Using ship's antenna for handheld?

[EricJ]

58 minutes ago, Marauder said:

Nope. It went into the electronics graveyard with the rest of the misfit and dead toys. I do know that were using some sort of signal strength gizmo to look for loss along the antenna path. They tracked it down to the splitter and it was removed.

The signal loss was also noticeable with the splitter removed but to a lesser extent. I ran all new RG-400 and let the shop makeup the new BNC connectors. This was the stuff I was finding when I pulled the RG-58.

 

Thanks, I may have my KX99 to take apart in a month or so depending on what shakes out.

Kinks and crimps, or even just sharp-ish bends, can be bad in coax.   Otherwise age related issues are usually more around corrosion or dirt in connectors.   Holes or frays in the shield don't help anything either.   RG-400 is good stuff, so that kind of abrasion on the old stuff is as good a reason as any to replace it.

Edited March 17, 2018 by EricJ

[Jerry 5TJ]

On 3/16/2018 at 2:24 PM, Yetti said:

I think these are aircraft approved

https://www.radiotwoway.com/rdd5227a-152-162-mhz-1-4-wave-stainless-antenna?utm_source=google&utm_medium=cpc&adpos=1o5&scid=scplp15709&sc_intid=15709&gclid=Cj0KCQjw1q3VBRCFARIsAPHJXrF3n8gTLGhel8OvYDYKwHrpjjACeV3LXZJ8KZwQpWUt9paYz0_ZNhoaAu1nEALw_wcB

Wrong frequency band:  You need 118-136 MHz. 

I used one like this

http://m.aircraftspruce.com/catalog/avpages/av-17.php?clickkey=9801

 

[ShuRugal]

Wrong frequency band:  You need 118-136 MHz. 
I used one like this
http://m.aircraftspruce.com/catalog/avpages/av-17.php?clickkey=9801
 

$120 for a god-damned dipole whip? You can literally make one out of a coat hanger that has identical electrical properties. Where do these people get off??

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[Jerry 5TJ]

35 minutes ago, ShuRugal said:

$120 for a god-damned dipole whip? You can literally make one out of a coat hanger that has identical electrical properties. Where do these people get off??
 

A wire coat hanger will work better than a plastic one.  Cut it to about 23” in length.  

[Yetti]

I was under the impression that ~12" was VHF quarterwave

[Jerry 5TJ]

5 minutes ago, Yetti said:

I was under the impression that ~12" was VHF quarterwave

Only at latitudes where the speed of light is much reduced. 

[Jerry 5TJ]

Here’s a CB who has crafted a nice wire antenna on the bottom of his plane. Note he’s increased the thickness-length ratio, no doubt for  improved bandwidth.  

[ArtVandelay]

Here’s a CB who has crafted a nice wire antenna on the bottom of his plane. Note he’s increased the thickness-length ratio, no doubt for  improved bandwidth.  

That looks aerodynamic

[EricJ]

1 hour ago, Jerry 5TJ said:

Here’s a CB who has crafted a nice wire antenna on the bottom of his plane. Note he’s increased the thickness-length ratio, no doubt for  improved bandwidth.  

Needs more duct tape.

[yvesg]

3 hours ago, Yetti said:

I was under the impression that ~12" was VHF quarterwave

If you go with the real definition of what VHF is, the length of a quarter wave can be anything from 1/4 of a meter to 2.5 meters approx. depending of the exact frequency. This is from 8 to 80 inches in US measurement.

Yves

[EricJ]

15 minutes ago, yvesg said:

If you go with the real definition of what VHF is, the length of a quarter wave can be anything from 1/4 of a meter to 2.5 meters approx. depending of the exact frequency. This is from 8 to 80 inches in US measurement.

Yves

This is why many VHF antennas, like TV rabbit ears, are telescoping/collapsible so that the length can be optimized, if needed, for a particular channel. 

[EricJ]

On 3/15/2018 at 7:43 PM, Marauder said:

 

If you ever lose receive & transmit capability for the radio that the KX-99 is attached to, it is that box that is the problem. Mine failed that way. The resistance was extremely high on failure.




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Dropped my airplane off for some avionics work today and I asked about the KX99.   They confirmed that it is a switch and not a transformer/splitter, and therefore fairly desirable compared to a splitter (lossy) or diplexer (expensive).   When yours failed it may have been the switch not completely making contact, which would have resulted in an open circuit and therefore high resistance.

I'm going to keep mine for the time being.  If it ever fails then repair can be attempted or just replace it with a bulkhead fitting and connect the handheld to the antenna cable directly.