|Amazing accuracy on SWR
||Time Owned: more than 12 months.
|Presently own 2 TW-1 's and 1 TW-2, they are great . Very accurate SWR which is calculated from the Forward and Reverse power measurements using the Reflection Coefficient formula. Proven accuracy less than 3% error in the calculated SWTR . For the actual readings For=95W, Rev=3.6W unit yields SWR=1.5 . Using the reflection coefficient formula for SWR and the for and reflected power measurements SWR=1.47 is calculated proving that the 1.5 SWR is less than 3% away. The tone mode is the most fantanstic addition, suighted or unsighted it allows for heasds up tuning of antenna or power amp; when the SEWR tone reaches min the SWR is min; when the For power tone reaches max the power out of an amp is max. Excellent for mobile operation as the unit is 12vdc powered and allows attention to the road while tuning manual tuners, or in the dark tune ups. |
Earlier 4-star review posted by W2OZ on 2009-02-08
I am a blind ham for the last ten years and I love my two LDG TW-1's and my TW-2 , they keep me safely on the air, mobile and fixed. I can tune up faster than many of my sighted friends to their amazement. However all is not perfect, the TW-1appears to have an error in the calculation of the SWR, as it reports an SWR much worse than what is calculated by it's own Forward and Reverse power readings. If you only listen to the SWR you will never notice that while you think you are at .5 :1 you are really at 1.05 and splitting hairs to get better ! Sitting across the shack is one of the units reading Forward=95W, Reverse=3.6W but says SWR=1.5 , something is amiss ! using the formula for SWR=[For+Rev] / [For-Rev] and the TW-1's measurements for Forward and Reverse power you get SWR=1.07 : 1 , much better than the reported 1.5 to 1. While this error is in a direction that does not harm equipment as the tendency is to keep tuning for perfect, it is a bad inaccuracy and is disappointing since the main instrument is very easy to use and simplifies the tuning procedure . I have recomended this instrument to sighted hams who want to tune up while mobile without looking away, because of the tone tune up via SWR , the lowest pitch is 1:1 . 1
|very accessible, very accurate and easy to use
||Time Owned: 0 to 3 months.
|This meter is the perfect instrument for the blind/visually impaired amateur, or those who need to be looking else where while checking forward or reflected power, or antenna SWR. The box has no visual meter on it, and mearly speaks either in verbose, or short terms the values you are looking for. A volume Pot on the front allows for quick adjustment of the voice loudness, and the 3 easily located buttons on the front make it easy to use. I have no need for the German or Spanish language features, but these are surely useful to those who would use them. I am totally blind, and have been needing a watt/swr meter like this for a long time and now I have one, and am able to independantly check power and SWR. Previously, there was a meter produced that gave power/swr readings in CW, but since I do not use or understand CW, this meter was fairly unaccessible.|
The tone modes, one for swr tuning, and one for power tuning, make it exceedingly simple to use an external tuner by listening to the pitch of the constant tone, and the tuning of a liniar is made that much easier by listening to the very accurate pitch of the tone used for power.
I give this unit a 5 because of its need in the ham world, and because it is an accurate well designed peace of equipment that keeps simplicity and cost in perspective. Most peaces of equipment that have built in voicing capabilities are very expensive. LDG though has made sure that this watt/swr is, generally speaking, well within the price range of an amateur who needs or wants it.
The only things i would change about the design of this meter are its chassy and the power requirements. The chassy is a little bit flimsey on the rear where the SO239 connecters are located, and the panel does move quite a bit when connecting heavy duty coax. Also, i would have liked the ability to install a 9VDC battery into the unit for field use, instead of having to use an adapter plug for power requirements. These however are rather miner issues. The chassy can probably be easily strengthened with a few well placed machine screws and nuts, and the need for an external power source is likely a necesity because a battery compartment would make the unit larger in size.
Excellent unit for the price, level of accessibility and the simplicity of operation.