~Toughbooktalk~

It's all guesstimating anyway. I can't be too precise since I'm not sure if the little cap on the end adds to the length. It would probably be easier to find which carrier was originally locked to the WWAN in that toughbook, figure out what frequencies they used and work my way from there.

I'm just having a bit of fun and testing how smart (dumb) I am. Ultimately I can find out which one of the several frequencies, that my WWAN module supports, will be favored by our quarter wavelength antennas.

I have the CF-29 lid you sent me Jeff. The overall length is 77mm or 7.7cm. No idea what MK the donor 29 was.

If that antenna will/might work for you Nick, PM your mailing address and I will send it out.

Off to the races, actually, off to watch the race, season opener for F1 in Australia. L8R.

Thanks for the offer, but if I go by what Jeff says, his 73mm doesn't fit in the CF-30, so yours wouldn't fit any better. I'd have to get one of his smaller ones.

From my calculations, 77mm is close to a half wavelength of 2100Mhz (~143mm / 2 = 72mm rounded up ). At quarter length it would match with upper 900Mhz bands used in Europe and Asia.

Disclaimer: I don't know enough on the subject to be 100% sure of anything I'm writing.

Ok, no worries. Thought I would offer what I had as it might have saved time and shipping cost. No idea what MK of 29 or where it came from, before it came from Jeff.

Hey kode,

PM your address please. I can't find it. Ship first class padded envelope tomorrow.

Thanks,

Jeff

Finally received it. I don't know why it took so long, maybe because the envelope had a delightful leather smell and customs had a go at it?

Thanks Jeff.

Again the longer one with the silver is from CF-29 MK4 and earlier.

kode-niner wrote:It's all guesstimating anyway. I can't be too precise since I'm not sure if the little cap on the end adds to the length. It would probably be easier to find which carrier was originally locked to the WWAN in that toughbook, figure out what frequencies they used and work my way from there.

kode-niner wrote:Cool, thanks! Can you measure the longest one in centimeters? I want to calculate the wavelength it was meant for. Also, if you know what WWAN card was in that MK2 or we can figure it out from the model code.

You can not apply formulas that are intended for a dipole or a ground plane to a wound manufactured antenna. As you have stated, you may be dealing with capacitance hat, or a bottom load, the tightness of the helix and even the diameter of the antenna wire all effect the "Q" (Bandwidth) and frequency.

Here a quick test, do your intended formula show the antennas to be the correct length, if so, you might be on to something. Generally speaking, the frequency is what the manufacturer says it is, for it's intended application. Does that mean we have to listen to them, well I never do...

Sadlmkr wrote:Again the longer one with the silver is from CF-29 MK4 and earlier.

As you mentioned, it's too long for the CF-30 without making a few modifications but I'm happy to have it for testing!

Azrial wrote:You can not apply formulas that are intended for a dipole or a ground plane to a wound manufactured antenna. As you have stated, you may be dealing with capacitance hat, or a bottom load, the tightness of the helix and even the diameter of the antenna wire all effect the "Q" (Bandwidth) and frequency.

Here a quick test, do your intended formula show the antennas to be the correct length, if so, you might be on to something. Generally speaking, the frequency is what the manufacturer says it is, for it's intended application. Does that mean we have to listen to them, well I never do...

That's a hard question to answer. What complicates the issue is that all WWAN cards support several bands, either as multi-carrier devices or network fall-backs for the sake of coverage while roaming on partner networks or switching to 2G. Some even use different bands for upload and download, like AWS. So obviously there are compromises that have to be made. Granted, they may choose the "main" band for a particular carrier and optimize the antenna for that. So here's a better question that might be easier to answer: when Panasonic ships a system for use over Verizon, Sprint, AT&T or for Europe, do they ship with different antennas? In other words, do they have carrier or band-specific antennas with different part numbers?

Yeah, calculations are all different for dipole, monopole, inverted-V, etc.... Luckily there are online calculators for that. Toughbook antennas are obviously monopole so relatively easy to figure out. And then there's the issue of half or quarter length. For example, 1200Mhz is 2.34 inches HALF length but 2100Mhz is 2.67 QUARTER length. So the same antenna can roughly be used in both cases.

The 29 and 30 have components at the base of the antenna. There is a thread on NBR about it.