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L-Per Antenna

Started by kdvthree, February 04, 2019, 11:00:08 PM

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kdvthree

I have need for a replacement antenna for my L-Per on 121.5mhz.     The unit is the blue colored receiver and is about 30 years old.  Works great.

Any one have one available

Ken V

SarDragon

You can try e-bay, but I haven't seen any useful L-per gear on there in several years. Are you missing the antenna completely, or is yours just in need of repair?
Dave Bowles
Maj, CAP
AT1, USN Retired
50 Year Member
Mitchell Award (unnumbered)
C/WO, CAP, Ret

PHall

Quote from: SarDragon on February 05, 2019, 12:13:59 AM
You can try e-bay, but I haven't seen any useful L-per gear on there in several years. Are you missing the antenna completely, or is yours just in need of repair?

I'm willing to bet it won't DF anymore but will receive. Those lovely diodes!

SarDragon

OP, PM me with your email address, and I'll send you the antenna schematic and parts info.

The diodes and resistors inside the little blue box are VERY small. They require delicate and precise soldering, and diode polarity is important. The lengths of the cables are critical, so you need to be careful during disassembly, so you maintain the correct lengths.

If you have the antenna version with the molded cable connection, you're pretty much screwed.
Dave Bowles
Maj, CAP
AT1, USN Retired
50 Year Member
Mitchell Award (unnumbered)
C/WO, CAP, Ret

c172drv

Tap into your local HAM radio club. They will likely have a few folks comfortable with making new replacements for old equipment.
John Jester
VAWG


JayCraswell

How about a FLEX YAGI?
I designed (liberated the idea and scaled the antenna) a flex Yagi antenna that connects to the LPERs.  It only works in RECV mode where you move the antenna in a few 360s and look for the peak.  Which is good because I loath DF mode.  You get the same indication if your walking directly at the target or walking directly away from the target.  Plus its not good for close in and doesn't handle reflections well. I know I know its "easy" but no one has ever won our Wing Foxhunt (UDF) doing it in DF mode.

Or better yet turn the sensitivity way down and listen for the signal when every direction is noise except one.  I believe our german transplant CAP member told me that the dynamic range of human hearing is far better then your eyeballs squinting at the signal strength meter. I can report that doing it by sound seems to always put me on the correct cut (azmuth) when in an area with lots of reflections (hangers / other aircraft) 

It still fails if your dumb enough (Like me at a mission years ago) to stand under a power line where you just end up walking directly under the wire. 

Step 1 get out in the clear and get up as high as possible. Or ask for an Aircrew that knows how to do an electronic search.

1) Advantages are greater range. 

2) Sharper "cuts"

3) Its able to be bent in 20 different places. Like when your crashing through brush or the woods. It comes back into shape just give it a firm shake and it folds back into place.   You can also fold the elements and use velcro to hold them down so you can load it into a van without it taking up a bunch of space.

If you want an assembled and tested one I make them up in batches on a fairly regular basis.

Its made from PVC and chopped up lengths of metal measuring tape which is spring steel.  Painted green its what the whips on Army Packset radios such as the PRC-8, 9, 10, 77 etc all use.

I'm normally reachable at (505)  333-9301 and its ok to call late (say 11 PM CST)