Earlier in the year I wired up a Comet GP15 antenna in my attic. Yesterday I finally had a chance to test it!

It’s nice being able to peer inside what seems like such a closed system: an antenna and a feedline.

In my tests I had around 60 feet of feedline between me and the antenna, but in the few spot tests I’ve done the feedline doesn’t seem to affect things very much. I’m using very low loss LMR-400 coax to hook things up and it’s some top-shelf stuff.

The box itself is around 4x7x2.5 inches around (not counting the antenna socket and the knobs) It has a very simple interface — you dial in the frequency and it tells you about what it sees.

It give you a lot more than just the standing wave ratio (SWR) of the system, it breaks it down by te resistive load versus the reactive load. It doesn’t go so far as to tell you if it’s a capacitive or a inductive load, but you can figure that out by sweeping the frequency around a bit. It doesn’t have the capabilities of a $20K network analyzer, but it’s a good product for what you’re paying for it.

Overall I found that the antenna is quite good in 2m and 70cm, but it’s just not all that on 6m.

 

6 Meter
Frequency SWR Rs Xs
50.0 4.0 56 69
50.2 3.6 39 54
50.4 3.4 28 42
50.6 3.2 22 32
50.8 2.9 20 23
51.0 2.5 19 16
51.2 2.2 21 7
51.4 1.9 25 0
51.6 1.5 31 4
51.8 1.2 41 8
52.0 1.0 50 3
52.2 1.1 53 5
52.4 1.3 49 12
52.6 1.4 41 15
52.8 1.6 35 14
53.0 1.7 30 12
53.2 1.9 26 7
53.4 2.1 23 1
53.6 2.2 22 3
53.8 2.4 20 5
54.0 2.7 20 9

 

 

2 Meter
Frequency SWR Rs Xs
144.0 1.6 46 24
144.2 1.6 42 21
144.4 1.5 39 17
144.6 1.5 37 13
144.8 1.4 37 10
145.0 1.3 38 7
145.2 1.2 39 4
145.4 1.2 41 3
145.6 1.1 45 3
145.8 1.0 48 3
146.0 1.0 51 3
146.2 1.1 52 5
146.4 1.1 52 8
146.6 1.2 51 11
146.8 1.2 48 14
147.0 1.4 44 16
147.2 1.5 40 16
147.4 1.5 37 15
147.6 1.6 34 13
147.8 1.6 32 11
148.0 1.7 30 7

 

 

 

440 Mhz
Frequency SWR
420 1.9
420.5 1.7
421 1.5
421.5 1.3
422 1.1
422.5 1.3
423 1.5
423.5 1.9
424 2.1
424.5 2.2
425 2.1
425.5 2
426 1.7
426.5 1.4
427 1.2
427.5 1.3
428 1.6
428.5 1.9
429 2.0
429.5 2.2
430 2.1
430.5 2.0
431 1.7
431.5 1.4
432 1.2
432.5 1.2
433 1.4
433.5 1.7
434 1.8
434.5 1.9
435 1.9
435.5 1.8
436 1.6
436.5 1.4
437 1.2
437.5 1.1
438 1.2
438.5 1.4
439 1.5
439.5 1.6
440 1.5
440.5 1.5
441 1.4
441.5 1.3
442 1.4
442.5 1.4
443 1.5
443.5 1.5
444 1.4
444.5 1.3
445 1.1
445.5 1.1
446 1.3
446.5 1.5
447 1.7
447.5 1.8
448 1.7
448.5 1.8
449 1.7
449.5 1.5
450 1.2