Maestro freezes on 17m

John Gilbert

Using a Maestro A on battery and WiFi with a 6500 s/w rev. 2.4.9. Attempting to tune or transmit on 17m meters freezes display, and subsequently, slice disappears leaving two blank slice headers. This happens on 80m, too. 20m operation is OK. Again, Maestro is on battery in compartment, freshly charged. No other connection, other than microphone. SSDR works fine. Any ideas?

Mack

What are the results if you test into a dummy load? This sounds like an RFI issue. Or what happens if you turn the power level down to one watt? Mack W4AX Alpha Team

John Gilbert

Dummy load tests fine, as does 1 watt. So looks like RFI is entering without connections, other than mic which has a double wound choke at input.

Mack

John,

Yes, it's RFI. May I suggest this product in line with your coax to most likely eliminate the common mode RFI on your coax? https://www.balundesigns.com/model-1171-1-1-atu-current-balun-1-54-mhz-5kw/ Note: I have no commercial interest in this product. Balun Designs simply makes the best chokes on the market. 

73,

Mack
W4AX
Alpha Team

John Gilbert

Antenna is a Random Wire End Fed built with a Balun Designs 9135 Unun and choked just inside the radio room window with a Balun Designs 1116di isolator (choke). There is 3 ft of coax from the window entry to the isolator, and 5 ft of additional coiled and choked (4 turn, mix 31) to the radio. I could put the isolator outside the window, but doubt that is the issue.  Probably the problem is the RWEF is wrapped around my condo on 6" standoffs, 20 ft up on a hill of another 20 ft. So, the Maestro at my desk is 10 ft from the antenna on the outside wall.  

Further experimentation shows that I can QRP (5w) on 17m via the Maestro, but not tune, even at 1w. The tuning circuit must be spiking when it starts.

20, 40, 80 (now), and 160 are working on tune and transmit at 40w. 17m and 15m lock up on tune and transmit. 

Short of wrapping the Maestro in tin foil, not sure what else to do. I'm limited in space. I can't get away from the antenna any reasonable distance. 20 to 160 meters is good enough value, and I guess I'll live with QRP on 17m.

Thanks for the help.

John Gilbert

I think 80m might have been fixed by a 10 wrap double ring mix 31 choke on the ethernet cable, which I've re-attached, and 10 wrap single ring mix 31 choke on the power connection which I'm now using instead of battery. I think I'm going to use a fiber optic run from the switch the 6500 is on, up a floor to my desk. That will eliminate one variable. I'll still be too close to the antenna for the upper bands.

Tim VE6SH

When I switched to fiber from ethernet cable the vast majority of my RFI problems went away. 

Tim VE6SH

K0FLY

John:

You maybe getting RF into/onto the Cat5/6 Ethernet cables as well as the 12 volt power to the Maestro.

DX Engineering has some Ethernet filters that you can insert between the radio and cable and the Maestro and cable, the are pricey,or you can get some mix 31 clamp on cores for RG-8 cable , wrap multiple turns of the Cat5 or cat 6 cable through it. Place one at the Maestro and one at the radio.  Also use one of the cores on the + 12 volt power line to the Maestro.   DX engineering, Pro Audio, and Mouser have the cores in stock. I'm not associated with any of the above stores.  You use multiple turns through the cores because the choking impedance multiplies by the square of the turns.

Google W1HIS or K9YC for RFI choking information, down load the articles.  

I haven't had any problems at the 100 watt level but at a  KW i have, even the HDMI cables had to be choked.

Gayle K0FLY

John Gilbert

Gayle, Thanks for the reply, but as stated above, the issue exists on battery power with no connections excepted a choked microphone. Also note, that when using ethernet and direct power, those lines are choked to the hilt (Palomar ferrites). This, I believe, has brought back 80m. I will look for further opportunities for strangulation.

K0FLY

Sorry I didn't understand the battery , I forgot about the internal battery option even though you stated so.    Sounds like you go things choked. 

Gayle

Bill W2PKY

May try altering the length of the antenna and or transmission line to reduce the SWR on 17M. 

John Gilbert

Bill- Thanks for the suggestion. The end-fed is optimized now for all bands with an acceptable level of compromise on each band.

Here are the numbers: 2.0 (160m), 1.8 (80m), 2.8 (40m), 2.2 (20m), 2.7 (17m), 1.5 (15m), 2.6 (12m), and 3.3 (10m). I'm hovering around 2.0 on 160, 80, and 20 meters. When I change the length either way, 40m gets worse, so to keep it in the ballpark, I settled on the length it is, which I think is in the neighborhood of 56 ft in a flat L wrapped around the building, 6 inches off the wall. About 40 ft of that is a straight run.

That said, I may need try some experiments with feed line length, as it is an integral part of the end-fed antenna system, and directly related to SWR. Thanks for reminding me. Improvements may be possible.

Also, I've toyed with the idea of a separate specific 17m dipole, if I can figure out how fit it in the space that I have. I'll think some more on that, too.