I am experimenting with Tayloe switching front end.
I have an FST3253 switching mixer, fed from 74ac74 divider and an SI570, with a FIN1002, controlled by an MC9SQ8QG8 and 24AA32 controller. An LT6231 op amp amplifies the whole thing.
The set works excellent, but I have noticed a 1Khz backround tone, present on alll bands and frequencies, it is static, does not change in t frequency or level.
Any ideas how to eliminte please ! The whole project is well decoupled.
Paul

There is no RF at all audio stages.
 
In the case of the switching mixer (Tayloe), I am injecting some +20db's or 2.40 volts from the 74ac74 into the switching mixer. The I Q  levels are perfectly matched.


In the diode ring mixer, (R2pro)  I will probably have to reduce the LO level to the theoretical +7db's. At present I am pumping +13 db's

I am looking for an am rejection circuit, or some other method, able  eliminate BC broadcast breaktrough  in DC rx's.

 I am experimenting with DC receivers, and despite claims, that DC receivers employing diode ring and Tayloe mixers will stop any broadcast am breaktrough, this is not happening !   I would have tought that the use of a rejector circuit at the antenna will stop this annoying complaint, but I have not seen any on the web. Any suggestions  please ?

Does anyone knows how to measure RF phase shift, without the use of an oscilloscope ?

I am looking to buy a decent external remote ATU, max 100 watts, which can tune anything, longwire, G5RV, dipoles, verticals etc.
Which is the ideal ?  MAC , CG,  MFJ,  SG,  LDG ?

I am looking to buy a decent external remote ATU, max 100 watts, which can tune anything, longwire, G5RV, dipoles, verticals etc.
Which is the ideal ?  MAC , CG,  MFJ,  SG,  LDG ?

Hi all,

I intend to buy an external atu, as I believe that the swr, should be tamed at the antenna external  feed point, not at transceiver point.
Which is the most quoted, the best on the market for all situations - long wire, dipole, G5RV, etc etc. indeed for every situation !!

I used to be a member of GQRP, but I resigned, because I was not being treated like British and US amateurs. The forum is run on very strict  Rule Brittania, rules and highly biased against DX amateurs !
I have ordered some components, three times, and every time, I found missing components in the parcel ! The last time I ordered components, I got no reply !

Hi all.

I am looking for a list of small vendors of components, who operate from home, able give you that personalized service, with decent shipping charges, and no minimum quantities

Thanks for your comments.
We may also have to beef up the swr sensing circuit !
I have a motorized wide spaced 500pf variable capacitor, and taught of making use of it, replacing the smd capacitors. But maybe that would require software mods. And the source code for the original T1 is not even available anywhere.

Hi all,
I am looking for a pic program to control an antenna tuning unit, similar to the Elecraft T1, but for outdoor use and capable of 100 watts !

Anyone knows of any mods to the Elecraft T1 auto atu modified for 100 watts !

Don,
Thanks for your reply.
I need to use the transformer to match the antenna input LPF to the input of a Tayloe type switching mixer. Now, I understand that the transformer should be connected with the 50 ohms to match the LPF, and the 200 ohms should go to the mixer switches. However, I have seen circuits doing the opposite ( mistake ?)

I need to connect the Minicircuits TT4-1A RF   1:4 ratio transformer.
The data sheet does not specify if the primary is 1  or 4  (50:200 ohms)??
Also I need to connect it to a switching mixer. I am assuming the 200 ohms (4) should go to the mixer input !