO34 coil it will work a little better than a stock Larsen NMO27 with 49" whip and depending on how long the whip is after tuning it may equal or slightly out perform a CW27 wide band. Not sure if the CW27 series has any or much loss due to the complicated circuit in the base and that's what might give an edge to the long whip NMO34.

The listing on Antenna Farm says the NMO34 is for 34-40 MHz... Larsen NMO34

Does the pairing with the W640 whip change that?

 

[prcguy]

The listing on Antenna Farm says the NMO34 is for 34-40 MHz... Larsen NMO34

Does the pairing with the W640 whip change that?

Yes, using a higher freq loading coil with less turns then make up with a longer whip to resonate at 27MHz. Less coil = less loss, mo betta.

 

[slowmover]

The listing on Antenna Farm says the NMO34 is for 34-40 MHz... Larsen NMO34

Does the pairing with the W640 whip change that?

It’ll look great on that Yukon.

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