Problem solved A crude homemade notch filter was all my Kenwood R599 receiver needed. For my transceiver I bought a Morgan Manufacturing model M-402X BCB filter. You can transmit through this filter without any TX/RX switching. Works great.

Bobby Dipole ND9B

I've always used "Coax-Seal" outdoors on my PL259/SO239 connectors, and never had any moisture incursion. But, that stuff is a bear to get off when you need to disconnect. And, if it's cold outside, forget it!

Has anyone tried using this new Silicone Tape (also known as Rescue Tape)? I'm sure it would be easier to remove, but does it keep the moisture out?

Bobby Dipole ND9B

The SWR on my HF antenna recently went to hell in a hand basket. It turned out to be a corroded SO239 barrel connector splicing two lengths of coax together outside. After replacing the connector, I noticed the local AM broadcast station (that I'm very close to) went from +60 over 9 to +80 over 9. (Now I need a BCB filter, but that's a different topic.) After making some contacts, I believe reception in general is stronger.

Now the corrosion on the barrel connector probably didn't happen over night. Is it possible that it was affecting RX but not TX for a period of several years? And, then finally got bad enough to affect TX?

Bobby Dipole ND9B

I live close to an AM station on 1350 KHz. My Kenwood TS-570 can handle it WITH the attenuator turned on, but my old Kenwood R-599 is severely overloaded even with the RF gain turned down.  I think a notch filter tuned to 1350 KHz would be just what I need. Are there any commercially available units that would fit the bill?

Bobby Dipole ND9B

I just lost the bid on a M-Cube LCRZ meter on Ebay. Unfortunately these are no longer in production, and used ones are as scarce as hen's teeth. Is there anything like it on the market in the "hobby" price range?

Bobby Dipole ND9B

The manual only says "adust so that the ALC meter reflects according to your voice level". Where should my voice peaks register? Low, middle, high on the scale?

Bob ND9B

The MFJ-998 is in a chain: Rig-Amp-SWR meter-MFJ-998-Antenna. The linear amplifier is an old Heathkit SB-1000. I just discovered that with a dummy load directly on the output of the amp (with the amp in Standby or Off), the SWR measures 1.5:1 on 20M on the rigs meter. Evidently, the amp is not providing a good 50 ohm feedthrough. (The SWR gets better at lower frequencies.) So maybe the problem is that the input to the tuner is not a good 50 ohm source, at least not on 20M. Does this sound plausible?

BTW, the antenna relay in the Heathkit amp looks like it came out of a washing machine. It definitely wasn't designed for RF!

Bobby Dipole ND9B

I have a MFJ-998 antenna tuner that's not doing a very good job of automatic tuning on the 20M band. At my favorite 20M frequency the tuner will tune and read out 1:1, but my external SWR meter (which I trust) reads 2:1. I can go to manual mode and get the SWR down to 1:1. I can then press [TUNE], [C-DN] and [L-DN] to store this setting in memory. BUT, how do you recall the stored setting? I can find no way restore the setting in memory, the tuner always initiates a new tune cycle and lands up back at 2:1 ! What is the point of the memory banks, if the tuner is going to retune anyway?

Bobby Dipole ND9B

I'm looking for a new soldering iron for general printed circuit board use. Two things it must have: It's own power switch and a pilot light. I do a lot of home brewing, so my iron is on for long periods of time. Any recommendations?

Bobby Dipole ND9B

I have a Yaesu FT-857D in my car. On trips I often slide down to the AM broadcast band. Here's the weird thing: I swear all the program hosts that I am familiar with, sound like different people. All the voices are slightly high in pitch. How can this be? This is AM not SSB! Is this some sort of DSP voodoo? Can this be fixed? It's driving me nuts.

Bobby Dipole ND9B

I need to move the resonance point on this antenna on 80M and 160M. I know you change the length of the sections between the two coils to tune 80M, and you change the length of the end sections to tune 160M. But, by how much? Is there a rule of thumb for kHz per inch? The instructions from Alpha Delta just says change it a few inches at a time. It's rather tedious to lower and raise my antenna, so I want to minimize the number of adjustments.

BTW, are the coils on this antenna doing double duty as both loading coils and traps? Quite a trick.

Bobby Dipole ND9B

I just realized that I could measure the switche's isolation with my RF generator and the S-meter on my rig. I cranked the generator up on 20M (the highest freq band I use) for a reading of 60 over 9, then flipped the coax switch. The S-meter fell all the way to the end of it's range. The isolation must be at least 100db if the meter is right! I see no problem now.

Bobby Dipole ND9B

I have two high powered rigs that I want to use with one antenna. Would it be safe to use a Daiwa CO-201 coax switch for this purpose? This particular switch shorts the unselected port to ground, but the actual isolation is not specified. I just want to make sure transmitting on one rig won't nuke the other.

Bobby Dipole

Can anyone recommend a circuit analysis program for the PC that will run under XP? I have used Spice, but that was 35 years ago on a main frame. This is for hobby use, but I don't want something that is too stripped down. I don't anticipate modeling any circuits with more than 4 opamps or transistors. I need something that can sweep frequency and output a Bode diagram.

ND9B

I need to make some 1/2" holes in an aluminum chassis. I want to make these holes nice and "clean". At work, we would use a giant "Whitney" punch or "Greenlee" knock-outs. But, I don't have access to these tools at home. My experience with regular bits and sheet metal is UGLY holes.

This may sound crazy, but is it possible to use wood "Spade" bits on soft aluminum sheet metal? I have a set of wood spade bits that have "ears" on the ends. They make absolutely perfect holes in wood, thick or thin. Could these bits handle thin aluminum, if used in a drill press at low speed? (I figure it's steel vs aluminum, the steel ought to win.)

ND9B