Re: QCX & Ant Tuning


Hi all, please look at this link:

“The QRPGuys LED Tuning Indicator is a standalone SWR 50Ω HF bridge that can be used with your existing tuner if it does not have built in SWR indication. It can also be used without a tuner if you are adjusting your antenna for its best resonance. Simply place it between your rig and tuner or antenna and tune or adjust your antenna for the LED to go out.  The device is rated at 10 watts PEP, 5 watts CW max. and incorporates the N7VE LED absorption bridge circuit for sensing SWR. In the TUNE position, you cannot damage your transmitter caused by a high SWR. From a shorted antenna to an open antenna, your transmitter is looking at a maximum of 2:1 SWR in the TUNE position. At full brilliance your SWR is 4:1 or greater, at half brilliance your SWR is approximately 2:1, and the LED will completely extinguish at 1:1. It has a male BNC input for direct connection to your radio without adapters and a female output connector for coax to your tuner or antenna. In the “Operate” position RF passes straight through and can stay in the circuit.

Additionally, after the antenna is tuned up, keeping the bridge in the circuit (“Tune” position) will reduce the power by a factor of four to a matched antenna. This can occasionally be useful when trying to bring a 3w QRP transmitter to under the 1w level for certain sub-one watt contest multipliers. This kit can be built in an hour or so. On a difficulty scale of 1 to 5, 5 being the most difficult, this is rated at 2.

It is small, compact, lightweight, 1.50″ x 1.25″, and weighs only 23g. (.8oz.)”

Juan Herrera HK6J 
Enviado desde mi iPhone

El 30/07/2018, a la(s) 9:51 p. m., Leland L. Bahr <w5drc@...> escribió:

Reason I asked was, for the most part I operate at the home QTH so I can tune my tuners with a larger rig and then switch over to a small radio such as a QCX.  Consequently there is no high SWR on an unprotected radio.  I never gave a thought to those small indicators which put a slight load on a rig like a QCX while tuning and keep the SWR to around 3:1 or less.  (I'll take your word for it this is true.)  Am I correct then in assuming a 3:1 SWR for short 15 second transmission won't hurt the QCX finals?

One of the comments was tune the tuner first for the greatest noise.  I understand this, but this does not always work.  Many times when doing this and then applying power I find the SWR out of sight.  Experience has taught me not to rely on this method. This might work with some tuners but not with mine.

The suggested Pacific Antenna SWR Indicator intrigues me.  Is anyone on here using one and can confirm it works well with a QCX?  Or at least anyone using a similar device with no final burn out problems?

I appreciated and appreciate all these comments on the topic.

Lee, w0vt

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