Re: Issue with high SWR on transmit

Bryan Brauer


I am having almost exactly the same experience; with the 20 meter D4D as well as with the QRPGuys DSB TRXCVR.  I am inclined to believe that double side band is not a good way to go.  I suspect that the signal is just to "dirty" to decode dependably.

I will try a bit more, this time with a resonant dipole. I thought that this radio might be a bit of fun, and I enjoy building kits, but life is to short to muck around with such marginally functioning equipment.  If the dipole does not produce dramatically different results, I will go back to my KX2 for FT8.


Bryan, AI6B

On Sun, Nov 17, 2019 at 8:22 PM Kurt Loken <kurt.loken@...> wrote:

Hello All,

I have a 20M D4D, and I think I may have a problem with it.  

I have been a bit mystified that I have so far only had 1 contact on this thing even though I've been on the air with in for many hours.  I had been thinking it is due to my use of an indoor experimental magloop antenna and the 1W is just isn't making it out of the house.  Yet...what has bothered me is that I have a WSPRlite that only puts out 0.2W and I get picked up all over the is a picture of my spots I got on 20M today with my setup with 0.2 watts on my antenna.  
Screen Shot 2019-11-17 at 10.00.08 PM.png

I have good FT8 reception on the the receiver part of the system is working like a champ.

I am just getting back into working on radios after a long hiatus and I have have an antenna analyzer, but I actually didn't have a normal SWR meter so that could read my transmissions insitu.  Today I got one.  ...and low and behold...I have horrible SWR readings during transmit when I run the D4D.    I have an Elecraft W1 Power Meter and the SWR pegs out when I transmit.  If I transmit into a dummy load, I get perfect SWR and perfect 1W output. 

I am using a mag loop antenna that is tuned to the 14075 (see pic).  The bandwidth shown is around unless this thing is way off on the transmit freq or noisy as hell, I should not be seeing huge SWR.


Any ideas what is going on?  I would be curious what the spectrum my D4D looks like in transmit, but I don't have that test equipment yet.  I'm getting a Red Pitaya very I will be able to to measure that in the future.  

I don't understand what is going on with the high SWR...any ideas?  



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